You guys probably all know this already, but I ran across it and thought I would share it here.

"Machinist"s Workshop" recently published information on various penetrating oils. The magazine reports they tested these products for "break out torque" on rusted nuts and bolts. A subjective test was made of popular penetrating oils, with the unit of merit being the torque required to remove the nut from a "scientifically rusted" bolt.

Average torque load to loosen nut:

No Oil used ........................516 foot pounds

WD-40 ..................... ........238 foot pounds

PB Blaster .........................214 foot pounds

Liquid Wrench ......................127 foot pounds

Kano Kroil .........................106 foot pounds

ATF/Acetone mix...................... 53 foot pounds

The ATF/Acetone mix is a "home brew" mix of 50/50 automatic transmission fluid and acetone. Note this "home brew" released bolts better than any commercial product in this one particular test.

Our local machinist group mixed up a batch, and we all now use it with equally good results. Note also that Liquid Wrench is almost as good as Kroil for 20% of the price.

ATF/Acetone mix is best, but you can also use ATF and lacquer thinner in a 50/50 mix. ATF = Any type of Automatic Transmission Fluid. This was in one of the Military Vehicle Club newsletters >>

Great info. Surprised that the old candle trick wasn"t tested. Can"t be beat.

Interesting. My favorites have always been PB Blaster and Kano Kroil. I always thought they were about the same as far as loosening rust power goes, but the Kroil beats by a fairly wide margin. The only thing I used WD 40 for was for a lube when I surface ground aluminum.

Would you believe if you checked the archives you would find this listed many times in the past years.
By the way I have said for over a decade ATF works well to free up parts and engines

I just now mixed up a small batch of ATF and Acetone, and the mixture has seperated into its two parts in the jug after an hours time, so will need to be shook before each use, but I am gonna try it as a penetrant and see how it works. I have been using Deep Creep from Sea Foam or PB Blaster with good results.

yes - posted many times - once by me when I thought it was new too!

But when all's said and done, nothing beats heat. Works better than all of them, and there's no waiting time.

let us know what results you get. Sometimes real world is a lot different than in the lab.

Ah but heat does not always work either. I just did a ATF/heat thing on a part to free it up and that did not work I ended up having to got a step past that and slip the outer part open to remove the other part