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Re: Sonotube (fwd)
---------- Forwarded message ----------
Date: Wed, 6 Jun 2007 08:09:50 +0800
From: Peter Terren <pterren@xxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Sonotube (fwd)
My 18 inch secondary former was custom made of 3 mm (0.12 inch)
polypropylene sheet welded around end caps and one centre cap. This is light
(weighs 9 Kg, 20 lbs) and the polypropylene is a suitable plastic in regard
to dielectric losses. It measures 45 x 150 cm (18 by 59 inches) and cost
AUD$250 to be made up by my local plastics shop.
I suspect a PVC tube with greater thickness would be difficult to lift
----- Original Message -----
From: "Tesla list" <tesla@xxxxxxxxxx>
Sent: Tuesday, June 05, 2007 11:08 AM
Subject: Sonotube (fwd)
> ---------- Forwarded message ----------
> Date: Mon, 4 Jun 2007 15:39:51 -0700
> From: Jim Mora <jmora@xxxxxxxxxxx>
> To: 'Tesla list' <tesla@xxxxxxxxxx>
> Subject: Sonotube
> Hello All,
> I am going to bring up the old topic of sonotube coil forms. I have both
> 8" and a 12" thin wall PVC coated coils. I want to get up into the 24KVA
> league which I'm told needs to get into the 20"-24" diameter size.
> I can buy Sonotube 24" with a .25" wall thickness which has a waxy coating
> on the inside. Cost is only ~$8.00 a foot. The cheapest PVC I have found
> for ducting but runs >$30/ft for 20". Fiberglass, while ideal, is much
> and way more heavy to transport (of course > mile of #12 or #10 awg will
> where the weight is)!
> So the question is how to coat the tube and how to baffle it. I am
> of bringing the coil form out near Las Vegas and let it set a couple of
> in the dry desert heat, than coating the OUTSIDE with marine grade epoxy.
> I am thinking three .5"X 24" equi-distant polyethene or coated plywood
> would be screwed in place with countersunk flat head nylon screws with
> applied to the area on the exterior. An interior adhesive would be
> desirable. The tube length would be 10 feet.
> If anyone has experience making the interior adhere to anything, I would
> like to know about it. Perhaps a completely evaporative volatile solvent
> such as acetone could clean the inside... Or is the Sonotube not the way
> Thinking down the road...
> Jim Mora