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foam toroid update



all,
i want to give an update to the foam toroid i was making, i say was
because when you spray polyurethane finish on polyurethane foam, it
melts the foam, i should have realized this, go figure?
all the work of gluing the ring sections together, sanding the foam
until the edges mated to give a round form which came out perfect,
turned into a gloopy mess after one light spray, lol.
my next idea is to mix wood glue with water and paint on with a paint
brush or use the wagner to spray it into the voids, then after drying,
i'll sand and spray, sand and spray until smooth. i did spray a foam
ring toroid that i covered with box tape, with graphite spray lube,
sanded after dry with 400 grit sand paper, sprayed, sanded, and it came
out very smooth. i then sprayed with krylon copper paint and let dry.
i placed it on my test coil and fired it, it worked great, the only
thing is that for some reason there was many more streamers that danced
around allot? it could be that this was the first very smooth toroid
that i had used, i'm not sure. it's not that the streamers were shorter
by much, just many more, it also could be that the graphite did give a
resistance of about 15 meg in a space of about an inch so the resistance
is higher than foil tape?
the thing is that the graphite works on toroids too.
i'll keep all posted as soon as i get more foam and glue up another form
and try the wood glue for a sealer before spraying.
marc