Is it possible to remove solder from brass threads?

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negev
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Is it possible to remove solder from brass threads?

I’m a total noob to modding and decided to swap the driver and mcpcb from an S2+ (with old-style threads) into a new S2+ with the new-style threads.

Drilled the pill, swapped everything over, all good. Then just for completely I tried to swap the driver and LED that was in the new S2+ and ended up getting solder on the threads of the pill. Spent a fair bit of time trying to get it off with some desolder braid but was unsuccessful.

Is there a trick to this other than “don’t get it on there in the first place”?

I had a reflow heat gun but it was useless even at max heat. Also melted its own plastic shroud in short order, I think I’ll be sending that one back.

Firelight2
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Soldering iron or reflow heat gun with a good vacuum solder sucker might work.

Or you can try removing the excess solder with a handfile or sandpaper.

Sirius9
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No tricks unfortunately.
If you have low melting point solder you can mix it with the solder on the pill and when you get it heat enough you can wipe it with q-tip, tissue or something similar.
I usually scrape it with exacto knife.
P.S. I presume you got it on threads inside the pill, where driver goas! You can scrape it as mentioned and then screv in by force the brass retaining ring for driver, if you have one.
Brass is harder than solder and will not be damaged.

 

Henk4U2
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The S2+ pill has two threads: a coarse thread on the outside and a very fine thread on the inside (for the retaining ring).

For the coarse thread I would use an exacto knife (Stanley knife, as we call it in NL). The pill is harder than the solder. Think of it as carving wood. You’ll get there …. eventually.

For the fine inside thread you can use a very sharp exacto knife, or a very sharp needle. Apply the same attitude Wink

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NeutralFan
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I wish there was a way to remove all of the solder, but it seems to be impossible beyond scraping or sanding away. Solder wick or a solder sucker will still leave behind a small layer of solder.

I’d rather use my flashlight around the house than turn on the lights.

AlexGT
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I was thinking of maybe using a brass wire brush with a hot air reflow station, but I don’t think it will get it off completely.

Correllux
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Sometimes you can just pick/scrape it away as mentioned above.

Have you learned yet that “Flux is your friend!”…? It really is. With solder wick, some of that comes fluxed and some does not, but it usually helps to add more directly to the braid before you begin to heat things up. It’s just as helpful when desoldering as it is when initially soldering.

Next is heat transfer and this is the bane of most soldering problems. The tip needs to be clean – if it’s been allowed to get badly oxidized from heating too long, heating dry, residue from solder and rosin, etc, etc, then clean it up and re-tin it. If you can’t get it clean then sometimes the $$ re-tinning paste will work (the stinky ammonia type). Also, a tip some never learn is to apply a tiny drop of fresh solder to the tip before you start to desolder or rework…aids a lot in quick heat transfer and overcoming any resistance from oxidation, etc.

Tip size can be helpful, too. If you’re using one of the typical small points then a “hoof shaped” tip or a larger chisel tip might help you out here just by having more mass and carrying more heat to the point of contact – that can be important when you’re working on a big heat sink like a brass pill. Increasing heat can help, too, but that shouldn’t be necessary if all the above is in order, although lead-free solder takes more oomph. Actually it was recently explained to me that non-eutectic solders need considerably more heat to remelt than they did when first applied…interesting. I really like the hoof shaped tips for lights since their angle makes it much easier to poke down onto a led board and the smaller ones are usually fine for work on drivers, too.

Hank33
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Oh yeah anything is possible. Just look at the olympics for example. Gold medal!!! Cash

negev
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Thanks for the tips guys, I’ve been too busy to look at it again but might see if I can gradually sand it off with sandpaper. It’s only a little bit that’s blocking the threads from turning at the top.

Henk4U2
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negev wrote:
Thanks for the tips guys, I’ve been too busy to look at it again but might see if I can gradually sand it off with sandpaper. It’s only a little bit that’s blocking the threads from turning at the top.

I don’t know how the solder accident happened. My best guess is during desoldering a 4+ AMC7135 driver. In that case the solder will be stuck on the (fine) inside threads. Beware, sandpaper is very abrasive. If you remove the solder with sandpaper, chances are you also remove the threads.

Last resort! A frying pan. Put the pill in, with the fine threads facing down. Heat up the fire till cold drops of water “explode” in the pan and wait a minute ore so at that temperature. Then grab the driver and tap it, fine threads facing down, on a piece of wood (4”×1” or so). If necessary, repeat the procedure. Or up the temperature.
Try prying out the remaing solder from the threads with a sharp needle.

The old saying is: don’t try this at home. This time it is: don’t try when the missus is at home.

You are a flashaholic if you are forced to come out of the closet, to make room for more flashlights.

negev
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The inner threads don’t matter on this one because the driver is soldered in, the problem is the outer threads. When soldering the driver into place I was a bit cack-handed and got some solder on the threads at the top of the pill which cause it to not screw in.

Correllux
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I’d recommend a little needle file rather than sandpaper. Even the cheapie cheap China needle file sets are fine for this. Triangular usually the best choice but the sets have a variety, some with safe edges (or you can grind them safe if you like). Better precision and control so you don’t damage the threading. Don’t give up on your iron yet, though, imho.

negev
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Will try again with the iron. I have a new one just came today, the first one melted it’s own shroud in about 20mins.

sp5it
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Use HCL to dissolve it.
Or:
3Sn + 4HNO3 + H2O = 3H2SnO3 + 4NO
Sn + 4H2SO4 = Sn(SO4)2 + 2SO2 + 4H2O
Sn + 4H2O + 2KOH = K2[Sn(OH)6] + 2H2

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kennybobby
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+1 sp5it, i’ll have to try some of these acids—better living thru chemistry…

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drivin' around on fossil fuel,
until i saw what i was doin',
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Firelight2
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I suppose another option would be to:

  • Remove all electronics from the pill so you have just bare brass.
  • Heat the entire pill up with a blowtorch
  • Use a powerful vacuum solder sucker to remove the solder.

Probably easier to just scrape it off with a small handfile and x-acto knife though.