Re: sealing a cardboard tube?

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

Original poster: "Resonance Research Corp. by way of Terry Fritz <teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>


You can fashion your endplates out of standard 3/4 particle board.  After
carefully cutting the correct circle size tap it into the end for a flush
fit.  Then carefully drill and tap 1/4-20 holes into the wood by drilling
through the sonotube and into the wood.  I know, wood doesn't tap the best,
but it will work out ok for this application.  Don't tighten too hard or you
will easily strip out the threads.

Tap 8 holes at equal spacings around the 360 degree circle.

Use standard 1 inch long x 1/4-20 nylon (plastic supplier or plastic fab
house) bolts and place one in each of the eight holes.  Now you have a nice
endplate for each end of the coil.

Also, be sure to use RTV silicone to place a circular acrylic disk approx
6-7 inches top from the top end.  Silicone in place.  This prevents any
internal breakdown.

Now, you can remove the end disk any time you wish to make wire attachments,
etc.  Be sure to carefully mark the sonotube and disk with a magic marker
for an alignment mark so reassembly is fast and easy.

Use GE Glyptal for sealing the sonotube --- 3 coats inside and outside.
Glyptal available at any local electric motor rewind shop --- usually
available by the qt. size.

Dr. Resonance

Resonance Research Corp.
E11870 Shadylane Rd.
Baraboo,  WI  53913


--- snip ---

 > 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?