Not to worry, this electroless tin solution works by a redox reaction with the copper and does not deposit any tin on the epoxy. I used it for years and never had any surface leakage issues. As with any material its important to wash the board completely to make sure you remove any ionic salts from any microscopic pores and fishers on the material surface.
Craig
--- In Homebrew_PCBs@yahoogroups.com, Alessio Sangalli <alesan@...> wrote:
>
> Hi, I was about to place an order for the precision scale and the
> chemicals needed for tinning but:
>
> - I use the H2O2 + HCl method for etching
>
> What was not clear from the thread that was going on several weeks ago,
> is if it can be used after etching the PCB and if it delivers a good
> result. Somebody reported it may create a layer of high impedence on the
> board; as my applications can be low-power electronics to SMPSs, I do
> not really like to deal with such "problem".
>
> The tinning method I am referring to is the one explained here:
> http://www.voodooengineering.com/index.php/pcbprocess/tinning
>
> And I was going to order the chemicals from:
> http://shop.ebay.com/quartzpegmatite/m.html?_nkw=&_armrs=1&_from=&_ipg=&_trksid=p4340
> as suggested by bebx2000
> Thiourea 98% Lab Chemical One Pound --> $11.99
> Stannous Chloride Anhydrous 98% 1/4 lb --> $8.99
> Sulfamic Acid 99.8% Lab Chemical One Pound. --> $5.99
>
> What to do? I'm quite confused.
>
> bye
> as
>