Formless Seconday


>I have just finished building a couple of scaled down versions of a tesla
 >coil secondary. I used a cardboard tube covered with a couple layers of
 >I am now pondering the attachment of the torroid and base.
 >I was thinking of epoxying something to the top and bottom. Instead of
 >cutting out a section of the bottom for gnd attachment, maybe incorporating
>something as I am coating. Still thinking on this. I also am considering
>maybe just running a 4 small dia acrylic rods inside the tube, epoxyed the
>length, from top to bottom.

When one buys a commercial air core inductor of large size, it's wound on 4
polyethylene ribs and melted into the outer edge of the plastic. This
contributes to a few degrees of arc filled with a "lossy" plastic instead of
the full 360 degrees. So, consider fewer layers of lacquere/epoxy and ribs
glued inside for support. This will reduce the disapative material volumn
and provide the strength you need for mounting and bumping.