Removing thermal glue from the Jaxman E2L

The E2L has a really nice grip, it is lighter than the S2+ and uses a triple, so puts out more light than a single LED due to higher efficiency of the LEDs at lower current. I bought one last year to check out the Nichia 219C 4000K, which is fine but not my favourite so I bought a KDLitker triple SST20 4000K. To install that I needed to file the MCPCB to 19.3 mm and remove the optic and old MCPCB. The optic was stuck and reading the old E2L topic thermal glue is used that only gets loose or soft at 100 C. Hmm, annoying. I finally started work on that a few days ago. As the optic was stuck too, I put the head upside down on a plate, and blew hot air on the outside with a heat gun/pain strip gun used to remove old paint.

I monitored the temperature with a multimeter with thermocouple. I managed to get the optic off with a very fine tool between optic and housing to pull it off at one side then wiggle it off, while it was still hot.

The MCPCB was harder, I decided to heat up the housing to 140C, then used pliers with thin round ends as used to rotate the tightening rings for driver and/or switch in most pocket lamps, to rotate the MCPCB using 2 of the 3 the holes for the optic. Then cleaning up the remainder using tools it all came off easily in the head, harder on the bottom of the MCPCB. Perhaps thinner would have worked better than removing a bit at a time with fingernails on the MCPCB.

Something weird that happened is that one of the LEDs broke off the MCPCB when I was removing the last bits of thermal glue from it. It looks like the solder broke, as if it was a cold joint, but perhaps a mechanical break can happen at around 100 degrees C? It must have been a lot less than 140 C already.

For me it doesn’t matter, I will replace the LEDs with others in due course, possibly the 519A.

63/37 solder has a melting point of 183C, which is one of the lower temperature solder that can be used to reflow LEDs.

I’ve found though that flashlight manufacturers usually use much higher temp solder (due to less or no lead solder) since my reflowing hotplate (electric skillet) maxes out at 425F (218C) and is not enough to remove the LEDs.

Of course the melting points of solder are much higher than 100C, but my point was, is it possible to break the solder layer mechanically without too much force at say 100C, i.e. does that weaken the solder? I’ve not experimented with such things, but wondering if anyone knew or had similar experiences. That would explain the solder break. Otherwise it was a bad soldering job of the LED onto the MCPCB.

I tried something like that recently cuz I was getting impatient. I was able to pull the wire off its solder pad on the board but the whole solder pad came with it

Side note, is this board still usable if I solder to the other pad

Just check to where the other sections of the traces go, you can usually make it out from the height difference. You could scrape away a bit of the the white insulating layer, then use a multimeter’s LED testing function. If that lights up the LED you have the right area and you can scrape away a bit more and then solder to that.

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