TINNING BOARDS - WICH PRODUCTS?

[tokyomatik]

Hi guys
i'm planning to etch some boards at home, and i would like also to use use a tinning product, to make the soldering process easier.
usually i buy everything from banzai or conrad, that is not far from my place(i'm in berlin).
but i'm not able to find anything on the respective catalogues.
could somebody please indicate me a particular brand, so i can try to ask for that, or, if it's not too much stress, anybody in germany could send me a package? i would pay also for the shipping costs

peace

[mph]

If you are looking for a very cheap but neat solution you could try to get some used silver bromide from a photograph shop.
Usually this product is used once to develop photos, then it is thrown away because there is not enough silver in the product to make lots of pictures with a good quality.
But for us DIYers it's wonderful, and photographs are often pleased to find a good solution to take this chemical away from their shop.

I've tried this once, and cost was zero euro; I've simply let my pcb in a bath with this AgBr for few hours and that was done!
Plus silver is an excellent conductor for electronics.

Anyway there are commercial stuff like the Etamag from the KF brand and some other workalike.

[tokyomatik]

i thought the silver bromide was used as emulsion to make the photopaper or films and not the solution to develope them...???

http://en.wikipedia.org/wiki/Silver_bromide

are u sure i have to ask for that??


check this

http://en.wikipedia.org/wiki/Photographic_developer

[mph]

er, well maybe I've messed with the silver nitrate as the stuff I used was soluble in water... I have a doubt as I did this some years ago but what I get was a used liquid which has been involved in the developpement process.
Maybe the best would be to have a talk with your local photograph shop and see what liquid chemical you could use to put some silver on the copper tracks of you pcbs, he'll surely know what is it exactly.

Sorry for the lack of precision.

[brock]

I wouldn't plate them. If you're assembling boards soon after etching them the the copper will be very easy to solder to. I found the immersion tin solutions oxidize faster than bare copper and are much harder to prepare for soldering if you store them for a few months, whereas bare copper takes a few seconds of scrubbing with steel wool or an abrasive cleanser and you're good to go. Even after twenty years it doesn't take much to make a bare copper board solderable. Silver nitrate is not worth the hassle. Aside from the fact that your skin will turn black if you touch it, your boards will oxidize anywhere you touch them. I had no success with this. If you're partially assembling a board, or leaving some pads unconnected but will want to solder them later you can easily solder plate them by loading up some solder wick with solder and lightly dragging it over the pads you want to plate. Instant plating and you'll be able to solder with no preparation years later.

[ericcoleridge]

This has been my experience too. The tinned traces oxidize very badly, very quickly.

But I still want silver traces sometimes. I wonder if there isn't some kind of spray preservative that could be applied after tinning to maintain the bright silver finish?

[marvkaye]

[Clack]

I use this

http://www.rapidonline.com/Tools-Equipment/Kontakt-chemie-Flux-Sk10-Spray-200ml-87-0715

Its a flux spray so it protects from oxidization if I spray it just after etching and also helps soldering - much better than messing it up with acrylic spray.

I also had no luck with tinning solution, it oxidised really fast and I also tried exhausted fixer from a photo lab which didn't stick.

Thing is that the exhausted fixer is actually quite valuable as there is an industry of reclaiming the silver from the fixative so the lab was quite reluctant to give me some.