Re: varnish with guts ?

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

Original poster: "marc metlicka by way of Terry Fritz <twftesla-at-qwest-dot-net>" <mystuffs-at-orwell-dot-net>



Tesla list wrote:
> 
> Original poster: "Crow Leader by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<tesla-at-lists.symmetric-dot-net>
> 
> I have not tried this for what you want, but it may work.
> 
> I've noticed that a PVC pipe will shrink more in the cold than the copper
> windings. I wound some tubes and secured the wire at each end and let the
> whole coil get cold. The copper windings all slipped down and overlapped
> pretty much destroying the whole thing.
> 
> somehow freezing a pipe may get it to shrink enough to get the wire and
> varnish off it.


This is exactly right, you could use dry ice and a fan to blow the cold
air through it for a while. or just use a CO2 fire extinguisher and hit
it in short bursts to let each burst suck the heat out.
 Pvc has a pretty high rate of expansion in heat, I've seen small
extruded parts coming straight from the mold that are about three times
the size. You could do an experiment by cutting a short slice of the
coilform, OD it, then stick it in the fridge for a while, OD it again,
then stick it in the freeezer for a while, OD it. If you measure the
temp at room temp, fridge temp, and then freezer temp, you should get a
graph showing at what temp you need to shrink .001" for separation, then
if you cool the form so the windings are that temp, bataboom, you're
there.
 Keep us posted.
 Take care,
Marc M.


> 
> KEN
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Saturday, April 13, 2002 9:42 PM
> Subject: Re: varnish with guts ?
> 
> > Original poster: "PotLuck by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <potluck-at-xmission-dot-com>
> >
> > Hi Chris,
> > I dunno. I think even if something was found to hold the windings in place
> > then the windings would be so tight (tension of one wrap multiplied by
> 1000
> > or more) that it would be impossible to slide it off even with paper.
> >
> > However, if the coilform was built so it could collapse a bit without
> > sticking to the windings then there may be a chance.
> >
> > Rick W.
> >
> >
> > ----- Original Message -----
> > From: Tesla list <tesla-at-pupman-dot-com>
> > To: <tesla-at-pupman-dot-com>
> > Sent: Saturday, April 13, 2002 4:53 PM
> > Subject: varnish with guts ?
> >
> >
> > > Original poster: "Chris Swinson by way of Terry Fritz
> > <twftesla-at-qwest-dot-net>" <exxos-at-cps-games.co.uk>
> > >
> > > Hi all,
> > >
> > > I want to build a lot of coils but the pipe is costing me a small
> fortune.
> > > I was thinking that the varnish does a really good job of holding the
> wire
> > > in place. So I was thinking if I just got 1 length of tube and cover it
> in
> > > paper or something, then wind the coil on that. If there is something
> like
> > > vanish but maybe thicker or something that will keep the coil solid so I
> > can
> > > slide it off the pipe and the varnish stuff will keep it all solid. Thus
> > no
> > > need for the pipe then.  Something thick like paint but stronger would
> be
> > > ideal. Has anyone got any ideas for anything I could use to try this
> idea
> > > out ?
> > >
> > > Thanks,
> > > Chris
> > >
> > >
> > >
> > >
> >
> >
> >
> >