HTP MTS 160 User manual

MTS 160
Owner’s Manual
HTP America, Inc. •3200 Nordic Road •Arlington Heights, IL 60005-4729
1-800-USA-WELD •847-357-0700 •FAX: [phone] •www.usaweld.com

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Manufacturer’s Warranty
It is expressly agreed that there are no warranties, expressed or implied, made by either the Salesman, Dealer, or HTP
America, Inc. on products or parts furnished hereunder, except the Manufacturer’s Warranty against defective materials or
workmanship as follows:
HTP America, Inc. warrants each new MTS 160 welding machine to be free from defects in material and workmanship
under normal use and service for two years after delivery to the original purchaser. HTP America, Inc. will repair and
replace, at its factory, any part or parts thereof, products to be returned to HTP America, Inc. with transportation charges
prepaid and which its examination shall disclose to its satisfaction to have been thus defective. This warranty being
expressly in lieu of all other warranties, expressed or implied, and all other obligation or liabilities on its part and it neither
assumes nor authorizes any other person to assume for it any other liability in connection with the sale of its machines.
This warranty shall not apply to any welding machine which has been repaired or altered by unauthorized service
departments in any way so as in the judgement of HTP America, Inc. to affect its stability and reliability, nor which has
been subjected to misuse, negligence or accident.
HTP America, Inc. shall not be liable in any event, unless HTP America, Inc. receives notice of alleged breach of warranty
within 30 days after the discovery, actual or construction alleged breach of warranty specifying the claimed defect.
HTP America, Inc. has reserved the right to make changes in design or add any improvements to its products at any time
without incurring any obligation to install same on equipment.
This warranty is void unless warranty card is sent to HTP America, Inc. within 15 days from the date of purchase.
NOTE: Exclusions To Warranty:
1. The welding gun is warranted for a period of ninety (90) days against defects in material and workmanship.
2. The swan neck, nozzle spring, contact tips, gas nozzles, and liners are consumable items, WHICH CARRY
NO WARRANTY.
INDEX
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Safety Suggestions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Electrical Connection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
Front Panel Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Front Panel Receptacles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Polarity Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Feeding the welding wire . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Shield Gas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Mig Welding with your MTS 160 . . . . . . . . . . . . . . . . . . . . . . . . 8
Seam Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Stitch Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Spot Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Hole Filling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Welding Aluminum . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
Stud Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Welding Muffler Pipe. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Broken Stud Removal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Welding Cast Iron . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Tig Welding with your MTS 160 . . . . . . . . . . . . . . . . . . . . . . . . . 14
Tungsten Electrodes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
General Welding Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Filler Rod for TIG Welding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Arc welding with your MTS 160 . . . . . . . . . . . . . . . . . . . . . . . . . 16
Maintenance and Service. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Changing the Contact Tip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Changing the Gas Nozzle. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
Setting the Pressure on the Pressure Roller . . . . . . . . . . . . . . . . . 18
Changing the Drive Roll . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Testing and Changing the Liner. . . . . . . . . . . . . . . . . . . . . . . . . . 19
Monthly Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
MIG Welding Wire. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Wiring Diagram – MTS 160. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Parts Breakdowns – MTS 160 . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Trouble Shooting Guide – MTS 160 . . . . . . . . . . . . . . . . . . . . . . 24
Parts Breakdown – 15 Series Welding Gun . . . . . . . . . . . . . . . . . 26
Parts Breakdown – 17 Series Tig Welding Torch . . . . . . . . . . . . . 27
Volt Amp Curve – MTS 160 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Amperage Charts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28

For more information, refer to the following standards and
comply as applicable.
1. ANSI Standard Z49.1 SAFETY IN WELDING AND
CUTTING, obtainable from the American Welding Society,
2051 NW 7th St., Miami, FL 33125
2. ANSI Standard Q87.1 SAFE PRACTICE FOR
OCCUPATION AND EDUCATIONAL EYE AND FACE
PROTECTIONS, obtainable from American National
Standards Institute, 1430 Broadway, New York, NY 10018.
3. American Welding Society Standard A6.0 WELDING AND
CUTTING CONTAINERS WHICH HAVE HELD
COMBUSTIBLES, obtainable same as item 1.
4. NFPA Standard 51. OXYGEN-FUEL GAS SYSTEMS FOR
WELDING AND CUTTING, obtainable from the National
Fire Protection Assoc., 470 Atlantic Avenue, Boston, MA
02210.
5. NFPA Standard 51B. CUTTING AND WELDING
PROCESSES, obtainable same as item 4.
6.
CGA Pamphlet P-1. SAFE HANDLING OF COMPRESSED
GASES IN CYLINDERS, obtainable from the Compressed
Gas Association, 500 Fifth Avenue, New York, NY 10036 .
7. OSHA Standard 29 CFR, Part 1910 subpart Q, WELDING
CUTTING AND BRAZING.
Electrical Connection
Your HTP MTS 160 will only operate when PROPERLY
connected to a 220 volt, single phase power source wired for a
minimum of 25 amps. All electrical connections should be
done by a qualified electrician in accordance with the National
Electrical code and local codes and ordinances. Due to the
large number of 220-volt receptacles, the MTS 160 is supplied
without a plug. When installing the plug, the green or yellow-
green wire MUST BE CONNECTED TO GROUND, OR
SERIOUS INJURY MAY RESULT. The blue and brown wires
are the hot leads.
Introduction
We congratulate you on the purchase of your new HTP MTS
160 MIG, TIG, and Stick Welder. Your HTP welding machine
will allow you to weld items you wouldn’t have thought
possible to weld. With proper care and maintenance, your new
HTP MIG Welder will deliver years of trouble-free service.
However, it is very important that you read the following
manual completely.
Safety Suggestions
ELECTRIC ARC WELDING PRODUCES ULTRA-VIOLET
RAYS WHICH ARE HARMFUL TO SKIN AND EYES.
ULTRA-VIOLET RADIATION CAN PENETRATE
LIGHTWEIGHT CLOTHING, REFLECT FROM LIGHT-
COLORED SURFACES AND BURN THE SKIN AND EYES.
WEAR FLAMEPROOF WELDING GLOVES WHICH ARE
NOT OILY OR GREASY. THE OIL OR GREASE ON THE
GLOVES MAY IGNITE.
• Wear a heavy, pocketless, long sleeve shirt, cuffless trousers,
and high-topped work shoes. Wear a full-face welding helmet
with a number eight or darker lens and a cap. These
precautions will protect eyes, hair, face, and skin from arc
rays and hot material.
• To avoid fire, do not weld on wood, plastic tile, or carpeted
floors. Concrete or masonry floors are safest.
• Do not weld on drums, barrels, tanks or other containers until
they have been cleaned as described in AWS Standard A6.01.
• Provide adequate ventilation in the welding area at all times.
Do not weld on galvanized zinc, cadmium or lead beryllium
materials unless you are POSITIVE that sufficient ventilation
is provided. These materials produce toxic fumes.
• Do not weld in areas close to degreasing or spraying
operations. Chlorinated hydrocarbon vapors may react with
the ultra-violet rays and form highly toxic phosgene gas.
• If you develop momentary eye, nose or throat irritation
during welding, stop welding immediately. This is an
indication that ventilation is not adequate. Do not continue to
weld until ventilation is improved.
• Exposed, electrically hot conductors or other bare metal in the
welding circuit, or ungrounded electrically hot equipment can
fatally shock a person whose body becomes a conductor.
Do not stand, sit, lie, lean on or touch a wet surface when
welding.
• Frequently inspect cables for wear, cracks, and damage.
Replace those with excessively worn insulation to avoid a
possible lethal shock from bared cable.
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1) Power Indicator Lamp
This lamp is illuminated when the On-Off switch (#7) on the
front of your MTS 160 is turned to the on position and the
machine is connected properly to a 220-volt power supply.
2) Welding Current Indicator Lamp
When the trigger switch on either the TIG torch or the MIG gun
is depressed, welding current will be applied to the welding
torch and the Welding Current Indicator Lamp will be
illuminated.
If your MTS 160 is in the stick-welding mode, the welding
current indicator lamp will be illuminated all the time.
3) Thermoswitch Indicator Lamp
The thermoswitch indicator lamp will light up when the duty
cycle of your MTS 160 has been exceeded. When this lamp is
illuminated, the machine will no longer weld because the
machine has overheated. Leave the machine plugged in and
turned on so the cooling fans can cool the unit down. Allow the
machine to cool for 15 to 30 minutes, the thermoswitch should
reset automatically and your MTS 160 will be ready to weld.
4) Wire Feed Incher
The wire feed incher allows you to feed welding wire into the
welding gun with out wasting shield gas. Depressing the wire
feed incher will start the drive motor, feeding the welding wire.
Note the welding wire will only feed with the side panel closed.
5) Post Gas Flow
The post gas flow is adjustable from 1 sec to 4 sec. Post gas
flow is necessary during TIG welding, because after the arc is
extinguished if the gas stopped flowing immediately, there is
a possibility the molten weld puddle would come in contact
with the atmosphere, causing weld defects. Additionally it
prevents the tungsten from becoming contaminated by the
atmosphere. The gas flow should run long enough to allow
the orange color of the tungsten to disappear. It is important
to remember not to remove the TIG torch from the weld until
the post gas cycle has been completed. If you are welding at
higher amperages or on more critical alloys it may be
necessary to increase the post gas flow to a higher value.
6) Burn Back Time
When MIG welding, as soon as you release the trigger on the
welding gun, the wire feed motor stops turning immediately.
The Burnback Time is the amount of time your welder is still
applying welding current to the welding wire after the wire
feed motor has stopped feeding the welding wire. If the
current stopped at the same time the motor stopped turning,
there is a chance the welding wire would “freeze” in the
molten welding puddle as it solidified. If there is too much
Burnback Time, the wire will melt to the contact tip.
4
Front Panel Controls
123 4 5 6 7
89 10 11
Figure 1

5
Using a screwdriver to turn the Burnback Time adjustment
counter clockwise shortens the amount of time welding current
is applied to the wire, LENGTHENING the amount of wire
sticking out past the contact tip. Turning the burnback time
adjustment clockwise increases the amount of time welding
current is applied to the wire, SHORTENING the amount of
wire sticking out past the contact tip.
Higher amperages and aluminum wire require a shorter
burnback time. To set the burnback time, a good starting point
is to rotate the burnback time knob approximately 25% in the
clockwise direction. The burnback is set correctly when the
welding wire does not stick to the work piece and does not melt
to the contact tip.
7) On-Off Switch
This switch controls the input power to your welder. The On-
Off switch allows you to turn the welding machine off, leaving
all the settings intact, ready for your next use.
Turning the switch to the ON position will illuminate an
indicator lamp in the On-Off switch and activate the cooling
fan. If the indicator lamp is not lit when the On-Off switch is in
the ON position, check to make sure that the machine is
properly connected to an electrical outlet in good working order.
Also be sure to check the fuse at the rear of the welder.
8) Welding Mode Switch
The welding mode switch lets you select between MIG “seam”
welding and “continuous” welding, lift arc DC TIG welding,
and stick welding.
MIG Seam Welding
The most common welding mode is the “seam” welding mode.
When you depress the trigger, the machine will weld, when you
release the trigger, the machine stops.
MIG Continuous Welding
The continuous welding mode is selected when welding long
seams and it is desired not to keep the trigger on the welding
gun depressed. Depressing the trigger and releasing it will
activate the welding machine. The welding machine will
continue welding until the trigger is depressed and released
again. This is very similar to a “lock-on” trigger on a drill or a
grinder.
TIG Welding Mode
When the MTS 160 is in the TIG welding mode, it is possible to
perform DC lift arc TIG welding of steel and stainless steel
material. The optional TIG welding torch must be attached to
the central adapter block on the front panel of the welder.
Stick Welding Mode
When the MTS 160 is in the stick welding mode, it is possible
to perform DC stick welding. Plug the optional electrode holder
into the positive output receptacle on the front of the unit for
electrode-positive (reverse polarity) stick welding and plug the
ground cable into the negative output receptacle.
Plug the optional electrode holder into the negative output
receptacle on the front of the unit for electrode-negative
(straight polarity) stick welding and plug the ground cable into
the positive output receptacle.
9) Amperage Adjustment (TIG and Stick Welding Modes)
Wire Feed Rate (MIG Welding Mode)
This knob has two different functions depending on the welding
mode.
In the TIG and STICK welding mode, this adjusts the welding
amperage of the machine. The higher the amperage, the thicker
the material you can weld. Minimum is 5 amps, 5 is 80 amps
and max is 160 amps. Use the following chart as a rough guide
for setting the amperage for TIG welding steel based on the
thickness of the material you will be welding.
Tungsten Welding Amp Filler
Thickness Diameter Amperage Setting Diameter
.030" .040" 30-40 2 .035"
.050" 1/16" 45-55 3 .035"
.062" (1/16") 1/16" 55-65 4 1/16"
.093" (3/32") 1/16" 80-90 5 1/16"
.125" (1/8") 1/16"-3/32" 110-120 7 1/16"
.187" (3/16")* 3/32" 130-140 9 1/16"
.250" (1/4")* 3/32"-1/8" 150-160 max 3/32"
In the MIG welding mode, this knob adjusts the wire feed rate.
The wire feed rate is infinitely adjustable and controls the wire
speed. Minimum is the slowest and maximum is the fastest.
The wire feed rate will depend on the wire diameter and the
welding voltage. The wire speed setting is tuned into the proper
welding sound. A hissing, blowing sound with a ball of molten
wire forming at the end of the wire and then dropping off
indicates the wire feed rate is too slow. A loud cracking noise
with the wire pushing the nozzle away from the work indicates
the wire feed is too fast. The proper wire feed rate is obtained
when a steady buzzing noise is heard while welding.
10) Voltage Adjustment
This knob controls the welding voltage in the MIG welding
mode. It is infinitely adjustable. The higher the welding
voltage the thicker you will be able to weld. Your MTS 160 will
let you weld from 24-ga steel up to 5/16" in mild steel.

11) Slope Down (TIG Mode) Arc Force (Stick)
In the TIG welding mode, this control adjusts the slope down.
The slope down is the amount of time it takes your MTS 160
to go from the preset welding current to off. A longer slope
down time will gradually cool your weld and help to prevent
“cratering”. The slope down is adjustable from .1 sec to 10 sec.
In the Stick welding mode, this control adjusts the Arc Force.
The arc force is how “hard” or “soft” the welding arc is. The
minimum setting produces a softer arc, while the maximum
setting produces a “harder” arc with more “driving” force
behind it. The “harder” arc may produce more spatter.
Front Panel Receptacles
1) Adapter Block
This is where the MIG welding gun or the TIG torch
connects to the machine. This single connection houses the
power, welding wire, shield gas, and the trigger wires.
To install the welding gun or TIG torch, simply insert the
male central adapter block (on welding gun) into the female
central adapter block (on welding machine). These will only
fit together in one way. Tighten the adapter nut securely
by hand.
2/3) Power Output Receptacles
3 is the positive power output receptacle and 2 is the
negative power output receptacle. These control the polarity
of the machine. For most MIG welding applications with
shield gas, the ground cable will be connected to the
negative receptacle (2). For most MIG welding applications
with flux cored wire and most TIG welding applications, the
ground cable will be connected to the positive receptacle (3).
If you have burn-through problems when welding on
extremely thin material with a solid wire and shielding gas,
you may want to reverse the polarity as this will reduce the
penetration and make it easier for you to weld thin material.
This is also where you will install your optional electrode
holder if you are arc welding. If you will be arc welding DC
electrode positive, then the electrode holder will go in the
positive receptacle (3) and the ground will be installed in the
negative receptacle (2). If you will be arc welding DC
electrode negative, then the electrode holder will go in the
negative receptacle (2) and the ground will be installed in
the positive receptacle (3).
When inserting the end of the ground cable into either
power output receptacle, secure the ground cable by twisting
it clockwise 1/2 turn. It is important that the ground clamp
be connected to a good, clean, surface. Failure to do so will
cause poor quality welds. Place the ground clamp as close
as possible to the area to be welded.
Polarity Adjustment
The polarity must be adjusted correctly for MIG welding with
shielding gas, flux cored MIG welding, and TIG welding. This
connection is located in the wire feed compartment. The wire
connected to the polarity terminal goes to the adapter block and
determines the polarity of the adapter block.
For most MIG welding applications using shielding gas, the
polarity wire will be connected to the positive terminal (1) as
shown. This would make the welding gun positive and the
ground cable would be plugged into the negative output
receptacle on the front of the welder (see Fig 3).
For most flux cored MIG welding and TIG welding, the polarity
wire will be connected to the negative terminal (2). This will
make the torch negative. The ground cable would be connected
to the positive output receptacle on the front of the welder (see
Fig 3).
To change the polarity from positive to negative, unplug the
welder from the power supply. Remove the insulated nut.
Remove the polarity wire from the positive terminal, and install
it on the negative terminal. Tighten the insulated nut securely
on the negative terminal.
6
Figure 3
Figure 2
1
23

