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This is a pretty embarrassing question. I just built my first printer -- a generic Chinese Cartesian kit -- and have been running through basic calibration and checks before initial printing. In the process, I ran the hotend and bed temps up a bit (not to operating temps) just to test the heaters and thermistors. All seems OK. But just as I was getting ready to set up for a printing test run, I noticed that the hotend above the nozzle appears to be wrapped in some sort of clear plastic (even apparently over the hex nut I assume is used to remove the nozzle itself). Two photos attached. My first inclination was just to assume that this was shipping protection, cut it, and remove that plastic entirely -- but then I aborted that out of concern that there might be some operational reason for that to be there of which I'm unaware. While it survived my minor heating tests I doubt it would survive at full operating temperature. So, should I remove it? Sorry to be asking what must be such a basic question, but I've been burned before (no pun intended) by making assumptions during my engineering career. Thanks very much!

That is Kapton tape, which is a high temp tape. It was put there for insulation - either for heat or electrical insulation. So leave it there.

Thanks! So glad I checked on this. So just punch through the tape to reach the hex screw if I need to remove the nozzle? Thanks again.

Yes or replace the Kapton. You can buy it by the roll in almost any width. Some folks print on it as a bed surface.

Thanks!

I think I see the thermistor entering the alu block just beside of the heatercartridges. So I think the tape is also used for fixing the thermistor. An E3D uses a screw for that (or have cartridges type of thermistors nowadays. Kapton id often used to insulate the heatblock or nozzle from too much airflow of a layerfan. I never pack my hotend in kapton because it becomes so sticky if you remove the kapton. But as said, my E3D uses a screw to fix the thermistor. Yours probably doesn't.

Generic Chinese 3dprinter forums are less helpful?

Thanks.