Box of broken computer parts - anything useful ?

Power supplies may be useful for powering projects in the future.

Any heatsinks you can salvage would be good to have in your junk box.

Maybe cut off any pigtails of stuff you don't plan to keep. You might need the connector at some point.

Thank you. All parts, including PSUs are dead, cant use them anymore. Thanks for the heatsink tip, i will recover those, i often need them. But i was wondering if its worth timewise/moneywise to salvage the big 230V caps, AC/DC converters, coils and other elements i dont recognise.

I suspect the large capacitors are more likely to be 450V type (unless specifically for the US market) so the supply is dual 110/230V switchable. I would suspect that most of the other parts aren't salvageable as they are unlikely to use removable modules (such as DC/DC converters) and it'll be part of the overall design.

Mike.

Not to make a new thread i will ask here. A while ago i remember seeing a video about salvaging interesting things from old electronics. I belive the overall goal was to remove parts from the pcb and afterwards also salvage what little gold is there. I am not interested in gold, i am interested in solder though. I remember them using an acid to remove solder and i was wondering if anyone knows which acid it was or how to salvage solder in some other way.

I ask because i find myself often using solder as a temporary thing, or to just hold things in place, test, etc. And for that, old dirty solder is perfectly usable with my cheap solder paste. Solder is quite expensive where i live, 100 grams is like 8$, so it feels waste to use it for things where u use lots of solder and then 2 hours later throw it all away.

SentinelAeon said:

Not to make a new thread i will ask here. A while ago i remember seeing a video about salvaging interesting things from old electronics. I belive the overall goal was to remove parts from the pcb and afterwards also salvage what little gold is there. I am not interested in gold, i am interested in solder though. I remember them using an acid to remove solder and i was wondering if anyone knows which acid it was or how to salvage solder in some other way.

I ask because i find myself often using solder as a temporary thing, or to just hold things in place, test, etc. And for that, old dirty solder is perfectly usable with my cheap solder paste. Solder is quite expensive where i live, 100 grams is like 8$, so it feels waste to use it for things where u use lots of solder and then 2 hours later throw it all away.

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No metal is soluble in an acid as an elemental metal or alloy - it needs to be oxidized and dissolve as a metal ion. Since metal ions are positive ions, the metal needs to be oxidized as it reacts with the acid and dissolves into the aqueous mix leftover from the reaction.

Once you have dissolved tin (and lead), you'll need to isolate it from the acid and find a reducing agent or electrochemical process to turn it back into a metal. Then convert it from the powder, platelets or needles you get from the reducing process to a usable form (wire or molten pot of solder) is another chore - especially if it is contaminated with other salts from the reduction process or the starting acid.

At this point, I'd say $8/100g is a good deal. Buying acids can be quite expensive because of the hazardous goods packaging and shipping premium and all the weight.

Got to admit it sounds intriguing, though not very practical for my situation. Still, it would be fun to throw all i have into a big pot (about 15 motherboards, about 15 broken power suplies) and just get out the dust. Then just use heat to get an ingot that i can use.

How about heat ? A power supply board has tons of interesting elements on it, like big caps, mosfets, etc. The problem is that if i go about removing each individualy i can do this for the rest of my days. So i just keep those boards in a big box as a backup, sometimes i need certain element in the middle of the night when shops are closed.

But solder on those PSU boards ... my god, it pains me to throw all that nice solder away. Some psu boards seem like there's a 100 gram solder pack on it. But i dont know of any easy way to get it. I could use a wick but then i have solder on wick - which is usable to connect pins on board. I have seen someone just use vacuum pump, either directly on the solder or first use wick to get solder on it, then use vacuum to recover solder

You could try putting it inside a heavy (stainless steel) pan and set it in your bar-b-que grill. It should start melting at 425°F and start to flow at 600°F so you'll really need to heat it. Below 500°F, it will tend to hang on to any copper surface and not flow. I'd do it outside - the FR4 board gives off some nice odors when you heat the board all the way up to those temps and hold for a while.

Anything vaguely recent will have lead-free solder. You'll spend a lot to get crappy solder.

For The Popcorn said:

Anything vaguely recent will have lead-free solder. You'll spend a lot to get crappy solder.

