Oozing silicone socks

I experience the silicone sock to ooze out hard, clearish drops onto the print bed from time to time.
When I removed the sock today, it was britle and hardened with cracks and a molten part.
Happened with an original micro swiss silicone sock.

Has anyone else experienced this and has eventually a fix against it?

Are you certain you don’t have filament oozing out of the joint between the heater block and the tube that joins the heater block to the heat sink above?

No filament leak, it comes from the silicone sock itself.
It is a quite clear substance that hardens to a glass like substance.
The sock itself has lost substance
I am thinking about replacing the sock with some aerogel sheet.

That is a silicone sock for sure?? How hot is the hotend? I have to think it’s a defective sock. Silicone rubber isn’t supposed to melt until it reaches 1400C.

Agreed, there is something else going on. Leaking plastic or maybe bad kapton tape (Edit: I’ve seen some cheap stuff from China that was like asbestos with a yellowish clear plastic tape on the outside).


It is a genuine micro swiss sock and I printed only PLA, mostly at 190°C, max. 220C.
Took some time until I realised it came from the silicone sock.
Maybe it was a monday piece, I’ll try it first with a new sock.

I was thinking about that, too.
I replaced the temp sensor the other day and the kapton was ok, I replaced it with a piece of 3M high temp silicone tape.

There are different types of silicone (mixtures). As the blue color.

Well, I guess I will find out about Micro Swiss blue socks very soon, since I just installed a Micro Swiss direct drive extruder on my Ender 5.

Hopefully this is it. You could print using the hotend without a sock (after a PID tune) as a visual check for problems. Regardless, Micro Swiss makes quality hotends. Let us know the solution!


P.S. – I see you replaced the thermistor before the problem. Any chance the thermal paste used could be part of the problem?!

While silicone socks are good as an insulator and protector for the heat block, I believe they are considered a wear item by the manufacturers that use them. There are many online listings for 3d printing silicone socks on amazon, ebay, and even walmart. I think the repeated heating and cooling of the sock causes them to eventually deteriorate such as shown by Erik.

This reminds me of the old saying “nothing lasts forever”.

How long should they last? Any advantages to WAHHING 10PCS 2mm thick Heater block cotton Safe Working Temp less 300°C For 3D printer Hotend https://amazon.com/gp/product/B01LAYCRAA/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

That’s a good question and why I find the OP’s issue is puzzling. Outside of accidents, I cannot imagine needing to ever replace one. But, because they are so inexpensive, I keep a few spares on hand. I think any thickness can work provided there is clearance for it (especially between the sock and the print bed). My spares are OEM equivalents so I don’t need to PID tune if I’m in a hurry, fwiw.


In a year and a half, I have not had to replace any of mine.