pcb tinning

[wef200]

Im looking for some alternatives for pcb tinning. I have heard of a product called Tinnit from datak. Does this work well? Where can I get it?

Other than this product I need to somehow protect the copper from corrosion on a board that I already made and soldered. Is there anyway I can coat this board after components are placed and soldered? Im not sure if I can use the Tinnit product after board has been assembled. Are there any cheaper ways to protect board other than Tinnit?

Thanks

[Paul Marossy]

I have heard people say good things about Tinnit. I have no personal experience with the stuff, though. You could cover the finished PCB with lacquer or a product similar to GC Electronics "Insulating Coating".
Here is a picture of what a bottle of that looks like:

[Mike Burgundy]

tinnit and the likes are apparently VERY toxic and environment-unfriendly. This is the reason it's unavailable over here.
I like to tin/protect boards, though - if you cover the board in whatchummacallit - solution? s39? The stuff that cleans the copper before soldering - it's in electronics solder core as well. It's available separately, and if you smear a little on the pcb, and use a pre-tinned wide chiselhead soldertip (hot!) to wipe the board with, you should get comparable results. It's kind of a knack.
Lately I've taken to leaving the developed bits of etch-resist on, and only carefully polishing the pads clean, which seems to work. A dremel with flex extension and one of those tiny rubbery polishing bits is essential for this.

[R.G.]

A lot of commercial single sided stuff is roller tinned. That is, a metal roller spins in a pool of molten solder and the PCB is passed over the roller, copper side down after an application of liquid flux.

That's a little complicated for home use, but I came up with a similar method. I got a 1" brass pipe 6" long at the hardware store. I drilled a hole into it in the center, and threaded the hole for 1/4"-20. I threaded a 1/4"-20 threaded rod into the hole and jammed it in place with a nut. Then I added an insulating handle to the 1/4"-20 threaded rod.

I sanded the  opposide side of the brass pipe smooth, coated it with flux, then heated it with a propane torch flame inside the pipe until the pipe could be tinned with solder.

To tin a board, you affix the board to a heatproof surface, brush on liquid flux, then heat the brass pipe with a propane torch until you can load the tinned side up with solder. Once the solder flows, swipe the solder-ey side across the fluxxed copper - bango, swipe-tinned board.

[Mike Burgundy]

You mentioned that one before and I forgot - good one.
And thank you, flux, is the word. Couldn't remember that for the life of me

[gez]

Lately I've taken to leaving the developed bits of etch-resist on, and only carefully polishing the pads clean, which seems to work. A dremel with flex extension and one of those tiny rubbery polishing bits is essential for this.

That's a good idea Mike.  I think I might try using an earbud dipped in nail polish remover to do this though, it would remove the resist on the pads without the need to mess about with drills (or so I should think - apologies if you've tried this and it doesn't work well).

[Mike Burgundy]

I haven't and I will!

[Aharon]

There's a spray for that and it's sold at electronics shops,give it a coat and off you go.
Aharon

[Jason Stout]

I use steel wool to remove the resist, and never tin. I don't feel that tinning protects the circuit from any real damage, but it may ease the construction a bit.

[wef200]

Thank you all for the good advice, I was wondering if a spray lacquer would work originally, now Im going to try it..

Thanks All!

[Joe Viau]

Out of curiosity, did the spray laquer work?

TIA,
Joe

[sir_modulus]

A cheap and very good product for tinning is: MG Chemicals "Liquid Tin".

Cheers,

Nish

[Mike Burgundy]

I haven't used spray laquer yet on a pcb, but the acetone (nail polishremover) works great. I just leave all the parts I don't need to solder on uncleaned, and the copper keeps on shining under the photoresist.
This is just my way of doing things. I think I can agree with people saying it doesn't matter much, but I like it anyway - hey,at least it looks better after a couple of years  

[Fret Wire]

A cheap and very good product for tinning is: MG Chemicals "Liquid Tin".
Cheers,
Nish

Last year I switched to that and will never go back to Tinnit. Tinnit does work good, but you have to heat it, and the fumes aren't healthy. MG's Liquid Tin works great, pour it into a plastic pan, drop in the pcb, and 3-5 mins later, it's done. Rinse, dry it off, and you're all set. No heat, mixing, or fumes.

After I etch my boards (photo resist), I use Acetone to remove the resist. Then before I tin them, I'll use either 0000 steel wool or scotch bright pads to clean the copper. Degrease with rubbing alcohol, and into the Liquid Tin they go. Fast and easy.

http://www.mgchemicals.com/products/421.html

[The Tone God]

I use liquid chemical tinning solution as well. I wouldn't bother with anything else for DIY boards. I doubt it can get any easier.

Andrew

[keninverse]

Liquid tin is fast and easy but forget about reworking after a couple of weeks.  Then again houston is pretty humid; so oxidation here is always a problem.  The best method I found is tin with liquid tin then tin the through-hole pads with solder.

[Joe Viau]

I went to the MG Chemicals web page and found a distributor that is only 3.5 miles from me!

I've ordered a 4.2 ounce bottle and we'll see how it works out.  This sounds very promising.

Thanks for all the info,
Joe

[object88]

I've only worked with pre-fab'ed PCBs in the past-- what is this "tinning" of which you speak?  Thanks!

[Joe Viau]

Tinning means that you cover the copper traces of a PC board to protect them from corrosion.  If your PC board is small, it's a simple enough matter to heat up the traces gradually then melt solder over them.  But with more complicated boards, this becomes a hassle.

Most commercial boards that I've seen are covered with a green solder mask, which protects the traces.  I live near the ocean, so the air will get pretty humid in the warm weather and lots of things rust.  I used to live in Nevada, and you'd see 1955 Chevy pick-ups with very little, if any, body rot.

Some people feel that tinning / covering the traces is a waste of time.  Others swear by the process.  I think that the truth is somewhere in the middle.

[downweverything]

i use liquid tin and love it.  i dont have any oxidation problems whatsoever.  however the only place i can find it online is at allied electronics for like $30 a bottle.  does anybody know of anywhere else?