Is it a good idea? Want to get a v3 from a 20mm mcpcb to a 16mm
Reflowing LEDs is one of the most basic parts of flashlight modding.
I understand that, but I’ve never heard of it being desoldered then transfered to another mcpcb, didn’t know if there was something more to it then I was aware of
It’s definitely a thing. The Samsung LEDs I got actually said something like solder limit of 2 times. I guess its possible if you do it enough times it could be damaged, but removing them is the same as putting them on. If you use a skillet or hotplate you can heat up both MCPCBs at the same time, then just pick the led up and drop it on the other board when the solder starts to flow.
Oh ok cool, so wouldnt I need to get more solder paste?
I corrected it above, samsung said 2 times max, I’m not sure about other leds. I’m also sure the folks here have probably desoldered and reflowed the same led a ton of times and it’s probably fine. Yea, more solder paste for the new MCPCB.
Safer to just shave 2mm around the edge.
That was too easy, I used wire solder cuz I did not have any paste around, but it worked
There may be a problem with this, both anode and cathode tracks may get in contact with the MCPCB plate. A multimeter/ohmmeter for testing, plus a razor blade and careful handy work can fix the problem if it arises. The MCPCB rim will thank a tiny dab of glue to prevent the tracks from making contact with the MCPCB again.
Advice.-
Get a bunch of cheap emitters plus boards for DIY reflow practice. There are plenty of related videos lying around.
When reflowing control the temperature tightly. For example I use an induction stove plus infrared thermometer, allows nice ramp-up temperature control. Once led emitters are properly placed on the board(s) I shut-off the stove and the stove plus pan latent heat is enough for a slow and careful temperature ramp-down (cooling). When the stuff is in the ramp-down phase, well below solder melting temperature but still above 100°C I usually use some drops of alcohol based rosin flux over the MCPCB surface, removes any possible oxidation, and any rosin excess is later removed with alcohol.
Wow thanks for the advice, I did put an ohm meter on it before hand, maybe I got lucky with this one
Congrats on the mod! Certainly a useful skill to have in your pocket if you are at all picky about your LEDs! 