[time-nuts] Re: Source of small quantities of teflon insulated thermal wires for cavity heating?

[Michael Fahmie]

I've used fiberglass insulated thermocouple wire, the Constantin conductor
has plenty of resistance and the current can be fed back on the other
conductor to minimize inductance.
-Mike-


On Wed, Feb 7, 2024 at 5:40 AM Jim Lux via time-nuts <
time-nuts at lists.febo.com> wrote:

>
>
>
>
> I don't know that I've ever seen PTFE insulated resistance wire. 10-50
> meters is pretty long, so you probably can't do it by sliding a PTFE sleeve
> over the wire.
> I have seen references to wire that is 377 ohms/square in antenna testing,
> but I'm pretty sure that was "fabricated by the experimentalist" using
> something like "space cloth" (paper with a 377 ohm/square resistance).
>
> You could call or write a company like MWS (https://mwswire.com/). They
> do custom wire all the time in all sorts of weird configurations. They
> definitely have resistance wire (about 20 different kinds), and I know they
> do custom coatings (the data sheet says bare or insulated), but I don't
> know about PTFE.  They sell PTFE/Polyimide tubing from Elektrisola Medical
> Technologies.
>
> They definitely do small production runs (although it might be
> expensive).
>
> PTFE insulated wire in general is easy, so if you can find a company that
> does the "coating" they should be able to do a run with whatever wire you
> want.
>
> An interesting problem.  FWIW, a more common way to make heaters like this
> is to combine flat conductors with a substrate. Either evaporate it on with
> a mask, or coat a whole layer, then etch it. Adhering to PTFE is kind of a
> problem, but they could probably roll a flat sheet, lay the foil over the
> top, etch the right pattern, then lay another sheet, and thermally bond it
> as a unit. I'd think that something like polyimide (Kapton) would be more
> common.
>
>
> On Tue, 6 Feb 2024 15:01:43 +0000 (UTC), Ulf Kylenfall via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
> Dear time nuts.
> In need of teflon insulated kanthal or NiCr wire for cavity heating.
>
> Are there any known sources that can supply quantities in the order of
> 10-50 meters?
> Regards
> Ulf KylenfallOnsala, Sweden.
>
>
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