Stripping motherboards - pins per socket yeald experiance

[patnor1011]

You can cast environmentally friendly fishing sinkers from tin. :mrgreen:

 

[Sodbuster]

Pat :
We can't even do that, still got plenty of lead to deal with. Although it is still higher in tin or bismuth that lead is still at better than 30%. Silver isn't even mentioned. We would likely find cadmium before any silver.
I guess we could make a boat anchor with it, :lol: just have to make sure we pulled up and took it with us. To me it will always be dirty tin i guess.

Ray


( clipped out of Wiki )

Common solder compositions
Different combinations of tin, lead and other metals are used to create solder. The combinations used depend on the desired properties. The most popular combination is 63% tin, 37% lead. This combination is strong, has a low melting range, and melts and sets quickly. Higher tin compositions gives the solder higher corrosion resistances, but raises the melting point. Another common composition is 11% tin, 37% lead, 42% bismuth, and 10% cadmium. This combination has a low melting point and is useful for soldering components that are sensitive to heat.

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

 

[Goldfinger4]

Silver solders melt above 650 °C, you would destroy your board with that. I think electronic stuff is always soldered with tin/lead solder (before 2006 in Europe).
I don't know American laws but if your old boards are already lead-free the solder contains >90% Sn and max. 4% Ag.
But Sn bars also look nice, I always collect the tin filling from silver knives

Btw old silver solder is often sold on ebay..

 

[vovikk]

Hey, everybody!

Got my 30-pcs mothermoards purchase arrived .
They are all now ready (all detachable parts are taken off - ICs, memories, jumpers, batteries, etc.)

Hope to do my processing job for this lot in a couple of days - doing some foto-video reporting stuff.
Also hope it will be interesting for somebody to have some more info on my method.

Will get back as soon as i will have something to post....

 

[TigWiz]

I'm looking forward to an update.

 

[nivrnb]

Vladimir,

Really like your post reminds me of how I used to collect parts, but I never took photos of what I was doing. The bad part for me when I used to do this is that I would have the heat up to high and the boards would burn, and the smoke would just follow me. I would stand in different location away from the oven to see if I was just me or not. The smoke always followed me. Then I got a fan to blow it away from me. I think I am feeling the effects of those days or maybe its just old age. I hope old age :mrgreen: .

 

[vovikk]

Vladimir,

Really like your post reminds me of how I used to collect parts, but I never took photos of what I was doing.

:_) thanx

Vladimir,

The bad part for me when I used to do this is that I would have the heat up to high and the boards would burn, and the smoke would just follow me. I would stand in different location away from the oven to see if I was just me or not.

oh, that's absolutely true!
I am trying to choose windy days (i even worked when a pretty thunder rain felt for an hour at least....)
Otherwise the smoke (often unvisible but .... ) is making me sick.

 

[Barren Realms 007]

Vladimir,

Really like your post reminds me of how I used to collect parts, but I never took photos of what I was doing. The bad part for me when I used to do this is that I would have the heat up to high and the boards would burn, and the smoke would just follow me. I would stand in different location away from the oven to see if I was just me or not. The smoke always followed me. Then I got a fan to blow it away from me. I think I am feeling the effects of those days or maybe its just old age. I hope old age :mrgreen: .

Repeat 3 times: I hate white rabbit's, I hate white rabbit's, I hate white rabbit's. And the smoke will go away. 8)

It an old trick we use to use around the camp fire.....

 

[g_axelsson]

Silver solders melt above 650 °C, you would destroy your board with that. I think electronic stuff is always soldered with tin/lead solder (before 2006 in Europe).
I don't know American laws but if your old boards are already lead-free the solder contains >90% Sn and max. 4% Ag.
But Sn bars also look nice, I always collect the tin filling from silver knives

Btw old silver solder is often sold on ebay..

The silver solder found on circuit boards are based mainly on tin with only a few percent silver. Ordinary tin - lead solder (Sn 60% - Pb 40%) melts at 183 C while tin silver (Sn 96,5% - Pb 3,5%) melts at 221 C.

I got an idea, maybe Parkes process would work with tin too? I did a search and found this report which uses zinc to form silver zinc alloys that solidifies while the tin phase is still liquid. With four repititions they recovered over 70% of the silver in an experimental setup. Maybe it could be used in an economical way to recover the silver from old solder. The resulting tin should be pure enough to be used in an electrolytic tin refining cell, the anode sludge would contain the rest of the silver. I wonder where the dissolved gold ends up, with the silver or the tin?
http://www.jim.or.jp/journal/e/pdf3/51/07/1350.pdf

Göran

 

[gmandoit]

Just jumping in guys but the tin solder ingots I believe you can reuse for future stannous solutions I'm excited to be on here and hope to soon show some bit of work I have been doing with success of precipitation but I have yet to put the flame to the pudding

 

[solar_plasma]

I wonder if it would make sense to electrorefine solder tinbars, maybe not today, but in some years. Electrolyte SnCl2, if it is cold enough, most of the leadchloride might stay in the anode bag,together with any silver, - if there is silver at all. A fairly pure tin gives about 9€ (purest tin even more, since spot is 22€), while lead only 0,60-1,10 (spot 2€) €.

Not a new idea, but the tin prices are still raising and even ESG in germany is interested in tin also in smallest amounts.

I see a big problem in the poisonous vapors released from a PCB at 200°C.

Another maybe dumb idea: Maybe collect the solder with cheap lead. But again vapors....

Any thread I read about approaches of wet processes ended with a great mess...


Any assumptions or experiences?

 

[Pantherlikher]

Years ago I used a kerosine/ air fired tube heater, torpedo heater. It worked great with alittle practice. A large metal sheet pan caught solder as it dripped.
Another flat pan caught everything when I smacked the board against the pan.
When practiced, you could melt the solder and drop every 5-10 seconds. Any longer in the flame and the board started smoking to burnning.

The wet way is messy. I was mass dissolving in poor man's AR before finding this site. Was major volume and alot of lost PMS. But as I finished with dropping from the AR, I would put some Aluminum in the solution slowly as it is violent and gets extremely hot. This dropped everything above it, copper +.
Then I'd pour into a large plastic square bucket that fit mother boards. After a day in there, everything fell off the boad and then rinsed in HCL and water and seperated.

The whole project worked but there ended up being several 5gal. bottles with spent solution and alot of water. The book I bought to learn had nothing for dealing with the waste. Unfortunately, the now "X" desided it was ok to demolish and remove the garage and it's contents... Dumped went everything including a large jar of powders.
So, under the new parking lot of my 1st home is a nice treasure waiting to be found. With alot of nasty Chlorides.

B.S.