Thing-O-Matic PTFE Replacement

Thing-O-Matic PTFE Replacement

GodfatherUr 12 Aug 2012 23:18

I have decided to upgrade my old TOM to the MK6+. I have delayed doing so as my bot was working ok, so I figure why upgrade when everything was working good, well printer started to show wear in the old heater block so I figured time to upgrade. I have just completed the upgrade and I realized that I accidentally cut the PTFE tube short by 15mm (I am sticking with 3mm stock for now as I have a lot left still). Is there anything that I can do to force the PTFE into the chamber further without damaging the tube? If not, is there a replacement that I can use as it appears as if makerbot no longer carries the PTFE for 3mm stock.

Thanks in advance

Re: Thing-O-Matic PTFE Replacement

Bluemetal 13 Aug 2012 13:59

Even if you force it down the tube, the pressure will push it back up again over time and create a bigger melting chamber that ultimately will produce burned ABS particles that can plug the nozzle (been there, done that and unfortunately have that T-shirt). :( http://wiki.makerbot.com/forum/t-374079/stepstruder-mk6-issues

You need to be sure that the PTFE is flush down to the inside of the nozzle. You may need to take the whole thing apart and use some persuasive force to get the tube all the way before screwing the nozzle onto the tube. Use the leftover PTFE tube (hopefully you have not thrown it away) at the top so it cannot crawl back up when in use.

I am not sure this helps. I am sure that McMasterCarr sell some of that tubing but I am not home to measure the outside diameter right now.

Last edited on 14 Aug 2012 12:53 by Bluemetal Show more

Re: Thing-O-Matic PTFE Replacement

Bluemetal 14 Aug 2012 12:52

The outside diameter is 1/4" and the inside is 1/8" (wall thickness 1/16").

The McMasterCarr (http://www.mcmaster.com) part (if you live in the US) is 8547K23 and it is good up to 260C. They sell a foot for USD 3.26+S/H.

I have not used it myself and I vaguely recall a discussion on the different PTFE alternatives in this forum but I could not find it. Like they say, your mileage may vary but it is an alternative.

Re: Thing-O-Matic PTFE Replacement

Jetguy 14 Aug 2012 13:09

Actually, he might be able to "get away" with it if he still has the piece he cut off. Just cut the tapered portion a little shorter (the flat top edge, not the taper) and butt up the waste peice inside the metal tube, then trim about 1mm above the metal tube. Since any melt is below the mid point in the metal tube (it's just there to prevent the old PTFE blowout or bulge problem), as long as the joint is above that, he's fine. With 3mm, it's all thick enough to never have a problem. No new tube required.

Last edited on 14 Aug 2012 16:27 by Jetguy Show more

Re: Thing-O-Matic PTFE Replacement

GodfatherUr 14 Aug 2012 15:27

Thank you all for the prompt replies. Here is what I ended up doing, I placed the PTFE tube in the freezer to shrink her up a bit again, disassembled the extruder assembly, and butted up the metal tube to the nozzle. I made sure the PTFE tube made it all the way down in the nozzle this time and placed the waste from the cut in the top portion of the metal tube. I will be completing the assembly tonight and testing her out. Anything else I should be aware of before I fire her up you think?

Re: Thing-O-Matic PTFE Replacement

Bluemetal 14 Aug 2012 15:50

You are good to go. Good thing you kept the other piece! :)