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catastrophic failure  

Jerry S
Trusted Member
catastrophic failure

I have been printing for 6 weeks..............a newbie. But everything has been going great until today. I have a print failure and it looks so bad I do not know how to clear it without breaking something. Please help. Pictures attached/enclosed:



Posted : 06/10/2020 8:20 pm
Jerry S
Trusted Member
Topic starter answered:
RE: catastrophic failure

Just want to ad this to my post. This failure occured, my best guess, less than 30 minutes into a 6 hour print. I have done this print a half dozen times without a problem. Aside from info needed about how to clean the failure I would like to know why the failure did not show up sooner.

Posted : 06/10/2020 8:42 pm
Illustrious Member
RE: catastrophic failure


This usually happens due to poor first layer adhesion. Maybe this video helps you to remove the blob:

A heat gun may also be necessary for support. In any case you should work very carefully so that you do not destroy the wires of the thermistor and the heating cartridge.

Good luck!

Statt zu klagen, dass wir nicht alles haben, was wir wollen, sollten wir lieber dankbar sein, dass wir nicht alles bekommen, was wir verdienen....
Posted : 06/10/2020 9:32 pm
Noble Member
RE: catastrophic failure

Gerald, I hope you don't mind if I share your photo in the Blob Of Doom Gallery, which is on line here:[email protected]/pool/

If you  look at the photos, you'll see that there are quite a few worse than yours.

I've only had a minor one, which I caught shortly after the print broke away from the textured sheet and I walked in to find a blob on the nozzle and the extruder dragging the remains of the print around the build plate like someone trying in vain to walk a cat on a leash.  😉

In my case, I got it good and warm, let it sit for a while, and with only some gentle persuasion the blob dropped free.

What I have done, in case I do have a more serious blob that damages some of the extruder pieces is to print spares of them in advance.  I keep them in the 'crash kit' with spare belts and other goodies that it's better to have and not need than need and not have.

As was stated, if I were you, I would simply let the thing get very warm and, CAREFULLY - a little goes a long way, use a heat gun to soften the blob and GENTLY coax it loose.   It's hard to tell from your photo, but some thermistor and/or nozzle heater wiring may be involved, so please be VERY careful when you attempt to remove the blob and don't force anything!

Posted : 06/10/2020 9:43 pm
Illustrious Member
RE: catastrophic failure

These happen because the plastic adhesion fails - the part comes loose from the print sheet and - well - here you are. 

Once you get the blob off the extruder --- and as stated before be very careful with any procedures because the wires to the thermistor and heater are beyond fragile --- take some time to do a thorough cleaning of the print sheet. And watch for fingerprints and plastic residue that builds up over time and do diligence to inspect and deal with it before every print. 

Posted : 07/10/2020 12:23 am
David Witkowski
New Member
Clearing the PLA Blob of Doom

I just cleared a PLA Blob of Doom from my Mk3S+ - it had managed to get up around the heater and thermistor wires, into the fan duct - it looked like some kind of alien paw that was gripping the entire extruder assembly. I worked carefully around the blob, bending each side out until it started to come loose. At one point the system did a heater self-shutdown (safety feature) but no alert beeps so I had a moment of panic when I noticed the heater getting cooler.

I took advantage of this cooldown to cut the strands and pull the main mass away, then I went back to about 130 degC to do the detail work - that was a good tip from Dote and others, as the PLA is soft enough to move but firm enough to help peel some of the remaining PLA. Took about two hours including recalibration.

Silicone Socks are on order - arriving tomorrow!

Posted : 24/10/2021 8:24 pm
Active Member

Hi, complete noob here. I have heard tell of silicone socks, but don't understand the use case. How do they help mitigate this issue?

Posted : 29/10/2021 2:48 am

Hi Protium, 
Socks are a contentious issue.. 

Some folk love em, 
Others Hate em

I tried the 'Professional' silicone socks. bought a pack of three, fitted one and...

I lost one job, where the print came adrift, blocked the tiny hole, in the sock, and caused the filament to be directed up inside the sock, in intimate contact with the heater block, and around behind the heater block, making a worse mess than usual...

having cleaned the mess up, I put the sock back on,  and a while later, the thin layer of silicone covering the nozzle, hardened , split, and caused a crash.... 

so I have never used the other  two socks...

some folk find they fall off, so they use fuse wire to hold them in place. 
others say the socks that leave the nozzle exposed are wonderful...

best bet is to make up your own mind

Prusa choose not to include socks...  maybe they have a reason... 

regards Joan


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 : 29/10/2021 9:01 am