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Subject: Re: [Homebrew_PCBs] Re: Tin eletroplating

From: Adam Seychell <adam_seychell@...>
Date: 2003-11-15

Stefan Trethan wrote:
> well then,
>
> i just checked my chemical supplier has tin sulfate in his stock list.
> also sulphuric acid would be no problem at all.
>
> BUT i have not the slightest idea where to get the additives.
>
> I read this stuff always concentrates at the point of highest potential,
> preventing plating at this particular point, So you get a even coat
> as the additives move around all the time.
>
> just BAD that it isn't something simple.

That's basically the mechanism behind plating additives. But
there is a lot of things going on and all plating additives
consists of a number of compounds, each specifically doing a
job, and some are working together. The fact is
electrochemists don't really know exactly how additives
work. Developing a new plating additive its an art, not a
science.

As I said, you buy additives from electroplating suppliers.
If you cannot find any electroplating suppliers who sell the
correct acid tin sulfate plating additive, then find a
business who electroplates tin and ask them who their
supplier is for the additive they use.

Did you get pricing for the stannous sulfate ? When I was
quoted AUD$500 for a 25 kg bag, I looked at other options. A
bit of research and a $5 plant pot solved my problem.