TINNIT Electroless Tin Plating Solution Tutorial

    This stuff can be bought on the web, at places such as http://www.web-tronics.com

    Using it is somewhat straightforward but the directions are geared toward someone who happens to have some lab equipment at hand, or at least quality kitchen supplies... It calls for heating the solution to a specific temperature in a pyrex dish.  Well some of us are college students and have no pyrex or thermometers, so we have to make do in a different way.  Also, they don't tell you what to expect.  When I first poured hot water into the salts, it expanded and formed a thick, grainy foam... It took some experimentation to see what I was doing wrong.

    To do it properly, you need enough heat.  Hot tap water turned out to be insufficient.  Take a glass jar (like a spaghetti sauce jar, etc.) and pour the salt packets into it.  Heat some water up in the microwave until it is reasonably hot, and pour 1 pint into the jar.  Fill a small saucepan with water, and place it on the stove, on medium heat.  Then just set the jar in the pan.  (ie - a double boiler) and stir the solution until the salt dissolves and you get a somewhat cloudy, yellowish solution, with no floating sediment (a few chunks at the bottom is somewhat unavoidable...)

    Then take the PCB's you wish to plate and put them in a small plastic container (small sandwich containers like you find at grocery stores are great) and pour in enough solution to cover them.  Agitate every couple minutes by rocking the container slightly.  After a few minutes you'll see some sediment forming in the solution.  After a while you should take the boards out of the solution, place them aside (I set them on the container's lid) and pour the solution back into the double boiler jar for a minute, stirring it, to re-dissolve everything.  Then just put the boards back in the container, pour some solution in again, and continue.

    Continue as long as you wish, until your board reaches the desired level of tin plating.  Even after 20 seconds the board will have a noticeable tin plating, but the label states it takes 10 to 30 minutes to achieve a bright tin plating.  I have not tried going that long, but feel free to experiment for yourself.

And here are the obligatory example shots... Note that it's a bit hard to get a decent shot of these boards in the lighting conditions I have here, but you can use your imagination.  The tin plating came out good but isn't extremely shiny, probably due to not being left in the solution for half an hour.