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High temperature thin dielectric or insulating coatings for bare copper coils?

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magicsmoke:
I need to build an insulation layer on some bare copper coil turns. Something like a Kapton tape would work great but the gap between the coils is very small and it would be very difficult if not impossible to get the tape layer between the turns and wrap around it. A polyimide, or polyester-amide coating like that used in high temperature inverter grade magnet wire would be ideal but I am not sure how feasible or safe it is to apply in a homework shop.

Some of the properties that I need are:
- The copper will reach ~200 deg. C for extended periods of time (essentially continuous)
- Ideally can tolerate high voltages (+600 V, depending on thickness of the insulation)
- Can wick or be drawn into small gaps (< 0.005” or <0.012 mm) and only leave a thin film coating
- Fairly chemically resist especially to oils
- Reasonable heat transfer coefficients to try to get heat out of the coils
- Safe to apply or use in a home work shop with just a basic organic vapor respirator and latex gloves

It does look like the polymer precusors for polyimide resins can maybe be purchased (this might be only in huge quanities). Has anyone applied a polyimide resin? Is it safe in this context?

Any recommendations of coatings, sprays or other chemical processes to use? I found a few papers where polyimide impregnation was used to insulate coils in particle colliders but there aren't many details to the process.

daqq:
I don't suppose you could rewind it from teflon clad cable? That would solve the isolation as well.
https://www.daburn.com/ptfe-wire-2.aspx

As to anything else, well, those are some fairly nasty requirements. Maybe submerge it into oil as a whole and then put it into something?

jonpaul:
Bonjour

The wire size?

Application eg heater of fluids?

Flammable liquid?

If you can replace the bare wire with properly insulated magnet wire use HPTZ or other triple insulated wire, available from Belden or Electrosol.

Expect 10...100# minimum order and special orders

Bon Chance

Jon

trobbins:
Is the copper coil made from a wire?  Is the wire circular?  What gauge wire? Is the 600V rating related to turn-to-turn withstand, or layer to layer, or ?  Is there a hot-spot situation in the coil (eg. due to multiple layers)?

magicsmoke:

--- Quote from: jonpaul on February 09, 2020, 09:42:45 am ---The wire size?

--- End quote ---

I haven't finished designing the coil but the wire size will be ~1.5 cm by ~2.5 cm in a non-uniform shape


--- Quote from: jonpaul on February 09, 2020, 09:42:45 am ---Application eg heater of fluids?

--- End quote ---

This is going into a motor so the coil will fit around a segmented tooth


--- Quote from: jonpaul on February 09, 2020, 09:42:45 am ---Flammable liquid?

--- End quote ---

The most likely coolant is sprayed automatic transmission fluid (ATF) or ATF flowed through a intersitial channel in the coil


--- Quote from: jonpaul on February 09, 2020, 09:42:45 am ---If you can replace the bare wire with properly insulated magnet wire use HPTZ or other triple insulated wire, available from Belden or Electrosol.

--- End quote ---

I am specifically not trying to use magnet wire so I can have non-uniform profiles of the conductor but I have't figured out yet how to do the insulative coating.

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