That's part of how it works I think. The acetone is so thin it can penetrate the micro holes in the rust and being a good solvent it breaks some of it up. It carries some of the transmission fluid with it and evaporates leaving the oils. I assume some of the acetone that penetrated also breaks some rust up when it evaporates and the gaseous acetone needs to escape. The transmission fluid is a very thin oil and loaded with detergents and dispersents. It's an old method but the SAE tested it a few years ago and all there results favored it over the commercial products. By good margins too. MEK works well too.
It works good for cleaning guns and carbon fouling too.
It might work OK for cleaning guns but you still want to put a finish coat of some oil product that won't evaporate. Otherwise you end up with a ball of rust.
Actually I tend not oil my guns. Actions aren't really meant to be oiled and oil causes more problems than they solve. Holds dirt and and that causes more wear and jams. A very thin film on the barrel and outer parts when storing. All oil should be removed before going out to the field though.
I've heard that and tried it but I don't think that's actually true. Personally I've never seen any better performance from that than from Kroil, or even PB Blaster.
I've also used a MAP gas torch and a crayon (get the metal hot and melt the wax of the crayon into the stuck threads) or just a plain old gas hatchet to heat seized nuts to a dull cherry red before hitting them with the impact wrench.
Pb Blaster was good but they changed the formula and it is noticeable. Kroil is the joint but can be hard to find sometimes. Honestly after years and years Kroil and red mix works just as good, but kroil has other uses besides just this one.
I've done the torch and wax method and it works good. However I haven't found the wax works all that much better than just heating the the rusted bolt alone. The wax just seems an extra messy step that isn't needed. 98% sure it's the heat expansion that does all the work.
Yes, I think that you're right about the heat doing the bulk of the work in breaking the rust.
Any particular tranny fluid that you found to work well? There's so damn many different types these days. Probably all basically the same but some additive differences, and maybe not even that. I remember GM's Smurf oil not having an equivalent for the longest time and then, suddenly, Redline's latest Dexron equivalent was "approved". (And now that I think about it Ford used the exact same transfer case I'm thinking of; wonder what they required?)
Honestly for this application I don't think it matters. The different grades have mostly to do with foaming and certain metal compatibilities. Like I know the different kinds came about when whale oil was removed from transmission fluids. Something about whale oil made it the bomb additive for ATF. When it was removed there became compatibility issues and the different manufacturers came out with specific blends to address the problem in their particular trannies. They are all thin oil and high detergent though and that's what we are looking for here.
So Dexron or type "T" it is. Wonder if synthetic vs. dino has any bearing?
Interesting about whale oil too. Didn't realize ATF used it as a component at one time. I do know that really great electrical contact cleaner/lubricant used dolphin oil for some reason. Cleaners and lubes compounded with that product (Caig Labs Cramolin products) worked great and lasted forever. Alas, those compounding are no longer available either.
Hey man, I haven't done that kind of testing and don't know if anyone has. I'd say use what you got. Some people swear used burnt up atf works the best is all I know.
Apparently whale oil was good for everything. So it would seem.
Element 99 