Welcome! Log In Create A New Profile


Have I damaged my hot end ?

Posted by joedassin 
Have I damaged my hot end ?
July 08, 2019 07:48AM
Hello all,

After several years of good services, the wades block of my mendel90 broke.

I got a new one printed by a friend of mine, and started the replacement operation.

When I disassembled the extruder assembly, I noticed that some material had flowed along the hot end. I thought it was PLA that had flowed during a failed print, so I heated it to remove it softly. I understood it was not PLA when it suddenly broke instead of flowing.

So I am wondering what it is. Could it be the car exhaust patty that Nophead is mentionning in the documentation, and which is use as a cement for the resistor and the thermistor ?

That leads me to several other questions :
> what could have caused this ? (I recently started to print a soft PLA which require a printing temperature of 200°C. Is it too much for that hot end ?)
> have I damaged my hot end ? if yes, how can I fix it ?


Re: Have I damaged my hot end ?
July 08, 2019 01:11PM
Perhaps it is PLA that has leaked and then cooked for a long time. Without a picture I am just guessing.

The exhaust putty is like grey cement. It is rock hard once cured and there shouldn't be any excess. It is only around the resistor and the thermistor.

I use those hot ends at 255C for ABS, so 200C is no problem at all. If the hot end is not starting to separate at the join but leaking just a little I would heat it up and then tighten the grub screw at the input end to push the PTFE liner down. If that doesn't work I would unscrew the brass part while hot and replace the PTFE tape that seals the join.

Re: Have I damaged my hot end ?
July 13, 2019 04:15AM
Hi Chris,

thanks a lot for your feedback, it is very reassuring. I re-assembled everything, and everything seems to work fine after a couple of prints.

Thanks again !

Sorry, only registered users may post in this forum.

Click here to login