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When modding electronics it is usually recommended to apply copious amounts of hot glues when you solder a wire to a board contact pad to prevent accidental removal of said pad from the board..

I did that, but now something does not work and I want to inspect/redo the solder.

What is the best way to remove hot glue mess from a delicate wire/solder pad without melting things around and or damaging the board?

delicate solder

(Image credit)

If you look closely on the bottom left points, the point with copper for solder are tiny blobs 1 x 1.2mm which must have conductive paint scratched from it, so it is already pretty beaten even before any repairs.

enter image description here

(Image credit)

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    \$\begingroup\$ Careful application of a hobby knife. \$\endgroup\$ – Ignacio Vazquez-Abrams Oct 28 '14 at 5:28
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    \$\begingroup\$ There's nothing "off-topic" about a bench technique question! \$\endgroup\$ – Chris Stratton Oct 28 '14 at 15:05
  • \$\begingroup\$ I'd spend a fair bit of time probing it to make sure it's bad before proceeding. And maybe avoid the issue by finding another place to solder to if it's actually open or intermittent. For future reference, apply the adhesive (epoxy or hot glue) to the wire as a strain relief rather than over the joint- leave the joint exposed. \$\endgroup\$ – Spehro Pefhany Nov 24 '15 at 16:49
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I have seen technicians remove hot glue by swabbing the area with rubbing alcohol. Rubbing alcohol is also known as isopropyl alcohol. This doesn't really dissolve the hot glue, but causes it to come loose from the board and wire. In future, instead of covering the solder with hot glue, consider if you can apply the hot glue away from the solder area. The main purpose of it is to provide strain relief. It doesn't have to be right on top of the rework area.

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  • \$\begingroup\$ that is the best advice. keep hot glue away from the solder joints. \$\endgroup\$ – gcb Oct 29 '14 at 3:25
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Put it in the freezer overnight. Hot glue will both contract in the cold and lose it's adhesion. You can then chip it off while it is still cold.

Cold spray doesn't work - it will quick-chill the surface but the core (and part sticking to the board) will still be warm.

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  • \$\begingroup\$ I did a combination of everything here. Put in the freezer. soaked in isopropyl alcohol. and then had the idea of cutting the wire attached to the pad very short and press it against a soldering iron tip and let it burn... well. it did work for one point... that was soldered fine so i think there is a problem on the board. and another left the board with the pad attached to it... sigh, which also led me to believe the solder was fine to begin with... i think the only way to win against hot glue, is to not play. \$\endgroup\$ – gcb Oct 29 '14 at 3:27
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    \$\begingroup\$ This is actually the reason that hot glue is terrible for production use. Cold temperatures make the bonding interface go completely brittle to certain materials (like PCB). I've seen boxes upon boxes of chinese factory modified products go in the trash because they did this, then sent it halfway around the world in a shipping container that gets really hot and really cold. \$\endgroup\$ – Daniel Nov 24 '15 at 23:13
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MEK (methyl ethyl ketone) will dissolve at least some hot glues, but unsure how it would react with other components (asshat who owned my house previously used hot glue as caulk to seal all the storm windows shut, so did some experimenting)

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  • \$\begingroup\$ en.wikipedia.org/wiki/Butanone#As_a_solvent interesting. easy to get and dissolve lots and lots of polymers. thanks. (although i'm almost sure in a circuit board it would probably destroy the printed mask the green cover and possible the cables insulation :) \$\endgroup\$ – gcb Aug 16 '15 at 17:55
  • \$\begingroup\$ Always use gloves (with invisible glove cream underneath) and either a respirator or VERY well ventilated area when using MEK. It absorbs into your skin and can damage your liver :( \$\endgroup\$ – Daniel Nov 24 '15 at 23:15
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Reheat the hot-melt glue with a SMT hot air reflow iron. Use an adjustable one, and turn the heat down significantly. When the glue is liquid, blot and wipe away with paper towel, cotton swab, etc. You can get most of the glue up this way.

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In the absence of Isopropyl Alcohol I turned to an old favourite - my wife's nail polish remover. It takes just a few minutes to release the grip of hot-glue from most surfaces. Please REMEMBER to work in a WELL VENTILATED area.

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