Any reason I shouldn't cast with lead that's been used to desolder electronics?

[salfter]

I have a bunch of computer motherboards, DIMMs, and other circuit boards available from which I'd like to desolder the chips and have a go at gold recovery. That's beyond the scope of this forum, but I think I've hit on a method that might impact my boolit casting in a good way, and want to determine if it's just a brain fart or if I might be on to something. :-)

The solder used in electronics assembly tends to be either an alloy of 60% or 63% tin and the balance of lead (for older stuff) or an alloy of 95% or more tin and the balance of silver and/or copper (mostly within the past 10 years or so). This is significantly higher than the alloy used in boolits, but if it's just an ounce or two added to a couple or three pounds of range lead ingots, the final mix might be sufficiently enriched with tin to harden it for use at faster velocities (like magnum handgun or rifle loads).

What I'm thinking of doing is something like this:



melt down a couple or three range-lead ingots in the pot I use for range-lead recovery
float a circuit board on the molten lead, component-side down
lift the board out, leaving the components floating on top and most of the solder mixed into the lead
fish out the components with a slotted spoon; set aside for gold recovery
repeat with more circuit boards
pour ingots with more tin than when we started


Does this look reasonable? The only impediment I can see might be electrolytic capacitors, which probably should be removed so they don't blow up in the pot. Also, will the inclusion of silver and/or copper in lead-free solder lead to any undesirable properties for boolit casting? Right now, it looks to me like (1) a free source of tin for boolit casting and (2) a faster desoldering method than using a blowtorch.

[rancher1913]

there are some places that you send the boards to and they do the melting and send you back a cone of metals, all segregated.

[5Shot]

Doing it that way is very toxic...do a google search on the towns in China where they do it that way.

[30Carbine]

Ok first off do you have a fresh air hood? if you don't all the plastics and resins you are going to melt are toxic. if you have some older boards that use phenolic formaldehyde resin, epoxy resins and fiberglass came later they melt at around 266-338 degrees F. my wife used to make circuit boards at a company that used to be around here there are some real bad things in them.. then there's the hole gambit of gold recovery and the chemicals and acids needed for that (and safety items needed) and yes I do that also but it is very controlled. I only do it a little bit now I mostly get my gold from my claims now (more effective)

[30Carbine]

As more effective this is from last Saturday when I got my backhoe up to the new claim. 4 feet down 1st 5 gallon bucket.






http://castboolits.gunloads.com/images/attach/jpg.gif

[hickfu]

as more effective this is from last saturday when i got my backhoe up to the new claim. 4 feet down 1st 5 gallon bucket.






http://castboolits.gunloads.com/images/attach/jpg.gif


nice!!!!

[georgerkahn]

I strongly agree re hazards from VERY toxic fumes!!! In addition, a few years back we removed the vacuum tubes from an old radio with water-damaged to be worthless wooden case, and tossed it into a fire. Some components -- possibly capacitors? -- exploded, with sound similar to a .22 being fired! Thankfully, the wood case had not burnt through, stopping anything flying.
Soooo, definite EYE PROTECTION should really be in order if you attempt this. Perhaps modern computer components do not pop -- but a pair of safety glasses worn surely provides cheap insurance.
One added note is that in "my day", when components were hand soldered, LOTS of solder was used. For me, I'd truly wonder if you'd get enough to make it worth its while with today's mechanical soldering, using just enough to stick two tinned surfaces together. Plus, with LSI, there are really very few, comparatively, soldered components.
BEST!
geo

[Geezer in NH]

Have fun and report, but seems why bother for the amount of recovery other than the I can do this bit but is it worth it?

[44magLeo]

I might rank that up there with trying to reclaim the lead from batteries. What you get out of it isn't worth the health risk to yourself or anyone near by.
Leo

[Four-Sixty]

I work with a fellow who worked for IBM. He says the plant that they worked at, making circuit boards, had a fire. The fumes were so toxic they sealed up the building. I think this was over 30 years ago, and he claims the building is still sealed up.

[JonB_in_Glencoe]

In the 1980's, I was a supervisor at a PCB assembly division of an industrial controls manufacturer.

First, I will say...I bet dollars to donuts that most of the components won't stay in the molten alloy when the upside down PCB is lifted...they will stay in the PCB.

Second, if I am wrong in my "First" statement, I am fairly sure, the new empty holes in the PCB will wick up lead alloy, and you are likely to end up with a overall loss of alloy, although you may have an increased percentage of Tin in your remaining alloy.

My guesses above come from a project I did at work, by recycling IC chips off computer PCBs by running them through the company's wave solder machine. Pulling the chips while the PCB was over the wave wasn't easy as you'd think, no way will they fall out/remain in the melt as you're hoping.

I'd think, if I was gonna try and reclaim some Gold or Platinum, I'd just cut all the components off the PCB, if they need to be removed.

[RogerDat]

Go to S&S section of the forum, spend less than $5 a pound for 90% tin alloy. Maybe as much as $5 a pound for pewter. Cost maybe $30 - $35 shipped for a 2.5 - 3.0 lb. shipped ingot. Not having to dink with solder recovery during your gold and precious metal recovery priceless.

I knew an old guy lived out in the country, made a re-burn chimney and would cut the contact edges off using a band saw, then put them in a cauldron, and burn them on a fire with the re-burn chimney to burn the toxic smoke coming off, guy was an engineer who liked making stuff like that. He also lived far enough out and on enough land that he wasn't caught so never had to go to court and pay big fines. He had several pallet boxes of the large computer boards with gold contacts down one side that made it worth while. By several I mean a pole barn full of them. Whole witches pot full of 18 - 24 inch contact ends would end up as pile of ash and little bb's of metal in the bottom. He was in his mid 80's so I don't think he was worried about dying young from the toxic ash or smoke. How about you?