Re: Sonotube (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- 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.
http://tesladownunder.com/Tesla_coil_18inch.htm#Secondary%20former
I suspect a PVC tube with greater thickness would be difficult to lift 
yourself.

Peter

----- Original Message ----- 
From: "Tesla list" <tesla@xxxxxxxxxx>
To: <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 
> an
> 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 
> is
> for ducting but runs >$30/ft for 20". Fiberglass, while ideal, is much 
> more,
> and way more heavy to transport (of course > mile of #12 or #10 awg will 
> be
> where the weight is)!
>
> So the question is how to coat the tube and how to baffle it. I am 
> thinking
> of bringing the coil form out near Las Vegas and let it set a couple of 
> days
> 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 
> disks
> would be screwed in place with countersunk flat head nylon screws with 
> epoxy
> 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 
> to
> go?
>
> Thinking down the road...
>
> Thanks
> Jim Mora
>
>
>
>
>
>