PTFE Coated (Non-Stick) Nozzles - Do they work? 

Ohhh very interesting info, I'll have to check those 2 numbers

I use that option but small wire brushes soon get clogged. Ive seen a servo operated arm addon for the voron 0.1. That does automate this cleaning, its something ive been meaning to install

@@ThisDesignedThat I use a large one. The bristles tend to splay out over time (like an old toothbrush) but it still works. I didn't find out about wire brushes until I'd been printing for a couple years, and dirty nozzles were a huge annoyance as a result.

Mhm PTFE is external only, and the air is what maybe 40 50°C cold tops. So there's a gradient and PTFE is definitely much much colder than the nozzle set point. I have done some K-type thermocouple probing. With regulation setpoint of 250°C, i measure about 260°C at the heater cartridge, 215°C on the nozzle sides, and 190°C on the slant near the nozzle tip. Super clean new nozzle. No airflow. In contrast if you have PTFE liner, it will reach setpoint temperature. I think the inside of PTFE layer of the coating at the cone of the nozzle will be at least 20° colder, which should give you leeway to print engineering polymers which need a little above 250. I would remove the PTFE coating at the hex flats of the nozzle since it will be the hottest there and doesn't really contribute to printing, also prone to get scratched up.

@@SianaGearz i really doubt that the top is any colder than the middle of the nozzle. Maybe if it would be water cooled. Air is really bad in cooling stuff. It´s 1-5 °C diffrence at max if you ask me. Thas the whole idea why people use brass nozzles. Otherweise clogged nozzles would be a much bigger issue.

@@Gromic2k I don't think it would be. After all the plastic in the nozzle is molten, so as a liquid, it has a pretty high thermal conductivity itself. As a solid when it's cooled down, the thermal conductivity is low. It takes a good while when the hotend is already at the melting point of the plastic to actually re-melt the plug in the nozzle, but it's hidden by hot-end's settling time before the print begins. We also print a LOT hotter than the temperatures at which the plastic begins to be molten, about 50°C hotter typically. Thermal conductivity of brass is neither particularly low nor particularly high, and even twice as thermally conductive aluminium it's easy to measure a thermal gradient from the hot to cold ends of it in free air. You also have a thin wall structure at the conical section of the nozzle which is the one that matters for the coating. I think it's fair that a better experiment is needed to see what the temperature of PTFE coating in the working zone would be. I tried Kapton taping the thermocouple but wasn't very successful with the setup, it didn't want to stay put - Kapton would imitate the gradient over the thickness of PTFE.

as long as it dries properly and there's no risk of getting it on the build plate I'm sure it'll work. Yes you definitely don't want to get PTFE super hot so it starts to off gas

I'm sure it works similarly. Shame he didn't show any examples in his video

@@ThisDesignedThat PTFE doesn't seem safe to heat past 220C, teflon flu is also a thing, found this Molybdenum Disulphide interesting instead, has much higher temp resistance, comes in a dry spray

I tried that with some ever so slightly cheaper (£14 vs £17) "DM-90" brand and it didn't want to stick to the brand new brass nozzle and just wiped off. Maybe I should try again and leave it for 24 hours (even though it said "touch dry in 15 minutes").

@@KentoCommenT Very interested to know if it does stick after more drying, or maybe it depends of the brand of MoS2 dry spray ?

Glass transition temperature. Melting point temperature. Find a temp in between those two to peel off your plastic. Some plastics peel off below melting point without coating