Phil Hobbs wrote:
Robert Baer wrote:
Phil Hobbs wrote:
William Sommerwerck wrote:
"Phil wrote in message
m...
William Sommerwerck wrote:
Wouldn't it be possible to make the polyimide conductive by rubbing
graphite into its surface ("The Audio Amateur" had at least one
article
about home-made electrostatic speakers that showed how to do this
with Mylar), then plate it?
I'd be worried about the film adhesion--the nickel would only stick as
well as the graphite. Plating plastic involves stuff like chromic acid
dips, reducing palladium salts to form Pd nucleation sites on the film,
and then electroless plating.
Not your ideal home project unfortunately!
Thanks for the clarification.
This is the sort of problem you'd think would have been solved
decades ago.
The original SX-70 used copper-coated (plated?) polysulfone, which
was then
plated with nickel and chrome. The plating sticks to the plastic with a
tenacity that's almost unbelievable. You actually have to break the
plastic
before the plating comes loose.
Oh, it's been solved, all right--Minco advertises nickel film RTDs. I
tried to get them to make the films, but they either couldn't or
didn't want to, and I didn't want to have to deal with making
artwork--I'm going to pattern it with a Sharpie and some ferric
chloride. (Ferric chloride works well on thin sputtered nickel, so I'm
hoping the plated stuff doesn't have some weird passivation. I should
try it out on a bolt or something before I take the plunge. Of course
I can also electropolish it away in KOH solution.)
BTW the Minco rep is a good guy, who gave me a steer to somebody who
may be their supplier--I just haven't heard from them yet.
Anyway, if it works, I'll try licensing it to them. 
It should be
good for at least 100x reduction in thermal forcing for the down-hole
application I'm working on--sort of the thermal equivalent of a
Faraday shield.
Cheers
Phil Hobbs
Jut had a dumb idea..how about unrolling mylar or other plastic caps?
I don't think I could find a 6-inch long one to begin with....
Then my roll of metalized film from Sprague won't help you. It came
from their Orlando plant closing, about 20 years ago.
--
You can't fix stupid. You can't even put a band-aid on it, because it's
Teflon coated.