7
1. Your MTS 160 is designed to use standard 8" diameter 10 lb
spools of welding wire. Remove the spool retaining nut (A)
from the wire drive brake. Place the wire on the spool holder
so it unravels from the bottom. Install the spool retaining nut
(A) and tighten.
2. Loosen the wire from the spool. Be extremely careful not to
let the end of the wire go. Cut off the bent end of the wire to
expose a piece of straight wire.
3. Swing the pressure release handle (1) down, and the pressure
roller assembly (3) will swing up and out of the way.
4. Install the guide tube (8), which is taped to the bottom of the
machine into the adapter block though the front of the
adapter block. See figure 2 page 6.
5. Feed the wire into the inlet wire guide (4), across the drive
roll (5), and into the guide tube (8). (At this time it is a good
idea to check that the drive roll is set to the correct groove
for the wire size you are using. If not, see Changing the
Drive Roll.) Continue to feed the wire into the guide tube
until two or three inches of straight wire protrudes from the
front of the central adapter block. Note that the drive roller
is designed to "float" on the shaft of the wire drive motor.
6. Swing the pressure roller assembly (3) back into position.
Make sure that the wire is positioned in the groove of the
drive roll (5). Unscrew the pressure release handle (1) until
most of the pressure on the pressure roller has been released.
7. Remove the contact tip and gas nozzle from the welding gun.
Turn the wire feed rate to 6. Depress the trigger on the
welding gun. At this point, the wire feed should not be
consistent because there is not enough pressure on the
pressure roller. Slowly tighten the pressure roller adjusting
screw until the wire feeds evenly without slipping. Then
tighten an additional 1/4 turn for steel. No additional
tightening is necessary for aluminum. DO NOT
OVERTIGHTEN!
Continue feeding the wire until it appears at the tip of the
welding gun. Check your wire size and install the correct
contact tip. Install the gas nozzle.
8. Next, the tension on the wire drive brake must be set
correctly. The wire drive brake keeps the spool of wire from
continuing to rotate after we have stopped welding. In the
center of the spool holder is a square plastic bolt (B) with
a slot for a large screwdriver. This plastic bolt puts tension
on a spring, which in turn puts tension on the shaft, acting
as a brake for the spool of wire. Set the wire feed rate to
maximum, adjust the tension on the wire drive brake so the
spool will continue to rotate 1/8 to 1/4 turn after you have
released the trigger. This can be adjusted by hand if the
spool retaining nut (A) is removed.
9. Bend the welding wire 90 degrees and hold the welding gun
perpendicular to a non-conductive surface (concrete floor) so
the wire will not feed. While looking at the wire feed
mechanism, momentarily depress the trigger. The drive roll
should slip and act as a clutching mechanism. If not, the
drive roll will push the wire out between the roller and the
guide tube. This is known as “bird nesting”. If bird nesting
occurs, the pressure roller has been adjusted too tightly.
When properly adjusted, the drive roll will slip, and “bird
nesting” will never occur.
Figure 4
Figure 6
Wire Drive
1) Pressure Release Handle
2) Drive Motor
3) Pressure Roller Assy
4) Inlet Wire Guide
5) Drive Roller
6) Drive Roller
Retaining Screw
7) Pressure Roller
8) Guide Tube
Figure 5
Spool Holder
A) Spool Retaining Nut
B) Drive Brake Tensioner
Feeding the Welding Wire
(See Fig. 4, 5, 6)
AB
12
3
58
6
4
7

8
SHIELD GAS - MIG WELDING
Since no flux is used for solid wire MIG welding, the proper
shield gas must be used. Different materials require different
shield gases. Use the chart below for a guide.
Material Shield Gas Flow Rate
Steel 75% Argon - 25% CO2 10 – 25 cfh
Aluminum 100% Argon 25 – 50 cfh
Stainless Steel 90% Helium + 7.5% Argon – 2.5% CO2 15 – 35 cfh
Brazing 100% Argon 15 – 35 cfh
Cast Iron 75% Argon - 25% CO2 25 – 35 cfh
Use a gas regulator such as HTP Part #12020 or a flowmeter
such as HTP Part # 12020F which is compatible with both
Argon and C-25 gas cylinders and has a barbed fitting for the
delivery hose. Connect the gas hose to the brass fitting at the
rear of the machine and to the barbed fitting on the regulator.
HTP also has available small 55 cubic foot gas bottles
(Part #99900), which are ideal for use with your welder. These
bottles stand approximately 30" high and weigh less than 40
pounds, making your welder very easy to move around the
shop. Be sure to check with your local gas supplier about
filling these tanks before ordering.
If you already have a large cylinder, you can fill the small
cylinder from the large cylinder using the transfer manifold
(HTP Part #99905).
NOTE: 75% Argon – 25% CO2 may be used for stainless steel
welding. Stainless steel can also be welded with steel wire and 75%
Argon – 25% CO2 gas, however, these welds will not be as corrosion
resistant as welds made with stainless steel wire.
SHIELD GAS - TIG WELDING
TIG welding requires the use of 100% argon shield gas for all
ferrous materials. The flow rate should be set at 20 to 30 cfh,
depending on the welding conditions.
MIG WELDING WITH YOUR MTS 160
Connect the MIG welding gun to the adapter block. Connect
the proper shield gas to the fitting at the rear of the unit and
adjust the flow to the correct setting. Plug the ground cable into
the negative receptacle.
There are two control points which have to conform: the power
setting (Volts) and the wire feed rate. The voltage setting is
determined by the thickness of the material which is being
welded (see Chart 3), and the wire feed rate is then “tuned in”
to the power setting. The correct setting of the power and the
wire feed rate can be seen in an even and calm arc and heard as
a steady frying noise.
When selecting your power setting, if the weld doesn’t appear to
be penetrating the metal, then turn up your power setting. If
you are burning a hole in what you are trying to weld, then it
will be necessary to turn down your power setting. If you are
on the lowest heat setting and still having problems with burn-
through, then you may want to reverse the polarity of your
welder. Use the following chart as a guide and fine-tune your
machine from there.
.023" Diameter Wire
Volt No Load Wire Feed Output Material
Setting Voltage Rate Amperage Thickness
2 18.0 1 1/2 24 24gauge
3 19.5 2 31 22 gauge
3 1/2 19.8 2 1/4 36 20 gauge
5 22.1 3 3/4 50 18 gauge
7 24.3 5 3/4 65 16 gauge
Max 28.2 Max 110 1/8"
.030" Diameter Wire
Volt No Load Wire Feed Output Material
Setting Voltage Rate Amperage Thickness
3 19.5 2 48 22 gauge
4 20.0 3 68 20 gauge
5 22.1 4 88 18 gauge
6 23.0 5 100 16 gauge
8 27.0 7 120 1/8"
9 28.0 8 135 3/16"
Max 28.2 Max 150 1/4"
12020
12020F
Gas
Bottle
Chart #3

