Taylor 800DA User manual

V-21A
OPERATING GUIDE
FOR
TYPE 800DA
DRAWN ARC CONTROLLER
TAYLOR STUDWELDING
SYSTEMS LIMITED

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INDEX
2
PAGE No. CONTENT
3 USEFUL INFORMATION.
5 IMPORTANT SAFETY INFORMATION.
7 INTRODUCTION TO STUDWELDING.
8 GUIDE TO EXTERNAL FEATURES.
11 SETTING UP AND WELDING.
14 WELDING TIME AND CURRENT SETTINGS.
15 VISUAL WELD INSPECTION.
16 WELD TESTING.
19 STUDWELDING TECHNIQUES.
22 PARTS LIST & EXPLODED DIAGRAMS.
29 CIRCUIT SCHEMATIC - WIRING.
30 CIRCUIT SCHEMATIC - DISPLAY PCB.
31 ACCESSORIES.
32 DECLARATION OF CONFORMITY.

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USEFUL INFORMATION
3
MANUFACTURERS DETAILS
TAYLOR STUDWELDING SYSTEMS LIMITED
COMMERCIAL ROAD
DEWSBURY
WEST YORKSHIRE
WF13 2BD
ENGLAND
TELEPHONE : [phone]
FACSIMILE : [phone]
email : [e-mail]
WEB : www.taylor-studwelding.com
SALES DIRECT TEL : [phone]
TECHNICAL HELPLINE : [phone]
You may wish to record the details of your controller below as this information will help
with any technical assistance you may require:
PURPOSE AND CONTENT OF THIS GUIDE
This guide has been written for :
• The personnel of the end-user responsible for the installation and maintenance of the
controller.
• The operator of the welding controller.
This guide contains information relating to :
• Installation and connection.
• Operation.
• Technical specifications and parameters.
• Spare parts.
CONTROLLER SERIAL No.
DATE PURCHASED.

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USEFUL INFORMATION
4
FURTHER INFORMATION
Should you require additional technical information, please contact us directly
(details on previous page) or our local agent / distributor (details of agents etc. can be
obtained from us).
This guide contains important information which is a pre-requisite for safe Operation
of the equipment. The operating personnel must be able to consult this guide when
necessary. In the interests of safety, make this guide available to your personnel in good
time.
If the equipment is sold / passed on, please hand over this manual to the new owner
and if possible please inform us of the name and address of the new owner, in case we
need to contact him regarding the safety of the machine.
PLEASE READ THIS GUIDE CAREFULLY BEFORE INSTALLING OR OPERATING
THE CONTROLLER.
PLEASE OBSERVE CAREFULLY ALL SAFETY PROCEDURES/INSTRUCTIONS.
DUE TO THE POWER REQUIREMENTS AND ELECTROMAGNETIC EMISSIONS
PRODUCED DURING NORMAL USE, THIS MACHINE MUST ONLY BE OPERATED
IN AN INDUSTRIAL ENVIRONMENT.
THIS MACHINE OPERATES FROM A MAINS SUPPLY OF 380/415V AC @ 50/60 Hz
NEVER REMOVE ANY PORTION OF THE UNIT HOUSING WITHOUT FIRST
ISOLATING THE CONTROLLER FROM THE MAINS ELECTRICAL SUPPLY.
NEVER OBSTRUCT THE UNDERSIDE, FRONT OR REAR PANELS AS THIS MAY
CAUSE THE UNIT TO OVERHEAT DURING OPERATION.
DO NOT USE THIS WELDING POWER SOURCE FOR PIPE THAWING.
THIS EQUIPMENT HAS BEEN EMC TESTED AND APPROVED IN ACORDANCE
WITH BS EN 60974-10 (CATEGORY 2).
Taylor Studwelding Systems Limited reserves the right to amend the contents of this guide without notification.

