I got my chemicals back in 1972 from my college chemistry department to do the boards for my 8 digit frequency counter senior project. I did a lot of borads back in those days but not much in the past 20 years untill recently. Recently a did a few small boards and I still had the plating chemicals from 1972 which still worked fine. The Stannous Chloride looked a little funky but still gave good results.
I have seen all the chemicals on E-bay but the Stannous Chloride seems to be a little harder to find.
As for measurements the article provided a much more accurate formula indicated below. (LOL)
Stannous Chloride 1/4 teaspoon
Thiourea 1/2 teaspoon
Sulfamic Acid 1/2 teaspoon
Water 1/3 Cup
I didn't have a scale so I used the teaspoon method and then only to a very crude approximate. I found it was not all that critical.
The formula also called for an optional brightener but I never found that it did anything and I stoped using it after I ran out. The brightner was 5mg of Alizarin or Alizarin red S. The stuff must have been expensive because the chem department would only give me a very small amount. It didn't seem to disolve and just floated on the top of the solution.
It woked quite well and really helped out with the soldering, not tried it with any SMT and solder paste though.
For etching, early on I used ferric chloride but switched to ammonium persulfate because of the mess caused by ferric chloride. No toner transfer in those days -- used Shipley AZ111 pos photo resist and halide film masters from hand taped 2:1 artwork.
Craig
--- In Homebrew_PCBs@yahoogroups.com, Alessio Sangalli <alesan@...> wrote:
>
> On 07/21/2010 09:29 AM, designer_craig wrote:
> > I have very good luck with elctroless tin. The formula I use came
> > from the September 1971 issue of Ham Radio magazine.
> >
> > .5g Stannous Chloride 2.0g Thiourea 3.0g Sulfamic Acid 100.0 mL
> > Distilled water
>
> Where do you get the chemicals? Also, do you have a very precise scale?
> My kitchen scale can theoretically meausure with the precision of one
> gram but how can I trust it for such small quantities?
>
> Do you have pictures of the process?
>
> bye
> as
>