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And it won't be flux cored either, so making it pretty unusable - it's a pretty silly idea all round.

I have a lot of cheap flux to combine. And i find myself often making temporary fixtures and its such a waste to spend perfectly good solder for that. And sometimes i just want to combine 2 metal parts and would like to test whether that would be an option. For all permanent electronic things i use brand new solder.

Heating the whole board with elements would be possible but that would probably kill most, if not all elements on it. 600F i think is way over what elements can handle. But if we leave the elements aside. If the board is heat up to 600F, will the solder drop from the board itself or will i still have to do the shaking of the board, which is dangerous, even when i wear full protective gear ?

SentinelAeon said:

I have a lot of cheap flux to combine. And i find myself often making temporary fixtures and its such a waste to spend perfectly good solder for that. And sometimes i just want to combine 2 metal parts and would like to test whether that would be an option. For all permanent electronic things i use brand new solder.

Heating the whole board with elements would be possible but that would probably kill most, if not all elements on it. 600F i think is way over what elements can handle. But if we leave the elements aside. If the board is heat up to 600F, will the solder drop from the board itself or will i still have to do the shaking of the board, which is dangerous, even when i wear full protective gear ?

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I've never tried heating to 600°F but my materials guy claims it should flow from the board at that temp. You'll have to do a test to prove him right or wrong - he said it's not worth the effort as you may oxidize some of the tin and the tin oxide crystallizes will stay on the surface of each solder bead and will have to be filtered from the mass of tin before reusing it. The tin oxide will make weak bonds and change the apparent surface energy of the melted tin (it may bead up and roll off the copper pads or copper wires. Again - that's his theory and you'll have to try it to see if he's right because he thinks your plan is a waste of time and resources, not to mention dangerous.

He recommends blanketing in nitrogen but doubts you'll have that next to your bbq grill.

ZipZapOuch said:

I've never tried heating to 600°F but my materials guy claims it should flow from the board at that temp. You'll have to do a test to prove him right or wrong - he said it's not worth the effort as you may oxidize some of the tin and the tin oxide crystallizes will stay on the surface of each solder bead and will have to be filtered from the mass of tin before reusing it. The tin oxide will make weak bonds and change the apparent surface energy of the melted tin (it may bead up and roll off the copper pads or copper wires. Again - that's his theory and you'll have to try it to see if he's right because he thinks your plan is a waste of time and resources, not to mention dangerous.

He recommends blanketing in nitrogen but doubts you'll have that next to your bbq grill.

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That blanketing in nitrogen got me I guess i will just keep a couple of boards for spare elements when i need them and forget about recovering solder. It always feels like a waste to throw away perfectly good stuff and then buy the very same stuff. But sometimes buying is the smart solution. Tnx for all the answers

SentinelAeon said:

That blanketing in nitrogen got me I guess i will just keep a couple of boards for spare elements when i need them and forget about recovering solder. It always feels like a waste to throw away perfectly good stuff and then buy the very same stuff. But sometimes buying is the smart solution. Tnx for all the answers

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I don't recommend it - even if your in the middle of nowhere with limited access to parts. Deigning an electronic circuit with the right parts for the application and stumbling upon the right part in your bin is just like throwing darts blindfolded. Not to mention the effort of finding them and desoldering them. I just to keep some boards and ended up tossing them when I realized 10-years had passed and not a single part was ever used except for a few pots and heat sinks.

I have a few boxes of surplus 5mm LED 200/bag. ultra high efficiency 4500 'K 30 deg > 16,000 mcd and some amber yellow worth a few $k and a reel of tape mounted std-red LEDs.
Anyone ?

ZipZapOuch said:

You could try putting it inside a heavy (stainless steel) pan and set it in your bar-b-que grill. It should start melting at 425°F and start to flow at 600°F so you'll really need to heat it. Below 500°F, it will tend to hang on to any copper surface and not flow. I'd do it outside - the FR4 board gives off some nice odors when you heat the board all the way up to those temps and hold for a while.

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Temperatures that high would bake the salvageable components, becoming e-waste.
Using a BBQ as an incinerator could violate local environmental regulations and warranty. Electrolytic capacitors explode in high heat ( it happened to me, no injuries), and could be mistaken for gunshots.