That kind of blob happens when there’s a leak between the heat break and nozzle. The faces of these two parts mate inside the heat block. Just screwing on the nozzle to get rid of the leak would affect the height of the nozzle above the print surface.
thanks, i will take a look for that, i had assumed it was the head catching the model and then the model stuck to the head and then it extruded into the model with nowhere to go, i don’t see any sign of leakage on later prints, but maybe something hardened to block the leak? do i just drop the hotend out, or do i have to disassemble everything to check?
Disassemble the hot end into the heater block, nozzle, and heat break.
Thoroughly clean, especially the threads. A threading tap can be used to chase the internal threads in the heat block.
Inspect the mating surfaces of the nozzle and heat break. Make sure they are flat and without nicks and gouges.
Reassembly the hot end with (a) the correct torque and (b) the correct gap between nozzle and heat block. There’s a thread here in the forum somewhere about the details.