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Registered Member #538
Joined: Sun Feb 18 2007, 08:33PM
Location: Finland
Posts: 181
Does anyone know if black PLA filament for 3D printing is prohibitively conductive for HV stuff? Already printing a small class-E tesla secondary former and started wondering... :)
Registered Member #2099
Joined: Wed Apr 29 2009, 12:22AM
Location: Los Altos, California
Posts: 1714
How about comparing black filament with other colors as a TC breakout point, or the tip of a grounded wand?
Blackness does not imply any more conductivity, or less dielectric strength, than natural resin or other colors. Even if the pigment is carbon black. Electrical tape for insulating HV utility splices is black. Most insulation on utility wires is black. G-10 fiberglass laminate is available in black. In all of those cases, I bet black is second to none when it comes to tolerating solar UV exposure.
Registered Member #2989
Joined: Sun Jul 11 2010, 12:01AM
Location: UK
Posts: 94
Throw it in a microwave oven, does it get hot? (you may need a small cup of water in there) but you could test say clear plastic and black stuff at the same time see if one gets hotter than the other. I think I have read about this method used by radio ham's to check if a coil former is any good.
Registered Member #834
Joined: Tue Jun 12 2007, 10:57PM
Location: Brazil
Posts: 644
I have used one that had about 10 kohms/cm, measured at the filament. I used it to make a high-voltage variable capacitor that worked well. A 150 pF capacitor ended with 15 kohms of series resistance, or a time constant of 2.25 us. Useful as capacitor up to 70 kHz. Enough insulation for ~800 V. Actually, it was ABS filament. In this case I was interested in the conductivity. Normal ABS is an excellent insulator. I am not sure about PLA.
Registered Member #538
Joined: Sun Feb 18 2007, 08:33PM
Location: Finland
Posts: 181
I didn't have any HV sources at hand, just arcing to it with one was my initial idea. I've tried measuring the resistance with my Agilent 34401A DMM which goes up to 100 MOhms and get nothing. I also heard a tip of using a higher measurement voltage such as main (230 V) and couldn't see _any_ leakage at that voltage either even with a very small amount of plastic. So I think it should be ok.
Would have wound the secondary already but managed to wind a bit and then ran in to a splice in the wire (0.6mm diameter Kynar wire), gah!
Registered Member #57929
Joined: Thu Nov 12 2015, 03:29PM
Location:
Posts: 5
I haven't had any luck using black filled "anything" for voltages above about 10KV. I have used bleck noryl (as a bobbin it ate through to the core), black eboxy (flashed between my windings). As a rule I use unfilled materials (meaning no carbon black additives).
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Black PLA filament conductivity?
