Re: mdpe tubing for secondary form

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Scott Hanson by way of Terry Fritz <twftesla-at-qwest-dot-net>" <huil888-at-surfside-dot-net>

Justin -

Aside from securing the magnet wire to the form, your biggest problem may be
the very large coefficient of thermal expansion of polyethylene. If your
secondary will spend its life indoors at room temperature only, its probably
not an issue. If it will be exposed to either high or low temperatures, you
may find the windings sliding loose on the form, especially if they are not
somehow bonded to the form. If the form cools, it will shrink substantially
and the windings will slip. If it gets hot, it may stretch the wire as it
expands, and again your wire may end up loose after everything returns to
room temp.

Its certainly worth trying a PE form, but if you calculate the change in
diameter of an 8" form over a 40 degree F temperature range you'll see what
I mean.

Regards,
Scott Hanson
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Wednesday, October 23, 2002 7:40 PM
Subject: mdpe tubing for secondary form


> Original poster: "Justin Wright by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <justin-at-tracesofnut-dot-com>
>
> Hello All,
>
> I have found a source of MDPE tubing (thanks to Mark Finnis).  The
> tubing they have is 200mm (8") but the walls are 8-9mm thick.
>
> I have heard that the thickness of the tubing will affect the
> performance of the coil?
>
> Is this thickness going to be a problem?
>
>
>
> Regards
>
> Justin.
>
>
>
>
>
>
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>
>

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