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IMPORTANT SAFETY INFORMATION !
5
PROTECT YOURSELF AND OTHERS !
Read and understand these safety notes.
1. ELECTRICAL
No portion of the outer cover of the welding controller should be removed by anyone other
than suitably qualified personnel and never whilst mains power is connected.
ALWAYS DISCONNECT THE MAINS LEAD BEFORE ATTEMPTING ANY MAINTENANCE.
BEWARE - RISK OF ELECTRIC SHOCK !
Do not use any fluids to clean electrical components as these may penetrate into the
electrical system.
Installation must be according to the setting up procedure detailed on page 11 of this guide
and must be in line with national, regional and local safety codes.
2. FIRE
During welding small particles of very hot metal are expelled. Ensure that no combustible
materials can be ignited by these.
3. PERSONNEL SAFETY
Arc rays can burn your eyes and skin and noise can damage your hearing. Operators and
personnel working in close proximity must wear suitable eye, ear and body protection.
Fumes and gases can seriously harm your health. Use the equipment only in a suitably
ventilated area. If ventilation is inadequate, then appropriate fume extraction equipment
must be used.
Hot metal spatter can cause fire and burns. Appropriate clothing must be worn. Clothing
made from, or soiled with, combustible materials must NOT be worn.
Have a fire extinguisher nearby and know how to use it.
Magnetic fields from high currents can affect heart pacemakers or other electronically
controlled medical devices. It is imperative that all personnel likely to come into the
vicinity of any welding plant are warned of the possible risks before entering the area.
4. MAINTENANCE
All cables must be inspected regularly to ensure that no danger exists from worn or
damaged insulation or from unsound electrical connections. Special note should be made
of the cables close to the pistol, where maximum wear occurs. As well as producing
inconsistent welds, worn cables can overheat or spark, giving rise to the risk of fire.

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IMPORTANT SAFETY INFORMATION !
6
5. TRAINING
Use of the equipment must be limited to authorised personnel only who must be suitably
trained and must have read and understood this manual. This manual must be made
available to all operators at all times. Further copies of this manual may be purchased
from the manufacturer. Measures must be taken to prevent the use of this equipment by
unauthorised personnel.
6. LIMITATIONS OF USE
We recommend the use of movement aids such as a sack-cart or wheeled dolly when
moving the unit. The mass of the welding controller is 32kg and as such is suitable for
limited manhandling e.g. final positioning at the place of work. The controller is not
suitable for use in rain or snow or in an environment with increased risk of electric shock.
7. INSTALLATION
Ensure that the site chosen for the equipment is able to support the weight of the
equipment and that it will not fall or cause a danger in the course of its normal operation.
Do not hang connecting cables over sharp edges and do not install connecting cables near
heat sources or via traffic routes where people may trip over them or they may be damaged
by the passage of vehicles (forklifts etc).
8. INTERFERENCE
During welding operations, intense magnetic and electrical fields are unavoidably
produced which may interfere with other sensitive Electronic equipment.
All Taylor Studwelding equipment is designed, manufactured and tested to conform the
current appropriate European standards and directives regarding electromagnetic
emissions and immunity and as such is safe to use in any normal environment.
9. DISPOSAL
The equipment either wholly or any of its component parts may be disposed of as part of
general industrial waste or passed to a scrap merchant. None of the components used in
the manufacture are toxic, carcinogenic or harmful to health in their “as supplied”
condition.

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INTRODUCTION TO STUDWELDING
7
The Taylor Studwelding 800DA Drawn Arc controller when matched with an appropriate
pistol and earth cables is intended for precision stud welding up to 12 mm diameter
reduced base studs. The controller is easily transportable and has been designed to
operate with a minimum amount of maintenance.
The energy required to carry out the welding operation is derived from a fully micro-
processor controlled transformer-rectifier inside the controller.
Taylor Studwelding Systems Ltd pistols are modern, ergonomically designed and offer
maximum comfort in handling with minimum operator fatigue.
THE PROCESS
The process of drawn arc studwelding is long established and well proven. The basic steps
are as follows :
• A measured amount of weld stud protrusion is set at the welding pistol.
• Once in position, the pistol lifts the stud away from the work-piece, simultaneously
striking an arc between the two.
• Both the tip of the weld stud and the surface of the work-piece melt as the arc is
sustained for a pre-determined interval.
• At the completion of the pre-determined interval, the pistol returns the weld stud to
the molten pool on the work-piece, thus forming a weld.
The most common and traditional drawn arc welds have a weld duration greater than
100ms and employ the use of a single use ceramic arc shield, commonly referred to as a
ferrule. This ferrule helps to protect the arc during the weld and assists in formation of the
final fillet. Post welding the ferrule is removed and disposed of.
It is possible to stud weld without a ferrule. This method is more commonly employed with
welds having a duration of less than 100 ms and this type of weld is referred to as short
cycle stud welding. Although no ferrule is employed, it is recommended practice in short
cycle welding to employ a suitable shielding gas to reduce the amount of porosity in the
completed weld and improve weld quality.