9
A hissing, blowing sound with a ball of molten wire forming at
the end of the wire and then dropping off indicates the wire feed
rate is too slow (See Fig. X). This means that the wire is
melting before it reaches the metal. A loud, cracking noise with
red hot wire coming out of the gun and the wire pushing the
gun away from the work indicates the wire feed rate is too fast
(See Fig. Y). This means that the wire is melting beyond the
weld and is not melting properly. When “tuned in” properly, a
steady frying noise can be heard (See Fig. Z). This means that
the wire is melting properly, and is melting right at the surface
of the weld.
When tuning in your welding machine, it is best to start with the
wire feed rate too high. On the highest power setting, you may
actually want to start with the wire feed rate set at maximum.
Gradually decrease the wire feed rate until the steady frying
noise is heard. A common problem many people have when
trying to tune the wire feed rate is that they turn the knob too
rapidly. Many people never turn the wire feed rate down low
enough, and then start to increase it again. If the wire feed rate
is slowly decreased, then eventually you will cross the point
where the machine will be tuned in. It is a good idea to practice
tuning in the welding machine. Start with the Voltage setting at
#4, as it has a nice, crisp sizzle. Once you have mastered tuning
in the machine on Voltage Setting #4, practice tuning in the
machine on different Voltage Settings.
It is highly recommended that you practice with your welder at
different Voltage Settings so that you will become familiar with
your welder. This is important to do prior to welding on your
project so you will know which voltage setting to select for an
application.
SEAM WELDING
Install the conical nozzle (Part #15105) on the welding gun.
The conical nozzle is used because it is much easier to see the
welding process due to the taper in the nozzle. Have 1/4" to
1/2" of welding wire protruding from the end of the gas nozzle.
Prior to running a seam weld, it is recommended that tack welds
be placed every 2 to 3 inches along the seam, even closer for
extremely thin panels. Tack welds will help to hold the panel in
place while welding, as well as to prevent panel separation
caused by warpage.
Hold the welding gun at a 45-degree angle and use the edge of
the gas nozzle to hold the two panels together, aim the welding
wire at the spot to be tacked. Momentarily press the trigger
(approximately 1 second) and tack the two panels together. Do
not lift up the welding gun until the weld has set. Tack welding
is done at the same power setting at which seam welding is
done. Select the correct voltage setting based on Chart 3 for the
material you are welding.
When you have the panel tacked into place, you are ready to
seam weld. Once again, have 1/4" to 1/2" of welding wire
protruding from the gas nozzle. The welding gun is generally
held at a 45-degree angle to the work piece. It may also be
tilted at a 45-degree angle to the side. Rest the gun nozzle on
the work piece and have the wire pointing at the spot where the
welding is to begin. Press the trigger and begin welding. It is
important that you can see the welding wire coming out of the
gas nozzle and the small halo formed at the end of the welding
wire where it is melting. This halo will provide the light
necessary to see through your helmet while welding.
Figure x
Figure y
Figure z

10
The direction in which the welder travels will affect the
characteristics of the weld. When “pushing the weld” the
welding gun is tilted away from the direction of travel
(See Fig. 4). When “pulling the weld” the welding gun is tilted
toward the direction of travel (See Fig. 5).
As you gain expertise with your welder, you will find that is
possible to reduce warpage when welding sheet metal by
welding at a higher power setting and moving faster along the
seam. In this way, you are reducing the amount of time
welding, therefore reducing the amount of heat which is put into
the panel.
STITCH WELDING
Your HTP MTS 160 can perform a manual stitch weld. Stitch
welding refers to a method of welding where you will weld,
pause, weld, pause and continue in this cycle. This method
produces a welded seam which is actually a series of
overlapping spot welds that give the appearance of “Fish
Scales”. Stitch Welding is recommended for use on very thin
materials, such as thin body panels or rusty exhaust pipe and in
areas where it is desired to keep warpage to a minimum. Stitch
welding is also good for welders who have a problem keeping a
steady hand, or maintaining a constant travel rate.
Stitch welding is performed with the conical nozzle (15105),
small conical nozzle (15108), or the cylindrical nozzle (15104)
and the decision is up to the operator. For manual stitch
welding, the trigger on the welding gun is depressed until 3/16"
diameter puddle of metal is deposited on the workpiece.
Release the trigger and move the welding gun so that the center
of the next puddle will lie on the edge of the first puddle. Wait
for the orange glow from the first puddle to disappear and
deposit the second puddle of metal. Continue this process until
the seam is completed.
For a given thickness of metal, stitch welding is performed at
the same or one power setting lower than seam welding. Stitch
welding can be done on both steel and aluminum, and is
recommended under 120 amps. Stitch welding at higher power
settings can result in serious burnback problems.
SPOT WELDING
Install the spot weld nozzle (Part #15106) on the welding gun.
Using the Punch & Flange Tool (Part #12005 {5/16"} or
#12003 {3/16"}) or the Heavy Duty Hole Punch (#12009)
punch holes in the upper panel to be spotted on. Feed some
welding wire out past the end of the spot weld nozzle. Using
sidecutters, clip the welding wire off flush with the end of the
spot weld prongs. This will aid you in centering the gas nozzle
over the punched hole.
Select the correct voltage setting from the chart 3 (page 8) and
increase by approximately 2 numbers. Tune in the wire feed rate
until the proper frying noise is heard. Reduce the wire feed rate
just until the machine begins to sound out of tune. A slightly
slower wire feed rate will produce flatter spot welds for spot
welds which are vertical down, however, do not reduce the wire
feed rate when performing overhead spot welds. Place the
welding gun over the punched hole so that the welding wire is
centered over the punched hole (See Fig. 7). Depress the
trigger on the welding gun. Release the trigger as soon as the
hole is filled. Examine the spot weld. If the hole is not
completely full, either the welding wire was not centered over
the hole or the trigger was released too soon. If the spot weld is
Figure 5 “Pulling the Weld”
Figure 4 “Pushing the Weld”
Figure 6
“Stitch Welding”

11
not flat and has excessive metal build-up, then the trigger was
held too long, the wire feed rate is too fast, or the power is not
high enough. The correct power setting, welding time and wire
feed rate will produce spot welds which will lie flat and require
little, if any, finishing.
HOLE FILLING
Before you begin to fill holes, you must look at the reason why
there are holes. If the holes are due to burn-through, you
should remember that this was caused by too much heat input.
Therefore, if you are welding a seam and burn-through occurs,
continue welding and finish the seam. This will give the burn-
through area time to cool and make it easier to fill the hole. It
is not recommended to try to fill holes over 1/2" diameter; weld
in a new piece of metal.
First, the perimeter of the hole must be built up. This is
accomplished by randomly placing puddles of metal (similar to
manual stitch welding) around the perimeter of the hole (See
Fig. 8B). Once this has been completed, again place puddles
around the area which has just been welded (See Fig. 8C).
Continue to lay in the puddles until the hole is filled (See Fig.
8D & 8E). The voltage setting for hole filling is one to two
settings below seam welding.
WELDING ALUMINUM
It is possible to MIG aluminum with your MTS 160. Depending
on your application, you may be able to get away with pushing
aluminum welding wire through a 10ft welding gun, using our
aluminum welding kit #40011, or it may be necessary to use the
RSG250 spool gun. Pushing aluminum welding wire though a
10-ft. welding gun is not a foolproof situation. There is the
possibility the welding wire will bird’s nest while you are
welding. You have to determine when it makes economic sense
to invest in a spool gun. We generally recommend using the
standard 10’ welding gun if you would only be doing 1 small
repair job per month. If you are welding more aluminum than
that, you might want to consider the spool gun.
The RSG250 spool gun will allow you to get 25’ away from
your MTS 160. If you will be repairing aluminum trailers, the
spool gun is probably a must, as it will allow you to weld on the
trailer while leaving the MTS 160 and tank on the ground.
Since the spool gun has the wire and the drive roller right in
the handle, the wire is only getting pushed 6" and it is highly
unlikely that this gun would birdnest using any welding wire.
Due to the difference between aluminum and steel, a few simple
changes must be made prior to welding aluminum.
Shield Gas – The shield gas required for welding aluminum
is 100% Argon. Due to the rate at which aluminum oxidizes,
the flow rate of the Argon gas must be increased to 25 cubic
feet per hour (cfh) or more. The cylindrical gas nozzle (Part
#15104) is recommended for use on the standard welding gun
when welding aluminum. The larger opening area of the nozzle
will result in a wider dispersion of the shield gas, insuring
adequate gas coverage of the weldment.
Figure 7
“Spot Welding”
Figure 8 “Hole Filling”
ABCD E
40011
Aluminum Kit
RSG 250

