[Amps] liquid cooling

[Larry]

The recent discussion on water cooling amp tubes got me thinking. Again. 
(not a good thing)

Basically I would like to play with liquid cooling but I can't/won't use 
water. While I was still working, I worked on a multi-kilowatt amplifier 
that was oil cooled. It went into the avionics bay of an aircraft where 
all the rest of the equipment was also oil cooled.

As I recall, the oil looked and felt like mineral oil, but I'm sure the 
military wouldn't use something that common and cheap and low flash 
point. At the time, I pulled up the MSDS for the oil but no longer have 
it and of course I can't remember the numbers.

K8CU talks about using ATF for cooling liquid here:

http://www.realhamradio.com/liquid-cooling.htm

Unfortunately, there is no indication in the article that he or anyone 
else actually used ATF. Now ATF contains sulphur compounds that eat 
silver plating and cannot normally be used in things like dummy loads 
because of this property. However, a set of heat exchangers used for 
tube cooling would not have that problem.

K8CU also mentions mineral oil and says it is not suitable due to the 
low flash point. I have to wonder about that because for one I would 
hope nothing in a system I would build would ever get hot enough to 
worry about flash point and two, it probably won't flash anyway due it 
being in a closed system with little or no free air/oxygen.

What I'm looking for is someone who has actually done liquid cooling 
with something other than water. No, I have no interest in "flat earth" 
theories, or what you think you remember from a thermodynamics class you 
sat through 40 years ago. I want actual test results and operational 
data from real world applications.

73, Larry

Larry - W7IUV
DN07dg - central WA
http://w7iuv.com