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Subject: Re: [Homebrew_PCBs] Tin salts

From: mpdickens <md30022@...>
Date: 2003-11-13

Wouldn't this
> allow for less
> dangerous chemicals
> than electroless plating?

Your kidding, right?

The Metal Finishing Guidebook lists three formulations
for immersion deposits of tin onto copper, only one
formula is free of really nasty stuff. Here is that
formula:


Stannous chloride 3.8 g/L
Thiourea 49.5 g/L
Sulfuric acid 12 ml/L

Combine the compounds at a temperature of 80-120
degrees Fahrenheit.


The TINNIT crystals are more than likey a solid
formulation of the above because this is the only
formula that is not deadly poisionous. Electroplating
ANYTHING. produces nasty stuff that has to be disposed
of.

If I were going to plate tin onto a pcb, I'd use the
TINNIT crystals: They are premixed, cheap and not as
hard on the environment as the by-products produced by
electroplating.


Best regards


Marvin Dickens
Alpharetta, Georgia USA

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