12
Liner – A Teflon liner (part #15044) is the preferred liner for
welding aluminum. To change the liner, see “Testing and
Changing the Liner”.
Welding Wire – To weld aluminum, aluminum welding wire
must be used. HTP has aluminum wire available in two
diameters; Part #40230 - .030" diameter and Part #40235 -
.035" diameter. The .030" wire is recommended for thin gauge
to 1/8" material, while the .035" is recommended for .060"
material and thicker. For installation of the aluminum wire, see
"Feeding the Wire."
Cleanliness – Aluminum is very sensitive to impurities.
Therefore, it is extremely important that the surfaces to be
welded are clean from paint, grease and dirt. The only method
that will properly clean aluminum is the use of a stainless steel
wire brush (Part #40112 or #40110).
Technique – Aluminum also requires a slightly different
technique when welding. The gas nozzle should be held
perpendicular to the welding surface and inclined 5 to 15
degrees away from the direction of travel. The motion of the
welding gun should be consistent and at a greater speed than
used for welding steel. To minimize the chances of producing
a black, sooty weld, you should always “Push the Weld”.
Aluminum will require a much higher wire feed rate than steel
for the same heat setting and same wire diameter.
Aluminum also has a very narrow heat range in which it can be
welded. When you first start to weld, you will notice the weld
has a tendency to sit up on top of the metal and not penetrate.
If you keep welding you may see that it begins to penetrate fine
and you will get a great weld. As you continue to welding, all
of the sudden, you have overheated the metal and blow a big
hole. This is one of the problems of welding aluminum and just
requires practice to overcome.
The end of the welding wire should always be clipped off with
side cutters to aid in striking the arc.
The thermal conductivity of aluminum is much higher than
that of steel. Therefore, when welding thin gauge aluminum
a heat sink (HTP’s Heat Sponge, Part #12080) should be used.
Aluminum hoods and trunk lids may require the stitch welding
technique if burn-through is a problem.
The tendency for aluminum spatter to adhere to the swan neck,
contact tip and gas nozzle is much greater than that for steel.
Therefore, use of the nozzle spray is extremely important.
However, the nozzle spray will act as a contaminant, so after
treating the nozzle, it is important to test weld on a piece of
scrap aluminum to "burn off" the nozzle spray.
When welding thick sections of aluminum (Cylinder Head),
many times it is helpful to preheat the area with an oxy-
acetylene welding torch. Using a rosebud tip set the torch
acetylene rich and blacken the area to be welded with a light
coat of soot. Set the torch correctly, and begin to evenly heat
the part. Let the heat within the part (not the torch) burn off the
soot. When the soot has burned off, the part has been
sufficiently preheated.
CAUTION – Aluminum does not change color when hot.
STUD WELDING
With the purchase of the optional DENT PULLER KIT (Part
#12015), your MTS 160 Welder makes it possible to pull dents
without drilling holes in the dented panel. The dent puller kit
comes complete with one stud weld nozzle (Part #15007), one
box of 500 studs (Part #12038) and a special slide hammer.
Install the stud weld nozzle on the welding gun. Set the voltage
to 5, 6, 7, or 8 depending on the thickness of the material. Tune
in the wire feed rate to the proper setting. Invert the welding
gun and insert a stud in the tube protruding from the gas nozzle.
The head of the stud will prevent the stud from falling out of
the nozzle.
Grind away paint and rust from dented area to be pulled. Place
welding gun against dented area so that the stud will be welded
in the desired position. Place your finger over the end of the
stud protruding from the nozzle so that the stud comes in
contact with the dented panel. Depress the trigger on the
welding gun while maintaining pressure on the stud. The stud
will begin to melt. Continue welding until your finger has
reached the gas nozzle and no more stud can be pushed into
the panel. Allow the weld to cool. Remove gas nozzle from
the stud.
Install the slide hammer on the stud. Pull the dent. After the
dent has been pulled, remove the stud from the slide hammer.
The stud may be removed from the dented panel by grinding,
clipping off with side cutters, or simply bending it from side to
side until it snaps off.

13
WELDING MUFFLER PIPE
Muffler pipe welding is generally done with the conical nozzle
installed on the welding gun. The conical nozzle is used
because the taper in the nozzle makes it easier to see the
welding process and allows you to weld in tighter spots.
Prior to welding two pieces of muffler pipe together, it is
recommended that two to three tack welds be placed around the
pipe. The tack welds will help hold the pipe in place while
welding, and also prevent gaps caused by warpage.
Have 1/4" to 1/2" of welding wire protruding from the end of
the gas nozzle. Have the welding gun inclined at a 45-degree
angle to the pipe. Aim the welding wire at the spot to be tacked
and momentarily depress the trigger. Hold the trigger long
enough for the welding sound to smooth out (approximately one
to two seconds). Since exhaust tubing is generally 16 ga tubing,
the voltage setting will be between 6 and 7. (See chart 3)
Now that the pipe is tacked into place, you are ready to weld the
pipe. Once again, have 1/4" to 1/2" of welding wire protruding
from the gas nozzle. Again, the welding gun is generally held at
a 45-degree angle to the pipe. It also may be tilted at a 45-angle
to the left or right. Rest the gas nozzle on the pipe and have the
wire pointing at the spot where the welding is to begin. Press
the trigger to begin welding. Slowly move the welding gun
along the weld at a constant rate. A jerky, inconsistent, or too
rapid rate will cause arc instability and a sputtering welding
sound. A rate that is too slow will cause burn-through. It is
also important that you position the welding gun so that you can
see the welding wire as it comes out past the gas nozzle. The
light produced from the wire coming in contact with the work is
the only thing that will allow you to see the "seam" through the
welding helmet. If the gas nozzle is blocking your view of the
wire, then there will not be sufficient light to see the welding
process.
HTP has a flexible swan neck welding gun available (Part
#13510) available for welding muffler pipe. The flexible swan
neck makes it possible to bend the swan neck to get into hard to
reach places and to get up over the top of the muffler pipe.
BROKEN STUD REMOVAL
Your HTP MTS 160 can be used to remove exhaust manifold
studs which have broken off flush or are protruding slightly
from the exhaust manifold. In many instances, it is not even
necessary to remove the exhaust manifold from the car.
Start with the voltage at 7 or 8. This will ensure good adhesion
of the molten wire to the stud. Point your wire directly at the
stud and momentarily depress the trigger. Weld long enough to
deposit a small puddle of molten wire on the stud and then
allow it to cool. Repeat the process until you have built up a
small puddle of molten wire on the stud and allow it to cool.
Repeat the process until you have built up a small amount of
weld. Reduce the voltage to 4 or 5 and continue building the
weld until 1/4" to 1/2" is protruding from the exhaust manifold.
The lower power setting will allow you to build up the weld
faster. Now take a 5/8" or 3/4" nut and place it on the stud.
Allow the stud to cool completely. Heat the exhaust manifold as
you normally would and remove the stud. Shops have proven
this process works 80% of the time.
WELDING CAST IRON
Your HTP MTS 160 has the ability to weld cast iron using 75%
Argon – 25% CO2 shielding gas and cast iron welding wire
(Part #50235). The cast iron welding wire will also allow you to
weld mild steel to cast iron. However, the preferred method for
welding cast iron would be TIG welding. This MIG filler,
although thin, works excellent as a TIG rod for cast iron.
When welding with the cast iron wire, welding techniques are
the same as the welding techniques for mild steel. Due to the
.035" diameter, wire feed rates for cast iron welding wire will be
lower for a given power setting than the .030" diameter steel
wire. However, the machine is tuned in the same way as with
the steel wire, listening for the “sizzling” noise.
Muffler Pipe
Flex Neck

