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Re: tapered secondary form?

Tristan,

You may want to consider the following.

In view of the size of the coil, and the mass,
you may have flex or sag problems; particularly
if you contemplate ever moving the coil in a vehicle.

One possible solution that others have used is to
"glass" the outside of the form. I am not sure of the
epoxy-resin specs that need to be followed, but
maybe someone else knows off-hand, I think this
was discussed some time ago in the archives.

This would also "patch" the seam between the two
containers.

Another thought is the support of the coil.
The easiest way to mount the coil is to just rest it
on the end. A disadvantage is that you would have
to build up a base under either the primary or the
secondary to adjust the coupling constant. An
alternative would be to build a telescoping support
from two nested PVC pipes positioned with nylon
bolts. This mounts to the joined bases of the
containers, reinforcing the joint between them.
By this technique you solve several problem, but
it is definitely more work.

Bryan Kaufman

Tesla List wrote:

> Original Poster: "Mad Coiler" <tesla_coiler-at-hotmail-dot-com>
>
> Thank everyone for the feedback,
>
> I will most likely plan on using lots of nylon bolts and epoxy. For
> everyone who wasnt sure, my secondary (when the two pieces are
> assembled) would be 14" diameter by 54" tall. I am not sure but just the
> two pieces way about ~10 lbs, and that much magnet wire (probably #16 or
> #18) will most likely be 20-40 lbs - I am not sure, perhaps someone has
> the weight/length value of the wire? So if anyone doesnt think that this
> will be too heavy, I will go ahead with the glue and nylon bolts.
>
> Thanks,
> Tristan Stewart (KC2EBM)
>
> >Tristan,
> >You definitely do not want any metal inside your coil. I don't recall
> >the size of your buckets, but what worked for me was hot melt glue. I
> >put together a 6.5 inch secondary using plastic paint buckets (1
> >gallon). They are utra thin polyurethane, so I figured it be good for
> >low RF loss. I ground off the handle catches with a dremel, then used
> >the hot glue in between each of the five buckets, as glue oozed out, I
> >scraped it with wide blade screwdriver (while it was still hot). This
> >held very well, and I haven't had any problems with coil!
> >Hope this helps!
> >
> >P.S. (for you coilers with tight budgets, this is a cheap, quick form
> >for secondary - you can get them free from a painter or for a couple
> >bucks new.)
> >
> >Bob Volk
> >
> >
> >>
> >> Thanks, Bert, for the response. I was starting to think the same way.
> >> Putting the bases together may also make it easier to connect the two
> >> together. This brings up my next question, which is: any
> recomendations
> >> on how to affix the two halves together? I assume you dont want any
> >> metal of any sort in the center of the socndary? I also assume that
> >> judging the size of the coil it will most likely be heavy and epoxy
> >> alone may not be sufficient. Does any have any tricks they use?
> >
> >
>
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