Poly surprise

From: 	baumann-at-proton.llumc.edu[SMTP:baumann-at-proton.llumc.edu]
Reply To: 	baumann-at-proton.llumc.edu
Sent: 	Monday, December 08, 1997 4:58 AM
To: 	tesla-2-at-emachine-dot-com; tesla-at-pupman-dot-com
Subject: 	Poly surprise

This is a heads up, for all those that are building poly caps. I got 
a nasty little surprise this weekend. I had built a flat-plate cap,
0.006 mf, made from *lots* of sheets of 6 mil poly. 430+ to be more
precise. Because I wanted to ensure that the plates were as tight as
possible, I made tie-straps across the tops and sides of the plate.
Each individual cap was approximately 10x7x1.5".
[the plates are between slabs of 3/8" polycarb, you use what you have.]
I filled it with oil, and and put it away for a few days. when I pulled
it out, all of my tie-straps had been broken off.
Why? Because the poly apparenly absorbed some of the oil, and expanded.
Less than 5%, but for 10", that amounts to 1/2" exapansion, more than
enough to be a problem. I've reworked the tiedowns, but thought I would
warn others, as I have not seen this mentioned in any of the
documentaion for capacitor constrution.  I was using Diala-AX for the

I hope to fire this at full power by the weekend [currently firing
at about 40%, but not seeing the bubbles I was told to expect, could
I have all the air out already? I did fill it very slowly, so that
the oil was always rising via capillary action faster than the oil 
was coming in [ I used a siphon through IV line, it took 7 hours to 
siphon the 1 gallon, I did not plan it that way.. it just worked out
that way] no other way to fill it without a vacuum pump.

Michael Baumann  Optivus Technology Inc.|Loma Linda University Medical Center
San Bernardino, California. (909)799-8308 |Internet: baumann-at-llumc.edu