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GUIDE TO EXTERNAL FEATURES
8
FRONT PANEL
1. CARRYING HANDLE
2. MAINS ON/OFF SWITCH
3. VENTILLATION HOLES ! DO NOT OBSTRUCT !
4. WELDING EARTH CONNECTION SOCKET
5. CONTROL PANEL SEE PAGE 9
6. SHIELDING GAS OUTLET SOCKET
7. PISTOL CONTROL CONNECTION SOCKET
8. PISTOL WELDING CONNECTION SOCKET
1
2
3
4
5
6
7
8

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GUIDE TO EXTERNAL FEATURES
9
CONTROL PANEL
1. WELDING TIME SETTING PUSHBUTTON
2. WELDING INDICATOR - GREEN
3. WELDING TIME/GAS PURGE TIME DISPLAY WINDOW
4. PISTOL TRIGGER ACTUATED INDICATOR - YELLOW
5. ADJUSTER KNOB
6. GAS PURGE TIME SETTING PUSHBUTTON
7. GAS FLOWING INDICATOR - GREEN
8. STUD TO WORKPIECE CONTACT INDICATOR - YELLOW
9. PISTOL LIFT COIL ENERGISED INDICATOR - YELLOW
10. SUPPLY FAULT INDICATOR - RED (INDICATES LOSS OF PHASE)
11. CONTROLLER OVER TEMPERATURE INDICATOR - RED
1 2 3 4 5
6 7 8 9 10 11

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GUIDE TO EXTERNAL FEATURES
10
BACK PANEL
1. RATING/SERIAL PLATE
2. SHIELDING GAS INLET
3. 3 Ph MAINS CABLE INLET GLAND
4. VENTILLATION GRILLE ! DO NOT OBSTRUCT !
1 3
2 4

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SETTING UP AND WELDING
11
Set up the control unit at the place of work, ensuring that the
mains switch is in the OFF position.
Plug the controller into a suitable three phase AC supply with a
32A motor rated fuse/breaker.
Plug the welding earth cables into the controller. Note that the
cable end weld plug has a peg which mates with the key slot in
the panel mounted socket.
IMPORTANT! Secure the connectors with a clockwise turn until
they lock. Failure to do this may result in damage to the
connectors during welding.
Attach the welding earth clamps to the work piece at
approximately 180° to each other; this will help prevent "arc-
blow" when welding takes place. Prior to fitting the clamps,
ensure that the contact area of the work piece is free from rust,
paint, grease etc., as this will result in a poor welding
connection.
Plug the welding pistol cable into the controller. Note that the
cable end weld plug has a peg which mates with the key slot in
the panel mounted socket.
IMPORTANT! Secure the connectors with a clockwise turn until
they lock. Failure to do this may result in damage to the
connectors during welding.
Plug the pistol control cable into the controller. Note that the
cable end plug and panel-mounting socket are keyed to prevent
incorrect fitting. Push the plug firmly home and twist the locking
ring to secure the plug in position.
Set up the welding pistol according to the instructions in the
operating guide supplied with the pistol.

V-21A
SETTING UP AND WELDING
12
Switch the controller ON by turning the mains switch
clockwise through 60°. The display will illuminate and
the ventilation fan will start.
A guide to the recommended time settings can be found
on page 14 of this guide.
The 800DA controller has a fixed 800A current output,
with only welding time being operator adjustable.
Referring back to the control panel guide on page 9, set
the controller by following these simple steps :-
SETTING WELD TIME
1. Press and hold the welding time setting
pushbutton (1).
2. Turn the adjuster knob (5) until the required time
is displayed in the time display window (3).
3. Release the pushbutton (1). The welding time is
now set.
SETTING THE GAS PURGE TIME
1. Press and hold the gas purge time setting
pushbutton (6).
2. Turn the adjuster knob (5) until the required time
is displayed in the time display window (3).
3. Release the pushbutton (6). The gas purge time is
now set.
4. If no gas purge is required, this time parameter
must be set to 0 (zero).