14
Depending on the thickness of the material, it may be desirable
to preheat the casting to ensure adequate penetration. When
welding a crack, it may be beneficial to “vee” out the crack. In
order to reduce the possibility of further propagation, drill
small holes at both ends of the crack. It is also a good idea to
make short welds to reduce the possibility of overheating the
cast iron around the weld area. Then immediately after
welding, lightly tap (peen) the weld with a ball-peen hammer to
stress relieve the weld area.
The more time spent in surface preparation of cast iron welds
(cleaning the surface, veeing out cracks, etc.) the better the
results and the stronger the weld will be.
TIG WELDING WITH YOUR MTS 160
In order to TIG weld, remove the MIG welding gun from the
MTS 160 and install the optional TIG welding torch (Part #
SR17-12.5MTS) on the machine. Generally speaking, except
for very rare instances, you will TIG weld DCEN, or DC
electrode negative. If you were MIG welding with shielding
gas, you will have to change the polarity from electrode positive
to electrode negative. (See page 6, Polarity Adjustment)
Plug the ground cable into the positive output receptacle.
Use 100% argon shielding gas.
Setting Up The Torch
Lets assume we will be welding some .060" mild steel.
Selecting a 1/16" 2% Ceriated tungsten, we grind a point on the
end of the tungsten (remember always grind the tungsten
longitudinally, never radially). Select a 1/16" collet and insert
the tungsten so the pointed end of the tungsten comes out
through the slit in the collet. Next insert the collet/tungsten
assembly into the threaded end of the collet body, so the pointed
end of the tungsten comes out through the sized hole of the
collet body. (See Fig 8A) Thread the assembly into the torch
head and tighten the collet body snugly by hand. Install the
back cap, but do not tighten at this point. Install a #6 alumina
cup on the collet body and tighten snugly by hand. Have the
tungsten protruding from 2 to 3 times its diameter from the end
of the cup (in this instance 1/8" to 3/16" (See Fig 8B). Tighten
the back cap.
Holding The Torch
It is recommended that you use TIG welding gloves like our
BL25 gloves. These are thinner than standard welding gloves
and will give you a much better “feel” and make it easier to
work the filler rod. Grip the torch somewhat like a pencil, as
indicated in figure 8C. The torch must be positioned almost
perpendicular to the work and in such a manner that the
tungsten is kept 1/8" to _" off the work. The tungsten should
only contact the work when starting the arc. Once the arc is
started, the tungsten should never contact the work. Use the
edge of your hand and little finger to hold the torch steady.
Set the amperage to about 60 amps (#4 on the amperage
selector). Connect argon to the machine and set the flow rate to
about 20 cfh. Push the trigger switch to start the current flow.
Gently touch the tungsten electrode to the work and then lift it
off the work. HTP’s touch start circuitry will start the arc.
Initially, just practice moving the tungsten in a straight line, at a
constant speed, and keeping it a constant distance off the work
piece. Remember that Rome wasn’t built in a day, so don’t
expect to master TIG welding in 15 minutes. PRACTICE,
PRACTICE, PRACTICE.
Once you have mastered just running a bead in a straight line
without adding any filler metal, the next step is to do the same
thing but to add filler metal. Dip the filler metal into the molten
puddle (do not try to melt the filler metal into the work) and
NEVER allow the filler metal to touch the tungsten. If the filler
metal comes in contact with the tungsten, or if the tungsten
contacts the work, you must stop and sharpen the tungsten.
Remember, practice, practice, and practice.
To make my life easier, and so I am not always stopping to
sharpen tungsten, I keep a package of 10 tungsten of each
diameter sharpened in the box. That way, when I need a new
tungsten, I can just take a sharp one and put the contaminated
one in the box. When I have used them all, I will sharpen them
all at once.
Now, once you have practiced laying a bead and adding filler
metal, then you can practice welding two pieces of metal
together. Start with a butt weld, as this is the easiest. Master
this technique before you continue to other joints. Compared to
MIG welding, TIG welding is much harder and will require a lot
of practice to become proficient.
Figure 8C
Figure 8B
Figure 8A

General Welding Parameters
Following are some “rule of thumb” welding parameters,
tungsten diameters and amperage settings for welding different
thicknesses of steel. Keep in mind these are general settings
and the specific application may require more or less power to
get the job done.
Steel
Tungsten Welding Filler
Thickness Diameter Amperage Diameter
.030" .040" 30-40 (2) .035"
.050" 1/16" 45-55 (3) .035"
.062" (1/16") 1/16" 55-65 (4) 1/16"
.093" (3/32") 1/16" 80-90 (6) 1/16"
.125" (1/8") 1/16" 110-120 (71/2) 1/16"
.187" (3/16")* 1/16"-3/32" 130-140 (9) 1/16"
.250" (1/4")* 3/32" 150 (Max) 3/32"
* May require beveling – depends on joint
Filler Rod for TIG Welding
HTP offers you high quality filler rods in affordable quantities.
All filler rod is packaged in 1lb airtight plastic tubes to keep
your filler rod fresh and contaminant free. The tubes are
completely re-sealable.
In TIG welding, the filler rod is fed into the molten puddle by
hand. The choice of filler rod is extremely important as the rod
must correctly match the material and alloy you will be welding.
The thickness of the material to be welded determines the
diameter of the filler rod.
Tungsten Electrodes
HTP recommends the following premium quality tungsten
electrodes ground to a high quality finish for use with your
MTS 160. All tungsten is 7" long and can be purchased
individually.
2% Thoriated Tungsten (TT2) – red tip - This tungsten is the
most common tungsten currently used. Generally used for DC
welding of steel and stainless steel. Draw back is it has a low
level radiation hazard. Offers good overall performance.
2% Ceriated Tungsten (TC2) – grey tip – 2% Ceriated is an
excellent substitute for 2% thoriated tungsten and works
excellent with inverter power sources such as your 160DC.
More popular for thinner materials because it requires less
amperage to start. Offers a stable arc.
2% Lanthanated Tungsten (TL2) – blue tip – 2% lanthanated is
also an excellent substitute for 2% thoriated tungsten. It offers
good arc starting characteristics and longer life than 2%
thoriated.
Tungsten Type Diameter
.040" (1.0mm) 1/16" (1.6mm) 3/32" (2.4mm) 1/8" (3.2mm)
2% Thoriated TT2-7040 TT2-7116 TT2-7332 TT2-718
2% Ceriated TC2-7040 TC2-7116 TC2-7332 TC2-718
2% Lanthanated TL2-7040 TL2-7116 TL2-7332 TL2-718
Amperage 15-50 50-120 80-150 130-250
The electrode should be sharpened to a point with a fine
grinding wheel. If the stone used for sharpening the electrode
is not clean, contaminants could lodge in the electrode and
dislodge when welding. The grinding wheel used for tungsten
electrodes should not be used for any other materials. When
grinding the electrode to a point, a 15 to 30 degree angle is
desired. The grinding marks should run lengthwise with the
point, opposed to in the direction of the diameter.
The HTP Tungsten Sharpener is an excellent tool for precisely
sharpening tungsten electrodes without any fear of
contamination.
HTP
Tungsten Sharpener 15
HTP
Filler Rod

