Interesting observation- alcohol vs oils

[tom slick]

the air force has adopted using isopropol alcohol as it's standard cleaner/solvent for most aircraft engine related cleaning duties. it's cheap and works well and leaves no residue. the thing i have noticed is that it has no problem breaking down turbine engine oil or mil spec hydralic fluid. spray a little on alc. your oily surface and the oil wipes right up. the interesting part is that it doesn't touch automotive oils. spray alc. on them and all you do is thin them a little and smear the oil around.
why is that? is it due to the aircraft oils being synthetic?

 

[labman]

Rule #1 on solubility, like dissolves like. I don't think a PAO would make much difference from dino. IPA should cut a polar material such as as ester based oil better than it cuts a strictly unoxygenated material. Also I thing some aircraft hydraulics contain chlorine or phosphates for fire resistance, again more polar material subject to the highly polar IPA.

 

[tom slick]

thanks for the reply. let me see if i can intrepret it from chemist vernaculer to mechanic lingo. the types of oils used in aircraft are "polar" and the ipa (india pale ale?

) is polar so it easily breaks them down?