V-21A
SETTING UP AND WELDING
13
Place the pistol perpendicular to the work piece with
the stud touching down at the desired location to be
welded. Press down on the pistol until the ceramic
ferrule rests firmly on the work piece. Press the
trigger to initiate the weld sequence.
See the section on Studwelding Techniques for
further advice.
The welding process is as follows: -
1. Start.
2. Pistol lifts stud.
3. Pilot Arc strikes.
4. Main Arc strikes melting both stud and workpiece.
5. Arc stops. Pistol plunges stud into molten pool.
6. Weld complete.
Having welded the stud, draw the pistol vertically off
the stud. Failure to do this may cause the split tines
of the chuck to splay out. This will result in the chuck
and stud arcing together during subsequent welds.
Finally, remove the ferrule by lightly tapping until it shatters. Visually
inspect the weld.
For a guide to the inspection of the welded stud see the sections on
Inspecting and Testing Welded Studs.
1 2 3
4 5 6

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WELDING TIME AND CURRENT SETTINGS
14
This page is intended as a guide to setting your machine.
The setting charts were established with the performance of repetitive weld tests using the
800DA controller and our standard DA7-A pistol with SC studs manufactured to standard BS
EN ISO 13918 and mild steel grade CR4 and were performed using a shielding gas purge
(Argoshield Light) at 5l/min.
The settings are given only as a general guide and it is recommended that sample welds
be carried out on your own material, as quality of materials and site conditions may vary
from user to user.
STUD TIME (ms)
M3 5
M4 10
M5 15
M6 25
M8 65
M10 100

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VISUAL WELD INSPECTION
15
This page will help you to recognise a poor weld when you see one and give some of the
possible explanations as to how it may have occurred. Your test welds should look like the
first example diagram in the series and once you transfer to the actual job, periodic checks
should be made to ensure that your welding is consistently good.
POINTS TO LOOK FOR IRRESPECTIVE OF PROCESS USED.
• L.A.W. (Length After Welding). This should be correct to within + 0 / - 1 mm.
• The base fillet of the welded stud is complete.
• The welded stud is perpendicular to the work-piece.
WHEN USING A CERAMIC FERRULE.
This diagram is an example of a good normal weld, fulfilling the criteria above
i.e. The LAW is correct, the stud has a complete, well formed and even fillet
and is also perpendicular to the work-piece.
The following examples will help you to recognise the most common types of
poor weld, explain the possible causes of these problems and how to remedy
them.
EXAMPLE 1
PROBLEM : Insufficient heat, causing the L.A.W. to be too long and the
fillet to be underdeveloped and / or incomplete.
REMEDY : Increase the welding time (see page 12).
EXAMPLE 2
PROBLEM : Excessive heat, causing the L.A.W. to be too short and the
fillet to be too large and messy, spreading out under the
ferrule and / or splashing up the threads.
REMEDY : Reduce the welding time (see page 12).
EXAMPLE 3
PROBLEM : The ferrule is not being held firmly against the work-piece
and / or the stud is binding against the ferrule.
REMEDY : Hold the pistol firmly down to the work-piece (see page 13).
and reset the alignment of the stud and ferrule (refer to your
pistol setup guide).
EXAMPLE 4
PROBLEM : Insufficient stud protrusion set on the pistol.
REMEDY : Adjust stud protrusion to correct setting (refer to your pistol
setup guide).
EXAMPLE 5
PROBLEM : Poor alignment i.e. stud is not perpendicular to the work-
piece.
REMEDY : Hold the pistol perpendicular to the work-piece (see page 13).
NOTE : If the misalignment is only slight and in all other aspects the
weld is good, then the weld may be salvaged by tapping
straight with a soft mallet.
✓






