Homebrew PCBs

JanRwl@... wrote:
>  
> In a message dated 3/29/2006 2:24:48 A.M. Central Standard Time,  
> stefan_trethan@... writes:
> 
> I'm not  sure the tinnit and other electroless stuff would make a thick   
> enough plating to work as resist.
> 
> 
> 
> Correct.
> 

It has not to do with tin plating thickness, but chemical reactivity. 
Tin will react with all acidic copper etchers that I know of. That is 
why anyone who wants to etch a PCB using tin as a metal etch resists 
must use an alkaline based copper etchant. The higher the pH the more 
stable tin metal becomes. A common alkaline etchant is the ammonia 
chloride types used by most of the PCB fabricators in the world.