this has been bugging me for a while now. im on maybe my fourth or fifth build and i still cant figure out why my motor pads on the ESC keep lifting when i try to reflow a joint. its not every time but its happened on two different ESCs now, one was a Tekko32 and one was a random 4in1 i was using for a beater quad.

im using a hakko soldering station, temp is around 380c, 63/37 rosin core solder. i tin the pads first, tin the wire, then try to join them. the joint looks cold sometimes so i try to reflow it and thats usually when the pad lifts. ive watched like ten videos on this and i think im doing it right but clearly something is off.

is it the iron tip? its probably due for a replacement. or am i holding the iron on too long? the pads on 4in1 ESCs seem way more fragile than anything else i solder

tip condition is huge and yeah if its due for a replacement that might be part of it ? an oxidized tip transfers heat really inefficiently so you end up dwelling on the pad way longer than you need to trying to get the solder to flow, and thats exactly when pads lift. get a new tip, keep it tinned constantly while you work, wipe it on a brass wool tip cleaner not a wet sponge (thermal shock is real even if its subtle).

also 380 might actually be a little low depending on your setup. sounds counterintuitive but if your iron isnt transferring heat fast enough you compensate by staying on the pad longer. some people run 400-420 on motor pads and get in and out in like 2 seconds clean. quick and hot is usually safer than slow and moderate for this kind of work.

the 4in1 pads being fragile is just a reality unfortunately, some manufacturers are stingy with the copper layer thickness. once a pad lifts its kind of a pain to salvage but you can sometimes run a thin wire to a via if you're careful.

are you using flux separately or just relying on the flux in the rosin core? because adding a little extra liquid flux before you reflow makes a massive difference, the solder wets so much faster and you're not sitting there waiting for it. changed everything for me when i started doing that. i use the amtech stuff but honestly any decent no-clean flux works.

also just curious what gauge wire are you running to the motors? heavier gauge needs more heat to get up to temp and if the wire is pulling heat away from a small pad thats a recipe for exactly what you're describing