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Re: Kerosene?

Transformer oil is flammable too... One of the biggest reasons they went to
Askarels (PCB) in the first place was that it was inert, good dieletric
properties, and nonflammable.  Particularly in Europe, where distribution
substations tend to be in closer proximity to dense residential areas,
there were some oil fires causing spectacular damage. (Hence the popularity
of SF6 Gas Insulated Switchgear (GIS) and air blast circuit breakers. cf.
"Circuit Breakers", Scientific American, Jan 1970 issue (I think)).

Neither of them will burn if its all liquid and there isn't any air, even
if there is a spark.  In fact, oil circuit breakers use the decomposition
products of the oil (mostly hydrogen gas) to blow out the arc. It is true
that kerosine has a lower flash point than transformer oil, but it's still
pretty high.  I dare you to light a bucket full of kerosine on fire with
just a match and no wick or preheating. It's hard enough with a kerosine
camp stove.

If you were interested in a nonflammable dielectric liquid, you could use a
PCB that has been carefully cleansed of the toxic dioxins (It's the
contaminants that are the problem, not the PCB itself), or a silicone oil
(most of which are non-flammable) such as one of the Fluorinerts (but,
OTOH, they run $100/gallon).

I also noticed that most oils run about the same price per gallon,
regardless of their molecular length, in large quantities (about
$3/gallon). Drums of kerosine cost about the same as drums of Diala AX. 
Really, only gasoline is notably cheaper (in the US) due to the large
production volume. (Untaxed raw gasoline  (white gas/petroleum naptha) is
about $.50/gallon in tanker lots) and economies of scale.  I suspect the
same would be true in Europe for the pre-tax price, but the VAT system
makes it a bit tougher to figure out.

Actually, while researching some largish volumes of a variety of liquids
for a former employer, I discovered that almost everything in a tanker
(>1000 gallon lots) costs about $2-4/gallon... Sulfuric Acid, Ethylene
Glycol, Corn Syrup, Methanol, White USP Mineral Oil... The manufacturing
and transportation costs dominate the cost of the raw materials.

This has important implications for those people still using mineral oil as
an insulator to make capacitors (instead of MMCs).  Find a bunch of
co-oleophiles and do a group buy.  If you are in the Los Angeles area, I
can point you to sources.


> Original Poster: Megavolt121-at-aol-dot-com 
> 
> Jim, all-
>     Wouldn't it not be a good idea to use kerosene(or anything flammable)
to 
> "soak" your capacitors or transformers w/? I mean if you do get one spark

> from a short or burn through wouldn't you just create a big fire/mini
bomb?
> -Alan