> From: Esondrmn-at-aol-dot-com
 > To: richard.quick-at-slug-dot-org
 > Subject: Oil for capacitors

 ES> I am having trouble finding mineral oil in less than 55 gals.  
 ES> If I do find some, do I want regular food grade mineral oil?  
 ES> About 9 or 10 viscosity I think.  If I can get a couple of 
 ES> gallons of transformer oil from a transformer shop is that better?
 ES> Thanks, Ed Sonderman

I have always used Mineral Oil in my "production" capacitors, although 
I have had excellent reports from those who use transformer oil, and 
my recent experiments with silicone based fluids show promise.

USP mineral oil is available in the 'states' from any grocery store 
(in pints) or pharmacy (pints and quarts). My local Walgreens stocks 
quart bottles of USP mineral oil (laxative section) priced at $5.00. 
One gallon (four quarts) runs about $20.00. I have one capacitor that 
is filled with Johnson & Johnson "Baby Oil" which is simply a scented 
mineral oil that I bought on a tremendous sale at Walmart for $1.79 a 

The silicone oil I am using is a hydraulic fluid that is glycol and 
petroleum free. This is available in auto parts stores as brake fluid,
but tends to be as expensive, or a little more expensive, than the USP 
grade of mineral oil.

The viscosity of the oil is not critical, and transformer oils are light.
The oil used in my commercial pole pigs is about the same viscosity as
kerosene or diesel. In plastic capacitor construction the oil is simply 
displacing air in the capacitor, supressing corona and vibration, and 
distributing a tiny bit of heat. The primary function of the oil is not 
that of a dielectric.

Hope this helps.

Richard Quick

... If all else fails... Throw another megavolt across it!
___ Blue Wave/QWK v2.12