PTFE safety

Hello,

I have but a bare minimum of electrical and mechanical knowledge and am considering building a RepRap. On the Thermoplast Extruder assembly page, it says that the parts made of PTFE may release deadly gases above 250 degrees. I get the impression from the page that the temperature is entirely controlled by the user via a computer. Still, given my limited experience, it is quite likely that I will make short circuits or even worse mistakes. Is there a risk that mistakes in assembly or usage can cause the extruder to get to this temperature? If so, what precautions can be taken?

Thank you for reading

Depends on whether you're talking about wrapping PTFE tape around the nichrome heating wire on the extruder barrel or if you are using PTFE for the thermal break between the extruder barrel and the polymer pump on the Mk II extruder. There's not much chance that you are going to go over the 300C you need to break down PTFE on the thermal break. The tape is another matter. Nobody I know tries to insulate the extruder barrel with PTFE tape any more. I use BBQ paint. Others use epoxies like J-B Weld instead.

Thank you so much for your tips on the tape. I will definitely do as you suggest.

Are there any precautions that could be taken for the thermal break? I understand that it may not be necessary, but it would be nice for piece of mind.

I redesigned the whole extruder because I knew I was going to be working with HDPE and HPP which are much higher temperature plastics.

[3dreplicators.com]

There is a link to the documentation about how to build my extruder barrel. You see it has a brass plate at the top which acts as a heat sink and radiator. I've never had the HDPE at the joint between the extruder barrel and the HDPE block that I use for a thermal break exceed 105-110C. Most times it runs about 80C.

[www.3dreplicators.com]

Here you can see how the whole jerry-rigged assembly fits together. Weird as that looks it works quite well. I could usually get 40-60 hours out of it before I had to do a maintenance breakdown.

Nophead has been working on a similar approach.

[hydraraptor.blogspot.com]

I'm not sure where he is with his at this point, though.