Warning: Printing At High Temperatures May Create Harmful Off-Gassing
Safety Precautions
PTFE is a flouropolymer, which exists in a state of matter known as a "glass." This means it does not "melt," like an ice cube, but rather slowly gets softer and softer as it gets warmer. Eventually it will either become a liquid, or catch fire.
Between room temperature and catching fire, all polymers emit tiny amounts of harmful gasses, known as "off-gassing." The hotter they get, the more they will emit. See Chart*
Because our PTFE tends to have better temperature resistance (meaning it stays firmer at higher temperatures before significant deformation) than lower quality PTFE tubes, a number of users have reported success using it "inside the hot end."
This is not something you should do willy-nilly. Just because it works, doesn't mean there aren't precautions to be taken. If you use PTFE, or any polymer for that matter, inside the hot end or anywhere excessive temperatures may be experienced, you will potentially create harmful off-gassing. Not only that, but the polymer you are extruding may be creating harmful gasses as well.
We strongly recommend running your 3D printer in a well ventilated area, away from children and pets.
In a classroom environment, we encourage printing with PLA, and staying away from higher temperature materials, whether you use our Bowden tubing or not.
Always have adult supervision when operating a 3D printer.
Keep razor-sharp Bowden tubing cutters out of reach of children.
Have fun, and stay safe out there!
Safe Printing Temperatures
"Can I print X in my Y printer with your tubing?"
Your results will vary quite a bit due to the different designs of hotends and many other variables. But the bigger concern is safety, rather than whether it physically "will work." Small amounts of off gassing are harmless to humans, but dangerous to pet birds living in the house, for example.
In order to try and answer this, we've come up with this handy chart. This applies to situations where the PTFE is INSIDE the hot end, experiencing the full heat of the nozzle.
| Temp (Deg C) | Will it work? | Is it Safe? |
|---|---|---|
| 170 | YES | YES. This temperature is perfectly safe for printing PLA. |
| 180 | YES | YES. All good. |
| 190 | YES | YES. This is the within the optimal range for printing with PLA and even some ABS. |
| 200 | YES | YES. This temperature is perfectly safe for printing PLA. |
| 210 | YES | Mostly. There is evidence that even at 202, PTFE can be harmful to pet birds http://buffalobirdnerd.com/clients/8963/documents/Teflon.pdf |
| 225 | YES | YES. This is the ideal temperature range for most ABS. When printing ABS, the most danger comes from off-gassing and nanoparticles of the ABS itsself. https://www.dezeen.com/2016/02/16/health-study-reveals-harmful-toxic-effects-hazards-3d-printing-illinois-institute-technology/ |
| 250 | YES | YES. You should be fine printing slightly higher temp materials lsuch as PETG in this range. (As long as there are no pet birds in the house.) |
| 260 | YES | We do not recommend printing with our TL tubing above this range. Our XS Series tubing has additives that will allow it to print at higher temperatures without deforming, but safety is still a concern due to PTFE offgassing. |
| 270 | YES | Mostly. 270 is approximately the highest temperature at which we have had sustained successful printing over many hours/days/months with no issues. |
| 275 | YES | Maybe. At this temperature, PTFE off-gassing has been known to kill pet birds because their cardiovascular system is much more efficient at absorbing toxins than ours. http://www.peteducation.com/article.cfm?c=15&aid=2874 Printing high temperature materials should be done by experienced professionals only. It is still relatively safe to humans and other pets, but it is best to err on the side of caution and always print in a well ventilated area. |
| 280 | MAYBE | Maybe. At the 280-290 range, the tubing is likely to eventually deform during long prints. |
| 300 | Tube lifespan will be shortened | Maybe. This is entering the danger zone. Printing at these temps should only be attempted in a well ventilated area. PTFE may start to soften and fail physically after some time. Also, the filament you are printing with may be creating off-gassing as well. We recommend using XS series tubing only above this point, and running the printer in a well-ventilated area. |
| 340 | Tube lifespan will be very short | NO. At this temperature range, the PTFE will deform physically and may cause clogging. We know some people have had success at these temps but we can't promise it will work for any given set up. Printing at these temps should only be attempted in a well ventilated area. |
| 400+ | NO | NO. At this temperature range, off-gassing dangerous to humans will be created by both the filament and the PTFE tube, and the life of the tube will certainly be diminished. The authors of this paper performed their tests at 460 C https://www.fluoridealert.org/wp-content/pesticides/teflon.effects.lung.htm We do not recommend printing in this temperature range. |
Food Safety
PTFE by itsself is generally considered a food safe polymer. It is commonly used as a non-stick lining on frying pans.
PTFE Tubing, specifically, is often used in medical applications, because it does not react with bodily fluids.
That does not necessarily mean your Bowden tube is food safe, however. It is processed in an industrial facility without the types of cleanliness precautions, etc, that would be necessary to call it "food safe."
In the event, for example, your dog eats a piece of our tubing, we are not aware of anything in our additive blend that is particularly hamful. The bigger risk is the choking hazard. If an animal is unable to bite off the end of a tube, they may be unable to swallow it. Please keep this and all 3D printing products out of reach of small children and pets.