Sulfamic Acid (H3NS03) is correct for this formula. I have also seen formulas that use Sulfuric acid and suspect they work in a similar way. The Sulfamic acid is a white powder so none of the chemicals in the formula are liquid.
Wikipedia: "When compared to most of the common strong mineral acids, Sulfamic acid has desirable water descaling properties, low volatility, low toxicity and is a water soluble solid forming soluble calcium and iron-III salts. Its also finds applications in the industrial cleaning of dairy and brew-house equipment. -- "The deprotonated form (sulfamate) is a common counterion for Nickel(II) in
electroplating."
Craig
--- In Homebrew_PCBs@yahoogroups.com, "fredbutz" <fredbutz@...> wrote:
>
> You sure it isn't Sulfuric Acid?
> I saw another formula, same chemicals, but used Sulfuric Acid instead of Sulfamic Acid. I just want to try the Ham Radio Magazine formula.
>
> --- In Homebrew_PCBs@yahoogroups.com, "designer_craig" <cs6061@> 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
> >
> > The solution is ued cold, I never tired heating it. It plates up in a few minutes and does a goog job but can't be use as a resist for further etching. The solution does not keep and I always make up a fresh batch for each board making session. I would usually mix up less than 100 mL depending on the size and number of boards I was doing.
> >
> > Craig
> >
> > --- In Homebrew_PCBs@yahoogroups.com, Alessio Sangalli <alesan@> wrote:
> > >
> > > Hi, as I am perfectioning my PCB making, I reached a point where I can
> > > do very good boards, but especially if I am making a bigger, double-face
> > > one, with huge ground planes, tinning takes simply too much time, and if
> > > I want to do it properly, I end up wasting a lot of solder wick braid to
> > > remove the excess tin.
> > >
> > > I've read past messages but I was not able to find a method that is well
> > > documented and can be considered a viable solution for a hobbyst that
> > > makes only few boards per month.
> > >
> > > bye
> > > as
> > >
> >
>