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Etchants
Ferric-III-chloride is very easy to handle, has very good etching quality and broad band of applica-
tion. That is why it is the most popular etching agent for laboratory uses. Ferric-III-chloride has a
high etching speed and ensures perpendicular copper walls after etching. We strongly recommend
to use ferric-III-chloride with our machines.
Mix 800 g Granulate per litre water. This will be 1.4 l of ready solution. Ferric-III-chloride etches
warm and cold. The optimum temperature is approx. 45°C.
With our etching machine JET 34 a fresh solution of ferric-III-chloride etches 35 µm Cu in approx.
70 seconds. With increasing saturation etching time goes up to 3 Min for 35 µm Cu. Under-etching
increases only slightly.
Ferric-III-chloride can take up to 50 g Cu per Litre. In reality you will not reach that limit, because
etching time will take too long. Recognize the saturated solution from its milky look.
Experienced users add small portions of 15% Hydrochloride acid (HCl) to the used solution to pre -
vent copper mud and Ferric stain in the machine. We will supply further information on request.
The used etching agent has to be disposed according to your national legislation.
We do not recommend to neutralize the used etchant, because you have to precisely analyse the
copper concentration after neutralisation. In Germany copper concentration in waste water has to be
less than 0.5 mg Cu/l.
Your Disposal administration will advice you on how to dispose the used etchant. Additional informa -
tion you will find in the material safety data sheet (M D ).
By the way: the brown spots on clothing and items caused by Ferric-III Chloride are easily removed
by our stain remover RX3.
Other Etchants:
Etchants Pros Cons
Ferric-III-Chloride Cheap, high copper capacity (50g/l)
good etching rate (0,5µm/s), stable,
good sharpness, low underetching, not
considered as a dangerous good, stains
easily removable with RX3
sludge formation
Regeneration only difficult
ammonium persulfate „clean“, good etching rate (8-30µm/min)
and copper capacity (30-40 g/l)
Forms complex salts (including double salts of
copper sulphate and ammonium sulphate), dis-
posal 10 times as expensive as Fe3Cl, corrosive
fumes, Crystalline deposits at temperatures be-
low 30 ° C, which are sharp as glass and can
damage pumps and cut moveable machine
parts,
odium persulfate no sludge, suitable for metal, copper
can be deposited electrolytically
Low etch rate (0.1-0.2 micron/s), does not etch in
cold state, decomposes when heated (especially
in the vicinity of the heating rod), catalyst (mer-
cury) is toxic.
copper chloride Regenerable, good capacity (100g / l)
and etching rate (30μm/min)
Bath control is very complicated, fumes are
toxic/aggressive
ammonia suitable for metal resist, good copper
capacity (up to 200g / l)
bath control difficult, exothermic reactions, toxic
fumes, complex salts, crystallization risk
