Notifications
Clear all

Mini Hotend question  

  RSS
Dragon1291
(@dragon1291)
Trusted Member
Mini Hotend question

Hello All,

Thinking of perhaps picking up a Mini Kit over the Summer (once the lead time isn't... ya know 3-4 months) however, I have yet to find any info on the Prusa website on if the Mini Hotend is All Metal or PTFE Lined.

From what I have read and seen it sounds like it is a PTFE lined hotend to at least some extent, which makes me a bit hesitant to purchase since I have two rowdy birds in my place of residence. Printers are in another room but would prefer to take no chances with a PTFE hotend of any sort. 

Attached are Birb pics because why not. 

Posted : 09/02/2021 2:44 pm
Turro75
(@turro75)
Estimable Member
RE: Mini Hotend question

lovely birds!!

mini hotend is ptfe till the heatblock so perfectly safe with PLA.

There is a bondtech alternative heatbreak which increases the distance of the ptfe from heatblock so it shouldn't reach more than 150deg with that setup.

Anyway some reported PLA quality issues. I have it and mine works perfectly.

Posted : 09/02/2021 3:29 pm
fuchsr
(@fuchsr)
Famed Member
RE: Mini Hotend question

I don't see an issue with the hotend but of course the Bowden tube might be an interesting landing place for your birds. If they go for plastic, you may have an issue. Of course, you can always put it in an enclosure. I have mine in the LACK v2 enclosures.

 
Posted : 09/02/2021 4:54 pm
Dragon1291
(@dragon1291)
Trusted Member
Topic starter answered:
RE: Mini Hotend question

@turro75 @fuchsr

Thanks for the info. I might end up going for the bondtech heatbreak just to be safe. 

Looking at the design drawings for the mini's heatbreak it looks like the PTFE liner ends right where the thread starts: https://github.com/prusa3d/Original-Prusa-MINI/blob/master/DOCUMENTATION/MECHANICAL%20PARTS/mini-heatbreak.pdf

If I were to run the Mini at higher temps than the normal 200-220 for PLA that I use, I definitely would not be comfortable with the PTFE tube being so close to the heat block. PETG and ABS would absolutely be out of the question until I got the Bondtech Heatbreak. 

In the MK3 there's 10mm of separation between the heatblock threads and the PTFE tube.  I wonder why they decided to essentially eliminate that in the Mini. 

Posted : 09/02/2021 5:46 pm
fuchsr
(@fuchsr)
Famed Member
RE: Mini Hotend question

@dragon1291

FWIW I’ve been printing PETG with the stock heat break for weeks, almost exclusively, no problems whatsoever.  I do have the Bondtech heat break but it’s sitting in a drawer. Why fix what ain’t broken?

Posted : 09/02/2021 6:03 pm
Dragon1291
(@dragon1291)
Trusted Member
Topic starter answered:
RE: Mini Hotend question

@fuchsr

Normally I would agree, but with the lives of my birds at risk, I'm not even going to chance it. PTFE can actually outgas at relatively low temps (210 or so) that while safe for humans is completely fatal for birds. 

Posted : 09/02/2021 6:08 pm
Share: