On 10 Aug 2003 08:19:18 -0700, (Art Unwin KB9MZ)
wrote:

Well it would seem that the 'don't use motor oil' comment
which has been passed on by mouth to mouth over the decades
doesn't seem to stand up to scruteny.
Yes, the question is raised so many times over the years
and the same old stories pop up, but without any
substantiation such that it just appears to be gossip.
One statement mentions attack on resisters, where's the proof,
If it is true then it surely can be easily overcome.
Hopefully this time, one of the many posters over the
years on this subject will make observations that are
relevant to the present day instead of waiting for a book.
Art


Well Art, the detergents in modern motor oils are specifically
formulated to dissolve carbon deposits and sludge (largely made up of
carbon) and keep in in suspension. I'm pretty sure that the resistor
in my Cantenna is carbon. Transformer oil is formulated to have a
high dieletric strength. Mineral oil is relatively pure, lightweight
petrolatum (like liquid Vaseline(r)) and has a pretty high dieletric
strength just because of low impurities. Motor oil? I don't know.
ATF? I don't know about that either. What I do know is that the
designers of my dummy load specify either transformer oil or mineral
oil. That's good enough for me. I'll mosey on down to the
transformer shop of the local electric utility and buy the folks there
a round of coffee in the morning or over to the veterinary supply and
buy a gallon of mineral oil U. S. P. I think it's safer that way. We
hams are in interestingly cheap lot. We'll spend thousands on a new
rig that could break down tomorrow and then pour a gallon of
"whatever" into the dummy load instead of spending twenty bucks for
mineral oil or fifty bucks for MFJs transformer oil. This in a unit
that with ordinary care will last a lifetime. Sheesh!

Russ








"Keyboard In The Wilderness" wrote in message news:4q8Za.31351$ff.14186@fed1read01...
From the Google Group Search Engine: For what it is worth

The Handbook (at least my 1990 edition) has some information on this
subject.
In the Station Accessories chapter there are plans to build a couple of
Cantenna type dummy loads. They mention an oil sold by Texaco (if I remember
correctly) for turbine lubrication that is, according to the author, the
same
oil as is used in transformers. They quote the exact product designation.
Apparently, it's sold in minimum 5 gallon quantities and I think it's about
$5 per gallon. If anyone's interested, let me know and I'll look up the
information and pass it along. It's supposed to be PCB-free, also.

The article also cautions against using motor oil for various reasons, among
which is that it attacks the resistor (actually, I think it's the additives
that cause the problem).




"Art Unwin KB9MZ" wrote in message
m...
"Keyboard In The Wilderness" wrote in message
news:fjUYa.31252$ff.5358@fed1read01...
Jav -- asked many times before -- for the answers go to Groups
Google.com
http://groups.google.com/

I don,t fully understand why motor oil should not be used
in a dummy load! I need to make one so I can calibrate
one of my instruments. I intend to use one of the uptodate
gallon paint cans that has a PTFE liner and solder the lid on.
Since we now have the means to use low wattage signals for
tuning up purposes there is obviously no reason to store it
in the shack . So what really is the problem with using
available oil instead of emulating the aproach of industrial
transformers or regurgitating old thoughts ?
Art








Search for Oil For Cantenna or Oil For Dummy Load

Mineral Oil works well for me.


"Javier Henderson" wrote in message
...
I got a Heathkit Cantenna recently, sans oil.

Where do I find transformer oil? The few industrial suppliers in my
area (Monterey, CA) want to sell me drums of the stuff. I only need
a gallon...

Is motor oil OK to use?

73,
-jav w6vms