[ARC5] Coils and the winding thereof

[Michael Tauson]

On Wed, Jul 1, 2009 at 6:22 AM, Kenneth G.
Gordon<kgordon2006 at verizon.net> wrote:
> In the small transmitter you are thinking of building, several
> layers (for strength) of varnished paper, or those cardboard
> cylinders inside toilet-paper rolls (varnished) make perfectly
> good coil forms.

The first one is how the discussion started and the second ... well, I
know about that and the center tube for paper towels but they're kind
of obvious.  (Also, I've learned that some people get weird about
mentioning toilet paper roll tubes, though I don't know why.)

> Although they are somewhat "delicate", there is so little actual
> material there that the resulting coils are almost "air wound".

The build up varnished newsprint rolls my mentor taught me how to make
weren't going to even make a good wheel chock for an old Tonka truck
(Anyone still have an all-metal one or know where one is?) but they
held their shape well enough to wind coils on.  Sometimes it was
better to leave the coil form on whatever it was made on in the first
place until after the windings were added and the varnish (or shellac
in his case) was dry.

> You could also simply use stiff, solid wire, like #12 or #10, wind
> the coil on a dowel, then take it off the dowel and use it "air wound".

For some coils, that's how they'll be made, though I'll use a size
appropriate form and support a la the 1936 HB and other period pubs.
Some of the coils use wire too small to handle this way so they go on
forms.

> If you want a plug-in coil, use an old tube-base with the toilet-
> paper cylinder glued to it....or wind your own cylinder out of
> several layers of varnished stiff paper around the chosen tube
> base.

Part of the incoming package is UX tube bases.  :-)

> Certain sizes of PVC tubing fit tightly around certain tube-bases,

While not period available, like the Fiberglas mentioned elsewhere I'm
weakening on this if I can make it look period appropriate.

> The purpose of boiling wooden coil formers in parafin was to 1)
> drive as much moisture out of the wood as possible, and 2)
> subsquently prevent the wood from picking up moisture from
> the air.

Ahhh, I never knew that.  Thanks!

> I never felt the need for it, but did varnish the wood when I used
> that material.

I've always like spar varnish - the original as-used-on-wooden-spars
kind of spar varnish - since it's tough and waterproof.  My friend was
a believer in shellac and used it for about everything.  Another
gentleman I knew used clear butyrate aircraft dope since he worked in
a hanger and had a good supply of it.  (Funny how he always had kind
of a glazed look when he worked on something.  ;-) )  I guess it's all
in what one is used to.

BEst regards,

Michael, WH7HG
-- 
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Hiki Nô!