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[Closed] Hotend cleaning and other hotend questions  

New Member
Hotend cleaning and other hotend questions

I had a couple of failed prints, and got a bunch of PLA melted on and around the hotend. Took the whole extruder assembly apart and got most of it cleaned up. What I have left is mostly a thin coating over the entire end (see pic). I've removed heating element, sensor, nylon guide, and the plastic piece that holds the nylon in place. Question is, can I dunk the end in some acetone, and let it soak to clean it up. Will that work? I've heard that acetone does not work as well on PLA, will a few days soaking do the trick, or will that damage the hotend?

Second question. When I was removing the sensor, I noticed it was very loose, just sitting in there. I also noticed what I believe to be a threaded hole(hard to tell covered in PLA). Is there supposed to be something in there to hold the sensor in place? If so what size?

Last question. Is it worth while to change to a hard nozzle? I'm printing 90% PLA 10% ABS. Only ask because now would be the time to change it.


Posted : 20/03/2018 12:45 am
Martin Wolfe
Reputable Member
Re: Hotend cleaning and other hotend questions

The easiest way to get the remains of is to reassemble the hotend into the printer leaving off the print fan nozzle. Then heat the hotend to PLA temperatures. Once it is hot with a piece of kitchen towel taking care not to burn yourself wipe the remaining PLA of as it will now be soft.

Once it is as clean as you can get it that way it will be fine and you can put the print fan nozzle back on and recalibrate your Z adjust as disassembling and reassembling the hotend will cause it to change slightly.

With regards 90% PLA and 10% ABS no nozzle change is needed.



Martin Wolfe

Posted : 20/03/2018 2:02 am
atomleef liked
Re: Hotend cleaning and other hotend questions

pla does not dissolve in acetone.

acetone may discolour the aluminium of the heat block, but otherwise it will do no harm

there should be a grub screw retaining the thermistor. they have been known to fall out

your best bet is to get a brass brush, heat the heat block and brush the softened plastic off

as your heat break, cold end, heater block and nozzle are still assembled you can hold onto the round heat sink. and hold the heaterblock over a gas cooker, hot air blower or gas lighter to soften the plastic, then use the brass brush to rub the grot off

this way you don't damage the thermistor wires

Good luck

I try to make safe suggestions,You should understand the context and ensure you are happy that they are safe before attempting to apply my suggestions, what you do, is YOUR responsibility. Location Halifax UK

Posted : 20/03/2018 2:08 am
atomleef liked
New Member
Re: Hotend cleaning and other hotend questions

You can also try heating to 100C, where PLA starts to soften, but does not yet get very sticky... possibly then you can peel off larger strips or pieces cleanly. After removing a lot of material this way, then try heating to 215C and wipe remaining material off.

Posted : 18/01/2019 8:32 pm
Estimable Member
RE: Hotend cleaning and other hotend questions


thank you 🙂

Posted : 04/06/2020 4:04 am