tst wrote:Penetrating Oils
Machinist's Workshop MagT recently published some information on various penetrating
oils that I found very interesting. Some of you might appreciate this. The magazine reports
they tested penetrates for break out torque on rusted nuts.
They are below, as forwarded by an ex-student and professional machinist. They arranged
a subjective test of all the popular penetrates with the control being the torque required to
remove the nut from a "scientifically rusted" environment.
*Penetrating oils ........... Average torque load to loosen*
No Oil used ................... 516 pounds
WD-40 ..................... ... 238 pounds
PB Blaster ...................... 214 pounds
Liquid Wrench ...............127 pounds
Kano Kroil ..................... 106 pounds
ATF*-Acetone mix............53 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 about 20% of the price.
Steve from Godwin-Singer says that ATF-Acetone mix is best, but you can also use ATF
and lacquer thinner in a 50-50 mix. *ATF=Automatic Transmission Fluid
I must be the only person in the world that has actually read the article!
The last test you want is a "subjective test", you want an objective test.
Eitherway, there were no bolts, no torque, no nuts, no "scientifically rusted" environment, no ATF-acetone mix. Basically the article was from a well meaning person but is not very useful and I doubt has any real accuracy. Bogus
This person rusted steel dowel pins in reamed holes for somewhere around 12 hours in saltwater, measured the force, not torque, to push out the pins. A total of 3 pins per test. The ATF was really power steering fluid. No data was listed and no statistical analysis was presented. Without seeing the actual data we will never know for sure but a sample size of 3 per oil is likely completely useless.
I did a study that came out in Green magazine , May 2010, comparing oils using the same pin method, also included bolts and nuts. Rusted in an alternating salt water bath and air dry for 6 months. Larger study with statistical analysis and I got much different results. I believe I did 6 pins and 20 bolts for each oil. I did not calculate the power for the statistics but I expect you would need several hundred samples per oil to get any real validity. However, in my study there was no difference in the oils tested including ATF-Acetone
When folks say " I use brand X and it is the best" I think...how do you know? If all stuck bolts were essentially the same then getting results with a brand of oil would be useful but there is so much variability with stuck bolts that I am not sure " brand X works better than Brand Y " statements are all that useful.
I wrote to several companies including Kroil asking for any peer reviewed publications that supported their claims of superiority. The only one that responded was PB Blaster. Several request to Kroil went unanswered so I take their lack of response as an indication that they have no data to support their claims. PBBlaster did have some data but they only shared their ATF-Acetone test, not any with competitors.
What does all that mean? They likely all perform basically the same including WD-40 which is a penetrating oil also. Some may work slightly better with wet rusted bolts, some better with dry rusted bolts, some better with bolts seized in aluminum, etc..
If you are happy with Kroil, PB Blaster, mouse urine, then that is what I would use. I am now using Kroil since I stumbled onto 2 gallons. Once it is gone then I would go back to PB Blaster or Wal Mart. The engineer at PB Blaster that discussed their testing with me restores old Case tractors so at least we have something in common.
ATF-Acetone does not mix in a 50-50 ratio. Not sure what the correct ratio is but it is not 50-50.
If I was going to make my own, I would use an oil, ATF is fine, a polar solvent such as acetone, a polar protonic solvent such as isopropyl alcohol ( not rubbing alcohol but "heet" brand of fuel line deicer), and mineral spirits to thin. I have no idea It will work any better than others but makes more sense than ATF-acetone in a 50-50 mix.