desoldering potentiometer wires??? - Page 1
Forum section: electronics / general

author: coppercone2
author_rank: Super Contributor
timestamp: June 11, 2025, 11:09:53 pm
content: How the hell do you desolder potentiometer wires? I did some cleaning and took apart a few pieces of test equipment that are just not gonna be fixed (and i don't like them) but inside they have copal brand potentiometers with wires that are wrapped around solder terminals (with hole).I managed to destroy one because the lead became wobbly after about 2 seconds of heat.Is there some clever way to desolder them? Because my plan right now is to use a file and very carefully file off all the solder. I can't really use water because its right up against the chassis and I don't want water in the sealed potentiometerI thought maybe some lower melting point solder alloy to try to dissolve the solder that is there, like woods metal?I never understood why people do 3 turns on a lead when its obvious that the wire will break near the insulation and even a lap joint on the solder terminal is never going to crack, let alone a single turn.They have zero resistance to heat and its a chore to even try to get them ready for the parts junk box.

author: langwadt
author_rank: Super Contributor
timestamp: June 11, 2025, 11:19:44 pm
content: cut the wire at the pin and leave the rest?

author: coppercone2
author_rank: Super Contributor
timestamp: June 11, 2025, 11:36:35 pm
content: then how am I gonna use it for something I want to build nicely??

author: coppercone2
author_rank: Super Contributor
timestamp: June 11, 2025, 11:40:03 pm
content: and they also have a power resistor in there that has like insulated wire that is entombed in solder around a heavy gauge wire. How shoddy for japanese construction. They wrapped the wire insulation into the solder joint with 2 other wires there and it looks like one of those solder boogers you pull out of a desoldering gun with plastic in the solder joint

author: thm_w
author_rank: Super Contributor
timestamp: June 12, 2025, 12:34:10 am
content: Quote from: coppercone2 on June 11, 2025, 11:09:53 pmThats why you cut the wire first, as suggested, remove the pot from the chassis. Then you have access to do whatever you want.If its going in the junk box there is a good chance its not going to be used, so I wouldn't put a ton of effort into it.

author: jpanhalt
author_rank: Super Contributor
timestamp: June 12, 2025, 12:46:45 am
content: Rather than use a solder sucker, use a blast of compressed air to blow the molten solder while wiggling the wire. In the early 50's, I did that to disassembly discarded TV's. In those days, assemblers had a solid mechanical joint before solder was applied -- quite the opposite of SMD.

author: 5U4GB
author_rank: Super Contributor
timestamp: June 12, 2025, 01:06:24 am
content: Not a terribly good solution but the closest I've got in the past is iterations of { solder sucker, cut everything thus exposed with flush cutters }. Eventually you either remove enough solder+wire to make a new connection feasible or get tired of it, declare victory, and also make a new connection.

author: coppercone2
author_rank: Super Contributor
timestamp: June 12, 2025, 01:07:23 am
content: ok compressed air maybe can expose the wire more so its easy to file or snip at

author: tooki
author_rank: Super Contributor
timestamp: June 12, 2025, 09:22:07 am
content: Use a heat sink? Radio Shack used to sell little aluminum clamps specifically for that purpose. You could even just drape a wet paper towel over the part, practically in contact with the solder lug, to keep it cool.

author: coppercone2
author_rank: Super Contributor
timestamp: June 12, 2025, 10:51:08 pm
content: I have that its way too shortthis design can go to hell, it involves blowing or grinding solder making a big mess. They could have made it a little longer or used better plastic IMO, its basically single useand it has so much solder on it that even if I got a thinner heat sink clip, it is sitting on a big lump of solder which is pushed against the plastic wallwhy is the old 1960's potentiometer equipped with 2x as thick and 4x long solder points that don't have this problem? And the old ones have a bend in them so you have a clear place to put a thermal clip. they had to shave every fucking penny out of thisbut IMO this DC load is a load of shit anyway, none of the connectors are keyed, the wiring colors is non obvious, there is massive use of 'hardware structures" (i.e. washer stacks to act as standoffs), extremely gnarly soldering and dubious solder constructs/structures (circuit card vertical maze) in it... adhesives... like low quality ATX power supplies. I wonder if the only thing that draws me to these potentiometers is clever use of damping grease that makes them feel expensive lol

author: tooki
author_rank: Super Contributor
timestamp: June 13, 2025, 09:39:35 am
content: So try draping a wet paper towel over the plastic to keep it cool.

author: coppercone2
author_rank: Super Contributor
timestamp: June 13, 2025, 06:49:07 pm
content: maybe a cloth with a cut in it so the lead comes out of the hole and draped over the whole part

author: jpanhalt
author_rank: Super Contributor
timestamp: June 13, 2025, 07:20:42 pm
content: You used to be able to get asbestos putty for that. Now, I use stips from old T-shirts wet and just wrung dry. The slot is probably inferior to wrapping a narrow wet strip or wet cotton string (butchers twine,etc.). You can wrap those pretty tightly to get good contact. And of course, if using compressed air, you want something that is not your finest table cloth as a backdrop.

author: helius
author_rank: Super Contributor
timestamp: June 13, 2025, 07:26:50 pm
content: Quote from: jpanhalt on June 13, 2025, 07:20:42 pmI've never seen asbestos putty and am unsure how you would use it, but heat-resisting putty is still made and sold for plumbing and jewelry users. You should find it if you search for "sta-cool putty" or "keep kool" or whatever trademarks they use.

author: coppercone2
author_rank: Super Contributor
timestamp: June 13, 2025, 08:05:12 pm
content: I have a bucket of that but it did not occur to try to cool the plastic, i always think about heat sinking the metals. There is like no way to get contact on the metal part unless you basically totally submerge it in water so the metal is contacted by the water surfaceif cooling the plastic is enough with putty or cloth it might work but I have my doubtsI got three potentiometers leftWhat would be good is like a blunt cutter head made out of aluminum so two aluminum wedges clamp down hard on the very end of the potentiometer with like a 1mm flat.I wonder if that could be a viable product, the idea is to sell a rubber band with aluminum head that can be mounted to a pair of smallest knipex parallel jaw pliers to turn them into a thin heat sink clip that is optimized for blocking heat on flat thin objects, or maybe nickel plated copper head.Then ideally you would have different heads of thicknesses from 0.5mm to like 3mm so you can clamp on whatever is 'left'.Too bad it sounds like a months work to figure out for a $5 potentiometer rescue lolthat is a entire tool box of high performance optimized heat sink clips, including different round clamps and different beaks so you can set up the clamp in anything you are working on.'I just know for sure when we have cheap metal 3d printers someone is gonna print a set eventually.Very similar to the tool I imagined when I thought about what the most proper clamp for bending axial components like capacitors would look like...Right now we have a gigantic assortment of wire handling tools. Is the future strip handling tools?Strip is interesting because its a more modern process then wire, I think it took off in the 40's when they figured out how to do electro-made strip in chemical baths... not much heavy machinery to manufacture that in comparison to wire. It is the same as wire tools but requires the parallel mechanism to be any good.

author: tooki
author_rank: Super Contributor
timestamp: June 14, 2025, 08:56:32 am
content: Quote from: coppercone2 on June 13, 2025, 08:05:12 pmWell the plastic, not the lug, is what softens as it heats up, causing the lug to loosen up, so why is it surprising that keeping the plastic cooler would prevent it from getting soft?Water has high specific heat, meaning it needs lots of energy to heat up. That makes a wet cloth a great heat sink.