I'm currently printing a thing with black PLA and it might not be enough. Can I put black PETG in there when it runs out and continue like nothing happened? I'd adjust the nozzle temperature, of course.
You definitely can’t, they don’t really adhere to each other at all. Like even to the extent that you can actually use PETG as easily removable support material for PLA.
There’s a reason why PETG/PLA are used as interface materials for supports in multi-material printers. There’s no molecular bond and so the parts will snap off very easily.
It may “stick” but it will not be a molecularly interlocked layer. The transition layer will be extremely weak and may snap right off if you handle it at all.
I have tried it and it doesn’t work.
I’m not sure that would stick. Mind you I’ve never tried it.
From a quick Google search it looks like PLA will stick to PETG but they don’t bond well
It also doesn't with with PLA and ABS. Same issue, they won't stick together well.