evaporation

[frim]

What is the evaporation rate of 20W oil at 150*F and -2"Hg?

 

[25362]

This is a double posting isn't it ? Evaporation rates are generally expressed in mg/(cm².s).

Mineral oils may be regular or synthetic, inhibited or not. I wonder whether test method ASTM D2715 run under an air stream would be of help. I believe that given the low vapor pressure of the mentioned lube, evaporation rates would be very small when exposed to 150^oF and 27.92 in Hg absolute pressure. The supplier would be a good source of information for a considered answer to your query.

Then one has other ASTM tests to verify the resistance of a lubricant to molecular breakdown or rearrangement when exposed to air, such as D943, D1313, D2212, D2272, D2446, D2893, D5763, D6224, D6514. There is no clear rationale for selecting a particular one. Publications speak of "life-limits" beyond 10,000 hours of continuous use for synthetics and regular inhibited oils at 150^oF.

Again, the supplier would be a reasonable source of information on thermal stability.

I hope this posting is of some help.