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WELD TESTING
16
There are two factors which should receive special attention in establishing visually
whether or not a stud weld is sound. These are :
• The length after weld (L.A.W.) of the stud should be correct. That is to say that a stud
which is intended to be 50 mm long after welding, should be correct within +0/-1
mm. A word of explanation is perhaps needed on this point. All studs produced
include a "weld allowance". This allowance is so arranged for the different diameters
of stud, that it will be completely melted during the welding process, provided of
course that the correct conditions have been established and the correct values of
current and time are used.
• The fillet of metal formed around the base of the stud should be well formed,
reasonably evenly distributed, completely free from blow holes and of a silver blue
colour.
These two factors combined form the basis of all visual stud weld examination. It should
be the aim of every operator to produce these results.
Under normal conditions a stud welded to clean mild steel plate of adequate thickness
having the correct L.A.W. and fillet formation. as described above, will be a satisfactory
weld.
It should be remembered, however, that different applications or conditions will produce
slightly different visual results, particularly in the appearance of the fillet, i.e.. Slightly
rusty, dirty or oily plate will produce blow holes in the fillet, in proportion to the degree of
plate contamination.
Welding close to some magnetic obstruction may produce uneven fillet distribution. Too
much power will produce a fillet that flows too easily and is lost either up in the threads of
the stud or out through the ferrule vents, while too little power may not melt sufficient
material to form a complete fillet.
It is important, therefore, to judge the degree to which these possible variations will affect
the weld strength, but in general, provided that the L.A.W. is correct and the fillet
formation is not unsightly, a visual examination is all that is required.
Further testing may be carried out on a "percentage of production" basis, and the methods
used fall into the classes outlined below.
1. DESTRUCTIVE TESTING.
Should only be used on studs welded to samples and test pieces.
• Hammering a stud over may look spectacular, but it is not a satisfactory test, as the
direction and force behind the blows is uncontrolled, as also is the point at which the
impact takes place. The length, diameter and type of stud also have an effect on the
results obtained.
• Bending the stud over by using a tube of approximately the same bore as the stud
diameter. This method is preferred to hammering, but again no conclusive evidence
as to the strength of the weld is obtained.
• Loading the stud by the use of washers / spacer and a nut until the stud breaks. This
method is much more conclusive and should show that the weld is in fact stronger
than the stud. Use of a suitably calibrated torque wrench for this test will give an
indication of the U.T.S. developed by the stud material under test.

V-21A
WELD TESTING
17
2. NON DESTRUCTIVE TESTING.
Generally the most practical way of testing threaded stud welds, without destroying the
stud, is with the use of proof tests. A torque wrench is particularly useful for this purpose.
Below and overleaf are some tables which you may find useful. However, it must be noted
that :
• Formulas & data shown are intended for guidance only.
• In applications where control of preload is important, the torque - tension
relationship should be determined experimentally on the actual parts involved
including any lubricants.
• The coefficient of friction (k) varies with material, surface finish and lubricity of
threads and bearing areas of fastened parts.
• For standard steel screws it is 0.19 to 0.25 and 0.13 to 0.17 for plated screws. Anti-
seize materials and lubricants can lower k to 0.05. For some stainless steel threads
and parts not coated or lubricated k may be as high as 0.33
• All the figures are approximate and do not form part of any specification.
• Designers and specifiers must satisfy themselves that the studs and materials
chosen are suitable for their particular application.
All torque figures are calculated by the formula : T = kDP
Where : T = Torque (Nm)
D = Effective Stud Diameter (m)
k = Coefficient of Friction (0.2 used for calculations)
Material properties: (N/mm²) (N/mm²) (N/mm²)
UTS Yield Safe
Mild Steel (4.8) 420 340 272
Stainless Steel (1.4301) 540 350 280
Note: safe loads are 80% of the yield

