Original poster: "D&M's High Voltage, Inc." <dmshv.davmckin@xxxxxxxxxxx>
Gerry,
The taping (paper, masking tape, or even Aluminum foil tape - tried
that too but forgot to mention it) was to make a smooth surface to
start with (which also cuts down on weight) by eliminating having to
fill up the corrugations of the duct. It's well worth the time
spent. I would suggest covering the toroid first with one of
mentioned tapes, and then apply one (thin) layer of resin (hot or
not, just so it doesn't run). Sand the rough part down, then apply
another layer of resin. Sand the rough parts, then fill in the large
indentations with bondo, smoothing out as much as possible. Sand
them down. Then apply another layer of resin. Sand down the rough
parts, and then fill in the indentations with bondo. Apply another
layer of resin, etc. Keep repeating until you have a smooth surface
(should be a few layers and will require less with experience).
Using masking or aluminum foil tape will stiffen the toroid quite
nicely. Start sanding with large grit (I was limited to 60 Grit, but
30 if you can get it for your sander). Then when you get to the
last fiberglass layer / sanding operation, step down to get a smooth
surface without deep sanding swirls. I finished with 150 and 220
(final) paper. Make sure you use a vacuum system when sanding, or
do it outside! Use acetone to get a very clean surface so the tape
will stick really good.
Best regards,
David L. McKinnon
D&M's High Voltage, Inc.
----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Sunday, August 21, 2005 12:14 PM
Subject: Re: Toroid Building
Original poster: "Gerry Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
Hi Tim,
I will probably try either the bondo or the redevil "onetime"
product on this toroid. I will eventually make a 10x40 toroid
after I learn from this one. David from D&M suggested, I think,
paper taping the duct first (I presume to save weight), applying
the bondo, and then doing the fiberglass resin coatings for
strength. I'm thinking of applying the bondo and filling the
corrigations, sanding, varnishing, and then adding the AL tape. I
suppose, I will find out how heavy it becomes and alter the process
for the 10x40 toroid. Dont know how heavy bondo is compared to the
redevil product nor how much filling the corrigations will improve strength.
Gerry R
Original poster: Timjroche@xxxxxxx
Gerry R.,
have you tried bondo...easy working, stable, and cheap....or
even the fiberglass bondo for rigidity.....good luck... i'd like
to know what you do... i'll be doin te same in 2-3 weeks.....tim