MAINTENANCE AND SERVICE
Introduction
90% of the problems with MIG welders are wire feed/welding
gun related. 98% of these problems are due to owner/operator
abuse, misuse or ignorance.
The welding gun is exposed to the heat and spatter of welding.
The NOZZLE SPRAY (Part #12021) should be sprayed on the
inside of the gas nozzle, contact tip and swan neck with every
use. The function of the nozzle spray is to prevent the spatter
from adhering to the gas nozzle, contact tip and swan neck,
making it easy to keep these parts clean. However, using the
spatter spray does not eliminate the need to frequently clean the
spatter from the gas nozzle. For this reason, HTP has available
a NOZZLE REAMER (Part #12025). The nozzle reamer
makes it very easy to keep your tips and nozzles clean.
Figure 9 shows the early symptoms of spatter build up. The
exterior of the nozzle has arc marks on it from shorting out.
You will also notice the nozzle sticking to the work and
inconsistent weld quality when the nozzle shorts out.
Figure 10 shows a cutaway of a nozzle with spatter build up.
This nozzle is ruined because the operator allowed the spatter to
build up excessively, so the spatter has now welded itself to the
inside of the gas nozzle.
Here are some good rules of thumb to help you select the
correct filler metal:
1) ER70S-6 is generally used for mild steel welding.
2) ER70S-2 is highly recommended for welding 4130
chrome-moly tubing in many applications.
3) ER80S-D2 is recommended for welding 4130 chrome-moly
tubing if a higher strength, less ductile weld is required. If
your weld will be heat treated to obtain optimum strength,
then use a filler metal which matches the chemistry of your
tubing, which neither 70S-2 nor 80S-D2 wires do.
4) Generally speaking, use a 1/16" diameter filler rod for
applications where the material is 1/8" and less. Use a 3/32"
diameter rod for 1/8" and thicker.
The following Filler Rod is available from HTP in 1 lb. tubes
which are tightly sealed to prevent oxidation.
Filler Rod
Part # Material
308L-035-1 308L Stainless Steel Wire - .035" x 36"
308L-1/16-1 308L Stainless Steel Wire 1/16" X 36"
70S6-1/16-1 ER70S-6 Steel Wire 1/16" X 36"
70S6-3/32-1 ER70S-6 Steel Wire 3/32" X 36"
70S2-1/16-1 ER70S-2 Steel Wire 1/16" X 36"
80SD2-1/16-1 ER80SD-2 Steel Wire 1/16" X 36"
Nozzle Reamer
16
ARC WELDING WITH YOUR MTS 160
You can arc weld with your MTS 160 if you have purchased the
optional electrode holder # 22315-ARCMTS. If you will be
welding Electrode Negative (Straight Polarity) insert the
electrode holder into the negative output receptacle and the
ground cable into the positive output receptacle. If you will be
welding Electrode Positive (Reverse Polarity) insert the electrode
holder into the positive output receptacle and the ground cable
into the negative output receptacle.
Make sure material you are
welding is clean, and attach the
ground cable to the workpiece.
Select the correct rod type,
diameter and amperage for
your application. (See Chart E1)
To strike the arc, drag the
electrode across the work as if
you were trying to strike a match.
Lift the electrode off the work
slightly. If the electrode sticks to
the work, give it a sharp twist to
break it free. If the arc goes out
after it has started, you have lifted
the electrode too high off the
work. Try to incline the electrode
at a 10 deg to 30 deg angle from
perpendicular in the direction of
motion.
40 50 60 70 80 90 100 110 120 130 140 150
6010 EP DEEP ALL 3/32"
1/8"
5/32
6011 EP DEEP ALL 3/32"
1/8"
5/32
6013 EP,EN LOW ALL 3/32"
1/8"
5/32
7014 EP,EN MEDIUM ALL 3/32"
1/8"
5/32
7018 EP LOW ALL 3/32"
1/8"
5/32
7024 EP,EN LOW FLAT 3/32"
1/8"
308L EP LOW ALL 3/32"
1/8"
5/32
Electrode Selection and Amperage Range
Amperage Range
Electrode
Polarity
Penetration
Position
Diameter
Chart E1

Figures 11 and 12 show what will happen to the swan neck
if you do not keep your nozzle clean. Both figures illustrate
that in extreme cases, shorting out the nozzle will burn holes
completely through the swan neck requiring its replacement.
In Figure 11 is a deformed nozzle spring pointing outward, so it
will come in contact with the inside of the gas nozzle. In Figure
12, the nozzle spring is wound down around the base of the
swan neck. These deformed springs are caused by improper
removal of the gas nozzle. This again will cause the welding
current to be transmitted to the exterior of the gas nozzle, once
again causing a short circuit. THE NOZZLE CAN ONLY BE
REMOVED BY TWISTING IN A CLOCKWISE DIRECTION
WHILE PULLING IT OFF.
Figure 9
Spatter Build Up Symptoms
Figure 10
Spatter Build Up
Figure 11
Spatter Damaged Swan Neck
Figure 12
Spatter Damaged Swan Neck
Figure 16 shows the effect of a wire drive mechanism that has
been set just a little bit too tight. As you can see, the wire has
been spiraled into the liner, resulting in the curvy wire. When
the wire got to the contact tip, it could not pass through the
contact tip smoothly, hence burning back to the tip. Since the
wire could not pass through the tip, this same situation
(spiraling wire) has now occurred at the other end of the
welding gun. When it passes 10 feet through the welding gun,
the wire will not be able to pass through the tip smoothly. If
resetting the tension on the drive roller does not remedy this
problem, then the liner should be replaced.
CHANGING THE CONTACT TIP
The contact tip should be regarded as a wearing part and
therefore requires periodic replacement. Since steel wire is
passing through a copper tip, the wire will have a tendency to
wear away the copper tip, causing it to become oblong or
excessively oversized. This one-inch piece of copper is all that
is taking the welding amperage and transferring it to the
welding wire. Therefore, an excessively worn tip will cause
poor electrical contact between the wire and the tip, resulting in
a welder that will not weld smoothly.
To remove the contact tip, clip off the burnt wire at the end of
the welding gun. Unscrew the contact tip. Install the new tip by
feeding the wire through the hole in the center of the tip and
screw the tip into the swan neck.
Part # Fits Wire Size
15023B .023" 0.6 mm
15030B .030" 0.8 mm
15035B .035" 0.9 mm
15040B .040" 1.0 mm
15045B .045" 1.2 mm
CHANGING THE GAS NOZZLE
The gas nozzle is removed by simultaneously twisting the gas
nozzle and pulling it off. The gas nozzle can only be twisted in
a clockwise direction. Twisting the nozzle in a counter-
clockwise direction will damage the nozzle spring. To install
the gas nozzle, simply twist the nozzle in the same clockwise
direction while pushing it on the swan neck. The following gas
nozzles are available for your welding gun:
Part # Description Application
15105B Conical Nozzle General Welding
15004B Cylindrical Nozzle Aluminum Welding
15106B Spot Weld Nozzle Spot Welding
15108B Small Conical Nozzle Corner Welding
17
Figure 16