V-21A
Stud loads - Full Base Drawn Arc Studs (kN)
Torque required to reach the loads above (Nm)
Stud loads - Reduced Base drawn Arc Studs (kN)
Torque required to reach the loads above (Nm)
Mild Steel Mild Steel Mild Steel Stainless
Steel
Stainless
Steel
Stainless
Steel
Thread UTS Yield Safe UTS Yield Safe
M5 x 0.8 5.8 4.7 3.7 7.4 4.8 3.8
M6 x 1.0 8.2 6.6 5.3 10.6 6.8 5.4
M8 x 1.25 15.2 12.3 9.8 19.6 12.7 10.1
M10 x 1.5 23.8 19.2 15.4 30.6 19.8 15.8
M12 x 1.75 34.6 28.0 22.4 44.5 28.8 23.1
M16 x 2.0 64.6 52.3 41.8 83.1 53.8 43.1
Mild Steel Mild Steel Mild Steel Stainless
Steel
Stainless
Steel
Stainless
Steel
Thread UTS Yield Safe UTS Yield Safe
M5 x 0.8 4.9 4.0 3.2 6.3 4.1 3.3
M6 x 1.0 8.2 6.7 5.3 10.6 6.9 5.5
M8 x 1.25 20.7 16.8 13.4 26.7 17.3 13.8
M10 x 1.5 40.5 32.8 26.2 52.1 33.8 27.0
M12 x 1.75 71.0 57.5 46.0 91.3 59.2 47.4
M16 x 2.0 181.0 146.5 117.2 232.8 150.9 120.7
WELD TESTING
18
Mild Steel Mild Steel Mild Steel Stainless
Steel
Stainless
Steel
Stainless
Steel
Thread UTS Yield Safe UTS Yield Safe
M6 x 1.0 7.2 5.8 4.7 9.3 6.0 4.8
M8 x 1.25 12.6 10.2 8.2 16.3 10.5 8.4
M10 x 1.5 20.5 16.6 13.3 26.4 17.1 13.7
M12 x 1.75 29.7 24.0 19.2 38.2 24.8 19.8
M16 x 2.0 57.4 46.5 37.2 73.8 47.8 38.3
Mild Steel Mild Steel Mild Steel Stainless
Steel
Stainless
Steel
Stainless
Steel
Thread UTS Yield Safe UTS Yield Safe
M6 x 1.0 6.8 5.5 4.4 8.8 5.7 4.6
M8 x 1.25 15.7 12.7 10.2 20.2 13.1 10.5
M10 x 1.5 32.5 26.3 21.1 41.8 27.1 21.7
M12 x 1.75 56.6 45.8 36.6 72.7 47.1 37.7
M16 x 2.0 151.7 122.8 98.3 195.1 126.4 101.2

V-21A
STUDWELDING TECHNIQUES
19
The operating instructions given previously in this guide apply to the majority of general
applications where it is possible to use the pistol in the down hand position and with
standard cable lengths. For many applications these conditions do not apply and the
following notes will give some guidance as to the methods used to obtain satisfactory
results for a variety of applications.
1. WELDING TO A PLATE IN THE HORIZONTAL POSITION.
In this position there is a tendency for the weld metal to run to the underside of the stud
during welding, due to the action of gravity, resulting in an uneven fillet. The effect is
more noticeable as stud diameter increases and generally speaking it is not recommended
that studs of 12 mm diameter and over be welded to vertical plates for this reason. The
essential requirement to obtain satisfactory fillet formation is to use the shortest weld time
possible with increased welding current. Welding to a vertical surface reduces the
maximum size of the stud a given power source will weld.
It must be remembered, that greater care is required to ensure that the stud is
perpendicular to the work piece. A special tripod foot attachment can be supplied if
required. Take particular care to keep the ferrule grip, foot adapter and chuck clean.
2. WELDING TO A PLATE IN THE OVERHEAD POSITION.
IMPORTANT ! You must protect your face and shoulders with a helmet and cape before
carrying out overhead welding operations. Weld spatter can do a lot of damage !
Firstly, obtain satisfactory weld settings in the down hand position before making attempts
in the overhead position. Since the weld metal is transferred from stud to plate in small
particles in the down hand position, it follows that, when welding overhead, the transfer
takes place against gravity. As with vertical welding the best results will be achieved using
the shortest possible weld time with increased welding current.
It is important that the ferrule grip, foot adapter and chuck are kept free from spatter build
up as this can cause stud return problems or possibly short out/bridge out the weld.
3. PISTOL ADJUSTMENTS WHEN WELDING IN THE VERTICAL OR OVERHEAD POSITIONS.
Problems may be encountered when welding in the vertical or overhead positions with a
damped pistol. To prevent problems occurring, where it is possible to do so, the damping
effect should be removed or turned off.
Welding can then continue as outlined in sections 1. and 2.
4. USING LONG CABLE LENGTHS.
Frequently the pistol must be used some distance from the nearest available mains
supply, for instance on board ship, in power stations and building construction, in
workshops building large pre-fabricated structures etc. In these cases long lengths of
welding cable are used and it must be realised at the outset that, the longer the cables the
smaller the maximum diameter of stud which can be welded with a given power source.
To help get over this problem, if larger diameter studs are to be welded with long lengths
of cable, increase the welding cable conductor size.
Try to avoid running the pistol cables and the earth cables alongside each other as this can
cause a choking effect, reducing power. Also avoid coiling any excess cable as this will
have the same effect.

