Re: Cigar secondary coil form (fwd)

---------- Forwarded message ----------
Date: Thu, 30 Apr 1998 10:59:25 +1200
From: Malcolm Watts <MALCOLM-at-directorate.wnp.ac.nz>
To: Tesla List <tesla-at-pupman-dot-com>
Subject: Re: Cigar secondary coil form (fwd)

Hi Alfred, all,

> Date: Wed, 29 Apr 1998 03:11:11 +0500
> From: "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
> To: Tesla List <tesla-at-pupman-dot-com>
> Subject: Re: Cigar secondary coil form (fwd)
> On Tue, 28 Apr 1998 21:17:25 -0500 RODERICK MAXWELL
> <tank-at-magnolia-dot-net> wrote;
> > I have been looking far and wide for a polystyrene coil form larger
> > than 4" in diameter but I never found one. So I decided to make one of
> > my own!...
> Making your own tube for a secondary form is a very viable option. I have 
> made large diameter plexiglass tubes like 2 feet in diameter by heating a 
> 1/4 inch thick sheet and then bending it into tube shape and then joining 
> the seam with methylene chloride. It's sure a lot cheaper buying the sheet 
> than an already formed tube! It's a shame it can't practicaly be done with 
> very low loss material like polyethylene or teflon, but damn near nothing 
> will work as an adhesive for these!

It can be done with PE. I used a 3mm thick wrap for my 17" skeletal 
former to help stop the ribs bending under the strain of the wire.
After *carefully* measuring the circumference I cut the sheeting and
"spot welded" it along the seam in several places. I then ran the 
glue gun slowly from one end to the other, melting the sheeting at 
the seam as I ran more hot melt rod in as a filler. It is helpful to 
have a shape to wrap the sheeting around. Other wise, it is very 
important that the seam be held absolutely end to end with no 
curvature until the melt sets fast or you can end up with a teardrop 
shape. The seam is a bit more flexible than the sheeting.
    BTW, a quick tip for using hot melt - you can use a can of 
"instant freeze" to help cool the outer portions quickly.