SETTINGTHE PRESSURE ON THE PRESSURE ROLLER
Prior to readjusting the pressure roller, check the following:
1. Are the drive roller and pressure roller clean? If not, clean
with a suitable solvent.
2. Is the liner worn, dirty or kinked, causing a restriction to the
wire feed? (See testing and changing the liner.) If so,
replace the liner.
3. Is the guide tube lined up properly with the drive roll?
If not, align the guide tube.
4. Is the guide tube coming in contact with the drive rolls?
If so, remove the guide tube and shorten it by grinding.
If all of the above mentioned conditions are in good working
order, then it may be necessary to reset the pressure on the
pressure roller.
1. Loosen the pressure roller adjusting screw (1), pull the
pressure release handle (1) out of the way and lift the
pressure roller assembly (3) up and out of the way.
2. Loosen the wire from the spool. Feed the wire into the inlet
wire guide (4), across the drive roll (5) and into the guide
tube (8). Check to be sure that the groove in the drive roll is
the correct groove for the wire diameter you are using. Feed
the wire until two or three inches of straight wire protrudes
from the central adapter block.
3. Swing the pressure roller assembly (3) back into position,
making sure the wire is positioned in the groove of the drive
roll (5). Tighten the pressure roller adjusting screw just
enough to keep the wire in the groove. DO NOT
OVERTIGHTEN!
4. Insert the wire protruding from the central adapter block into
the end of the welding gun. Install the welding gun on the
welding machine.
5. Remove the contact tip and gas nozzle from the welding
gun. Turn the wire feed rate to 6. Depress the trigger on the
welding gun. At this point, the wire feed will be inconsistent
because the majority of tension has been removed from the
pressure roller. Slowly tighten the pressure roller adjusting
screw until the wire feeds evenly without slipping. Then
tighten an additional 1/4 turn for steel. No additional
tightening is necessary for aluminum. DO NOT
OVERTIGHTEN!
Continue feeding the wire until it appears at the tip of the
welding gun. Check your wire size and install the correct
contact tip. Install the gas nozzle.
6. Bend the welding wire 90-degrees and hold the welding gun
perpendicular to a non-conductive surface (concrete floor)
so that the wire will not feed. While looking at the wire feed
mechanism, momentarily depress the trigger. The drive roll
should slip and act as a clutching mechanism. If not, the
drive roll will push the wire out between the roller and the
guide tube. This is known as “bird nesting.” If bird nesting
occurs, the pressure roller has been adjusted too tightly.
When properly adjusted, the drive roll will slip, and “bird
nesting” will never occur.
18
Figure 6
Wire Drive
1) Pressure Release Handle
2) Drive Motor
3) Pressure Roller Assy
4) Inlet Wire Guide
5) Drive Roller
6) Drive Roller
Retaining Screw
7) Pressure Roller
8) Guide Tube
1
3
58
6
4
7
2

CHANGING THE DRIVE ROLL
The drive roll has two grooves on it. The narrower of the two
grooves is marked 0.6 and is used for .023" wire. The wider
groove, marked 0.8, is used for .030" wire.
To change the drive roll, simply remove the drive roll retaining
screw (6) and remove the drive roll (5) from the adapter ring.
Select the correct groove, and install the drive roll so that the
proper groove lines up with the inlet wire guide (4) and the
guide tube (8). Install drive roll retaining screw.
TESTING AND CHANGING THE LINER
Should feeding problems occur, the first item to be check should
be the liner. The following check should be made to determine
if the line is defective:
1. Feed 12’ to 18" of fresh wire out of the welding fun.
(See Fig. 17)
2. Disconnect the welding gun from the machine with the wire
still threaded in the gun. Pull the gun 6" away from the
machine and clip the wire so that 6" of the wire is extending
out of the welding gun. (See Fig. 18)
3. Push the wire in and out of the welding gun as shown in
Fig 19. The wire should move freely in the gun with little or
no resistance. If there is a great deal of friction, the liner
should be replaced.
To replace the liner, remove the liner positioner nut with a
12mm wrench and pull the old liner completely out of the
welding gun. (See Fig. 20) Remove the gas nozzle and contact
tip. If installing a Teflon liner, install the collet on the liner.
Slowly push the new liner into the welding gun. (See Fig. 21)
Be careful not to try to push too much liner into the gun at one
time, or the liner may kink. Lay the welding gun out straight
and install the liner positioner nut. Clip the excess liner off
flush with the end of the swan neck. Use a razor blade on Teflon
liners. (See Fig. 22) Coil the welding gun, and cut an additional
1/8" to 3/16" from the liner. Install the correct size contact tip.
Part # Description
15040 Steel liner - for flex neck or standard swan new -
steel welding only
15044 Teflon liner - for flex neck or standard swan neck -
aluminum welding only
19
Figure 17 Figure 18
Figure 21
Figure 22
Figure 19
Figure 20

WELDING WIRE
HTP has a wide variety of welding wire available. For
autobody repair, we strongly recommend the following wires:
Application Part # Description
Steel 21023 .023" E70S-6 Steel wire
Aluminum 40230 .030" 5356 Alloy Aluminum Wire
We are typically finding body panels being made from 22 gauge
(.0299" thick), 24 gauge (.0239" thick) and 26 gauge (.0179"
thick) steel. When welding this thin metal, the secret to
minimizing distortion and burn-through is by using a wire
which will require the least amount of heat to melt. This would
be the thinnest wire available, .023" diameter in steel and .030"
diameter in aluminum.
For muffler work and general repair welding, we are generally
working on thicker materials. We therefore recommend using
part #21030, .030" steel wire. This wire will give greater
penetration and less feeding problems.
Application Part # Description
Steel (30 ga -1/8") 21023 .023" E70S-6 Steel Wire
Steel (16 ga - 1/4") 21030 .030" E70S-6 Steel Wire
Steel (14 ga -1/2") 21035 .035" E70S-6 Steel Wire
Aluminum (24 ga -1/8") 40230 .030" 5356 Alloy Aluminum Wire
Aluminum (16 ga - 1/4") 40235 .035" 5356 Alloy Aluminum Wire
Stainless Steel (24 ga -1/8") 38223 .023" Stainless Steel Wire
Stainless Steel (18 ga -1/4") 38230 .030" Stainless Steel Wire
Cast Iron 50235 .035" Cast Iron Wire
Brazing 50230 .030" Silicon Bronze Wire
Steel W/O Gas (16 ga -1/4") 61030 .030" Flux cored Wire
Steel W/O Gas (16 ga -1/4") 61035 .035" Flux Cored Wire
For other applications, use the following chart as a guide:
All HTP steel welding wires are AWS grade E70S-6. This is a
high quality welding wire with additives to reduce spatter and
offer better wetting characteristics on rusty material. Also, this
is the only grade of welding wire that is compatible with the
High Strength Low Alloy steels found in today’s unibody
vehicles.
20
MONTHLY MAINTENANCE
Your HTP MTS 160 is a very hardworking piece of equipment
and is very simple to maintain. However, your HTP MTS 160
is more complicated than other types of welding equipment.
It is very important that these simple maintenance procedures
be followed to keep your welder operating trouble free.
1. Wire Drive System – The guide tube and inlet wire guide
should be check periodically to ensure that they are in correct
alignment with the drive rolls. Misalignment will result in
the copper plating of the wire being rubbed off. This copper
dust will be carried into the liner resulting in increased
friction causing wire feed problems.
2. Welding Cable – You should not allow heavy equipment to
run over the welding cable. Avoid pulling the machine by
the cable.
Do not pull the welding cable over sharp edges.
3. Transformer and Internal Components
Your MIG Welder is equipped with a thermoswitch to protect
the internal components of you welder should the duty cycle
be exceeded. The thermoswitch is placed in the low voltage
circuit, so that when the duty cycle is exceeded, the main
relay will not operate, preventing power from going to the
main transformer. The indicator light will remain on, the
wire will not feed, and on the machines equipped with
cooling fans, the fans will remain on. When the machine
cools down (approximately 20 minutes) the thermoswitch
will automatically reset itself and the machine will be ready
for use.
To keep the cooling system of your welder operating at peak
performance, it is necessary to remove the side panel and
blow this area out with dry, compressed air. This will
remove dirt and dust from the internal components.