pcb tinning

[Joe Viau]

I'm assuming that you got 17 ounces for $30.  A 4.2 ounce bottle will run you around $9.  This is the one that I got, I want to see how well it works before commiting to more.

Check here for distributors:

http://www.mgchemicals.com/distributors/index.html

[object88]

Is tinning done before or after drilling?  I'm guessing before, as I would imagine that if you tin after you drill, you may tin into the drilled holes, making component placement a pita.

Regarding "Liquid Tin", you're coating the entire board, so I assume that the Liquid Tin isn't conductive itself, and that it's just a sort of varnish for PCBs?  And how does that interact with the soldering of components-- how does the solder make good contact with the traces if they're covered?  Or do I have the wrong idea entirely?

Sorry for all the questions, but I really, really like the look of a well-treated PCB.

Thanks!

[Fret Wire]

I tin after I drill the boards. That way there is no exposed copper left. It's the last thing I do to a board, after cutting, smoothing and drilling. All the rough handling is done before I tin.  You can do it either way, no harm.

Liquid Tin is basically the consistancy of water, and only plates exposed copper. It is conductive, does not fill any drilled holes, and does not coat the rest of the board. Once you lift the board out of the solution, it rinses right off with warm water. Only the copper traces are plated. Just make sure the traces are clean and degreased first. A little tip: it does not apply a thick plating, like a heavy chrome plate...don't try to buff it with steel wool or anything similar to make it shine. You'll see copper again.

BTW, I went and sprang for the 17oz bottle, seems to last forever. It does seem expensive intitially, but when you consider how easy it is to use, the fact that it has no fumes, can be used inside in any weather, and how well it works, it is pretty damn good for the price.

[object88]

Thanks!  Much appreciated!