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Think & Tinker, Ltd.
P.O. Box 1606, Palmer Lake, CO 80133
Tel: (719) 488-9640, Fax: (866) 453-8473
Sales: Sales@thinktink.com, Support: Support@thinktink.com
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Think
&
Tinker
Ltd.
SkypeMe at
"thinkntink"
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| Rolling Your Own Etchant |
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Before handling and/or using any toxic and/or highly corrosive material, you must familiarize yourself with its safe handling procedures and analysis techniques.
Peroxy-sulfuric etchants are made to run in a temperature range from 110° (immersion
baths) to 120° (air agitated and spray systems). The lower temperature is recommended for
immersion baths that do not employ some means to remove the heat that is generated during
copper etching. Excessive heat build up in such a system can lead
to a catastrophic exothermic reaction that can damage, or destroy, your etching tank and
sparger (not to mention your PCB shop). Air agitation or spraying of the
etchant during operation removes a significant amount of heat from the bath, requiring a
higher initial operating temperature.
As you use the recipes below, be advised that many vendors only carry 35% (or 50%)
hydrogen peroxide in 55 gallon drums and you may have to pay as much as $100 in HAZMAT
charges to have it delivered.
| Bulk Etchant Recipes |
| Mix components in the order presented! |
| Type |
Component |
Concentration by volume |
I
m
m
e
r
s
i
o
n
|
deionized (or distilled) water |
41% |
| 35% sulfuric acid (car battery acid) |
29% |
| Electrochemical, Inc. FT-2 Catalyst (stabilizer) |
10% |
| Concentrated copper sulfate (35 oz.CuSO4/gal)* |
10% |
| 50% (wt.) hydrogen peroxide** |
10% |
| Generally speaking this bath also works well for bubble assisted etchers,
"wave etchers", and some models which employ mechanical agitation of the
workpiece. |
| * The addition of copper sulfate to the bath is not strictly necessary
since it will form as the primary byproduct of etching copper. Be advised, however, that
the performance of the bath will be less predictable until the copper sulfate content
approaches 6 oz./gal (48 grams/liter) by analysis
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| ** If 50% hydrogen peroxide is not available, a 35% (wt.) or 19% (wt.)
solution can be used. Remember to scale the amount added based on the concentration used
(see hydrogen peroxide analysis).
|
| Type |
Component |
Concentration by volume |
S
p
r
a
y
|
deionized (or distilled) water |
40% |
| 35% sulfuric acid (car battery acid) |
35% |
| MFG 244 Stabilizer |
5% |
| Concentrated copper sulfate (35 oz.CuSO4/gal)* |
10% |
| 50% (wt.) hydrogen peroxide** |
10% |
| * The addition of copper sulfate to the bath is not strictly necessary
since it will form as the primary byproduct of etching copper. Be advised, however, that
the performance of the bath will be less predictable until the copper sulfate content
approaches 6 oz./gal (48 grams/liter) by analysis
|
| ** If 50% hydrogen peroxide is not available, a 35% (wt.) or 19% (wt.)
solution can be used. Remember to scale the amount added based on the concentration used
(see hydrogen peroxide analysis).
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Established 1990
On the web since 1994
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Sales: 1-(719) 488-9640 Tech Support: 1-(719) 488-9640 Fax: 1-(866) 453-8473
Copyright © 1994 - 2014 Think & Tinker, Ltd.
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