Lynn wrote:
"Smokey" wrote in message
m...
Hello fellow glow worms...

Does anyone know of a source for very thin mica suitable for my rebuilding
trimmer pads? I've been using clear plastic but results have been
unremarkable and think if I am going to do this I should do it right.

I'm looking for some that might be arounf 0.003-inches in thickness +/- .

I'm sure this is not the best answer to the problem, but when I've
needed
a particular padder/trimmer rebuilt, I looked to other old padders/trimmers
for "new" micas. Often
the junkbox has old padders (higher capacity ones had lots of mica
dielectric sheets).
You can "make" smaller capacity trimmers by removing plates (and their
mica) from
larger capacity ones if other problems exist (like broken ceramic body)
But I'm pretty sure you may already know all this.

Old Chief Lynn.. W7LTQ


I too have repaired/ modified them by scrounging insulation and parts
from other trimmers. I have considered replacing some with Teflon. The
dielectric constant is not the same but you may be able to compensate
for this using thinner material. I have used PTFE in a couple of
screen bypass caps where the mica had broken and it worked well. I
actually got an increase in the amount of capacitance even though the
dielectric constant for teflon is less than mica. I have also tried
getting mica out of an old toaster, this didnt work as all the pieces
I found were so perforated as to make them useless.

Jimmie