Re: sealing a cardboard tube?

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>

With my sonotubes, I use orange shellac which is also available at Home
Depot.  Orange shellac is better than polyurethane as it won't crack after
age like
polyurethane.  I usually put about 3 coats inside and outside of the
sonotube.  This advice was given to me by Ed Wingate as he uses sonotubes
frequently.

As for end caps, I used PVC Type I material I purchased from
www.mcmaster-dot-com  which were about $4.00 for a 12" x 12" x 0.5" plate.  I
cut to a disk and
glued top and bottom.  The bottom cap  I left rather large holes in to vent
fumes from the flammable solvent glues.  The top end cap is one you only
really need
to worry about to eliminate coilform internal arcing.

The following page has some pictures of my end caps etc... of a 10" sonotube
secondary i built.  Scroll to the bottom and there are close-up pictures of
the end caps.

http://www.spacecatlighting-dot-com/teslacoil7.htm


The Captain






 > I just got sonotube (cardboard tube) from homedepot that I will eventually
 > wind my secondary coil on. I know first, to wype it down with an acholed
 > (is that a word?) rag. But, to seal it, what should I use? Also, they sell
 > circles that are (.5" wide, not sure...) made of mdf. They don't have the
 > size I need (or course), so I was thinking it would not hurt anything to
 > have an inch or two hanging over the side. I could get my friend too cut
it
 > to the right size, but should I go trough the trouble? Could I use one of
 > these for the endcap for my secondary coil? And, would it be okay to use
 > metal screws to attach it to my sonotube?
 > Thanks
 > Adam
 >
 >
 >
 >
 >