DIY tin plating

[AudioWizard]

Hi all,

I was thinking about trying tin plating PCBs the "hard way". That is, making some Sn alloy melt in an ad hoc pan, then once it's all nicely melted, plunging the PCB in it for a few seconds (maybe just making it "float" above the melted alloy would be good). Pre-heating the copper might help too.

Has anyone tried it yet? I was thinking about using some soldering alloy with no Pb at all to do this (97% Sn, 3% Cu).

It doesn't seem that hard to do; any idea/advice?

[dnsey]

http://www.diybanter.com/q-t_94795-Tin-plating.html

[Sch3mat1c]

You'll burn the board. Use 60/40 or 63/37. Coat the bottom of the board with rosin, dip it, oh and mind solder bridges if you have *any* close joints!

Tim

[AudioWizard]

Originally posted by Sch3mat1c
You'll burn the board. Use 60/40 or 63/37.

Well, what if I want to make a Pb-free PCB? ;-)
Not sure that the difference in temperature would change much in just a few seconds anyway. Thing is, I don't know how many seconds would be required. I have to try.

Originally posted by Sch3mat1c

Coat the bottom of the board with rosin, dip it, oh and mind solder bridges if you have *any* close joints!

Well, I think using flux would help, but would also make solder bridges more likely.

Anyway, if no one tells me "don't do it, it's too dangerous", I will give it a go and report back with the results.

[Sch3mat1c]

Lead free? Pffbt... I have a few words of inadequacy for you, but I cannot use them here.

Heck, standard practice for industry: wave soldering machines. Just don't drop it or generally get it on yourself; tongs would be a good idea.

The circuit board ought to float in a worst-case scenario, but don't trust me on that one, keep a hold on it at all times.

Tim

[sam9]

This stuff is a LOT easier:

http://cool-amp.com/coolamp.htm

And, for me anyway, it works pretty well.

[Marc´o Polo]

Or you can use this one( Sur Tin) from Bungard:

http://www.bungard.com/seiten/m_chem.htm#top9

[AudioWizard]

Thanks guys.

Basically, the idea was that I am unhappy with the usual cold tinning solutions (chemical), but I do want tinning on my PCBs.

I had seen this "Cool-Amp" stuff earlier, but it does seem pretty nice indeed. Worth a shot, I guess. I'm bookmarking it and will give it a try later if I get around to ordering some.

As to lead-free: why do you think it's "inadequate"? I'm not obsessed with environment concerns in the least, but I'm still trying to switch to lead-free circuits. At least in Europe, it's going to be mandatory anyway starting next year. I guess this won't apply to DIY'ers, but only factories. But still...
Besides, I'm thinking 97% Sn/3% Cu has better conductivity than the regular 60% Sn/ 40% Pb? And the melting temperature is not that much higher (like 20-30° higher, I think).

Oh, and as to the risky side of my tin plating in melted tin, I think I was more afraid of the possible fumes: are those likely to be toxic, especially if the temperature is not well controlled? Are those flammable?

[TwoSpoons]

I 'tin' my boards like this:

1/ spread a very thin coat of solder paste (the sort used for SMT reflow) over the whole board. I use a spreader made from a bit of cardboard, so I can throw it away afterwards.

2/ wrap some desoldering braid around a fat soldering iron tip.

3/ set the iron to about 300C then wipe it over the whole board

The paste fluxes and tins the copper beautifully. Any excess solder can be mopped up with fresh desoldering braid.

If you don't have paste you can use liquid flux, and preload the braid with ordinary solder.

I get extremely good results with this method. No mucking about with plating baths either!

[AudioWizard]

Thanks for the idea, TwoSpoons!