V-21A
STUDWELDING TECHNIQUES
20
5. WELDING STUDS LESS THAN 25 mm LONG USING FERRULES.
As we have seen previously, the stud is held in a recess in the chuck and must be long
enough to allow us to set the correct protrusion. A standard chuck has a recess 12 mm
deep and ferrules vary in length up to 13.5 mm high. Thus if a stud is much less than 25
mm LAW we shall not be able to obtain the correct protrusion, i.e.. The chuck may hit the
ferrule on the return stroke and prevent the stud returning to the plate correctly.
This problem may be overcome by using "shallow recess" chucks (the recess depth is only
6 mm) or if the studs are required to be very short, by using a special type of stud known
as a "break-off" type. These studs have an overall LAW of 30 mm and are welded using a
standard chuck and ferrule. The stud is "grooved" at the required length from the welding
end. After welding, the surplus portion of the stud is broken off with a pair of pliers. By
these means, very short studs can easily be welded.
6. USING TEMPLATES TO ENSURE POSITIONAL ACCURACY.
When welding studs around the periphery of a flange, i.e. for cover plates, inspection
doors etc., positioning of the studs in relation to each other becomes most important. A
simple template made from 2 mm sheet, shaped to suit the component and provided with
clamps is usually the answer to this problem. The position of the studs is accurately
marked and holes drilled in these positions to accept either the ferrule of the stud to be
welded or, if using short cycle, the pistol gas shroud. The size of the holes should be the
outside diameter of the ferrule / shroud +0.4 mm. It is also advisable to provide 2 mm
thick pads underneath the template so that there is a space between the component and
template, this space will allow the gases developed during welding to vent properly from
the ferrule / shroud. For any further advice or help in the design of jigging or templates
contact your local field sales engineer.
7. MINIMUM PLATE THICKNESSES WHEN STUD WELDING.
When using standard Drawn Arc with ceramic ferrules, the minimum ratio of stud diameter
to plate thickness is 4 : 1 for plate thickness greater than 3 mm and 3 : 1 for plate
thickness between 1.5 mm and 3 mm. When using the short cycle system with or without
gas purging it is possible to weld equivalent size studs onto slightly thinner sections, due
to the short weld duration. These ratios ensure that the strength of the plate is sufficient to
support a stud of a given size when it is loaded, without there being a tendency for the
plate to distort.
Occasionally, however, it may be necessary to weld a stud outside of these ratios. This
can sometimes be accomplished without distortion by "heat sinking" the component, by
using a flat copper or water cooled backing piece behind the weld area, to support the
plate and assist in dissipating heat quickly.
8. WELDING STAINLESS STEEL.
Austenitic stainless steel studs of the 18/8 g/N : weld decay proof type can be supplied for
welding to similar parent material or mild steel. The technique does not differ from that
used for mild steel stud welding. There is a tendency with larger diameters of stainless
steel studs for metal transfer across the arc to take the form of large particles. If short
circuits occur then the arc can be heard to splutter. This may occur with any diameter of
stainless steel stud if the lift of the hand tool is not correct. Due to this tendency to transfer
in large particles increased lift may be required and time settings should be kept as low as
possible.