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I got this in an e-mail. It was supposedly taken from the HAMB boards:

Penetrating Oils Compared


Finally, a useful e-mail!

Machinist's Workshop magazine actually tested penetrants for break out torque on rusted nuts. Significant results!

*They arranged a subjective test of all the popular penetrants with the control being the torque required to remove the nut from a "scientifically rusted" environment.*

*Penetrating oil ..... Average load*

None ..................... 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 was a "home brew" mix of 50 - 50 automatic
transmission fluid and acetone.*
*Note the "home brew" was better than any commercial product in this one particular test. A local machinist group mixed up a batch and all now use it with equally good results. Note also that "Liquid Wrench" is about as good as "Kroil" for about 20% of the price. *

Looks suspect to me. Were the tests done on the same bolt? Or was there separate, identically rusted and tightened bolts for each product? Looks to me like he broke it loose the first time, then just went and tested the rest in whatever order (Liquid Wrench better than PB? I don't think so) that makes his "home brew" stuff look like a miracle product.

Good point and the short answer is I don't know. I was wondering about the acetone. It evaporates so quickly that I have a difficult time believing it's really useful in that application BUT I posted it in case someone knows any facts about it & cares to comment OR wants to mix some home brew and do their own test.

I've used Kroil with amazing results. The study seems kind of bogus to me.

I like 50/50 Acetone-Marvels Mystery oil for stuck pistons, PB Blaster for most everything else.

That's the first thing that came to minde when I read it Bill. How do you get a half dozen fateners to rust exactly the same way? Don't know whether to believe any of this or not. I truly can't say one is any better than the other. but I've been using Kroil for years and I gotta say this, I just spent the last two years pulling just about all the parts off the bottom of my 1950, 3600 and have not ruined one singel bolt or screw and have wire brushed and reused almost all of the original fasteners. I actually contributed that to the fact that the truck was kept in a shed almost all of its 56 years before I got it and I also keep it in out of the weather.
To me a valid test of 6 different examples would entail a standard friction device so you could repeat the friction tests.
Denny Graham
Sandwich, IL

If they tested each penetrant several times with different bolts and got similar results each time, the results might be useful.

If they tested each penetrant only once, I'd take the results with a grain of salt.

Where did I read that a molasses solution was great? It might have been in an vintage Mercury outboard forum.

Someone once told me that the penetrating oil that Chrysler sells, I guess under the MoPar brand, is the best by far. I have not tried it but others to whom mentioned it have and sday its really good.

Liquid Wrench all the way.

Finding the original article, they soaked the bolts for 8 hours prior to loosening. I am sorry, however I do not have 8 hours. I do however soak things down, and use heat where possible.

Did you find it on line? Could you post the link? I'd like to read it.

I found this. http://bbs.homeshopmachinist.net/showthread.php?t=27429&highlight=penetrating+fluid+test
Scroll to post 18, it is the author of the test

I always end up snapping bolts off with a pipe on the end of a wrench. (My breaker bar only has 6 point sokets, so they don't always fit.) It normally doesn't matter what I do. Thats the nice thing about having a '70 GMC. They are still common enough for me to get other stock bolts, or order most of them from LMC for pretty cheap.

For those of us that work on cars for a living (like myself) breaking the bolts off is not an option, every attempt possible must be made to get the bolt out in one peice. Breking them off usually means more work, like having to drill them out, and in some cases, Heli-Coiling the hole to rpair the threads.

The ATF-Acetone mix sounds interesting, I hadn't heard of it before, worth a try.

I believe that different stuff works for different kinds of rust or different kinds of "stuck".
There is no one "best" penetrating oil for all situations.

I prefer PB Blaster for most stuff, but will always try something else with the hopes that it works better.

Wonder if acetone and PB wold work any better than plain PB?
Does the acetone help the oil to wick into the rust/stuck parts?

Grigg

Here's what I read recently John's Old Mercury Outboard forum.

http://www.pfs-ware.com/phpBB3/viewtopic.php?f=3&t=597

Old outboard motors....with bolts and blocks of different metal types and used in salt water....can be real buggers.

Can someone try the molasses treatment?

I read all of the thread and want to point out some of the highlights:

The author says the article incorrectly identifies it as ATF/Acetone. He apologized for the write-up mistake, and said he used POWER STEERING FLUID. He inadvertently picked up it up instead of the ATF.

Regarding the test procedure, here are some comments:

> "had a control and each piece was electrolytically rusted so it should be a pretty uniform job. As i recall, they were all torqued to a specific torque beforehand as well so there shouldn't be any question as to the validity of the results."

> "Unless my memory fails me, the test fixturing was a bunch of pins pressed in holes of fixed sizes. I would not have wanted to be in charge of trying to develop test fixtures for this and don't know that I could do any better, but pins in bores being pressed out is not quite the same as a bolt threaded into a hole. The latter involves much more surface area. Think about the linear distance if you unwrapped all of the threads from say 1.5" of a 12, 16, or 20 TPI bolt. That's a long way to try to get a penetrant to flow.

I think the corrosion conditions were much shorter duration than say a bolt that spent 5 years under your car in salt water etc. If I recall correctly, dwell time for the test fixtures in the corrosive mixture was rather short, even though it went through several cycles. I tend to think that corrosive adhesion comes from metal transfer from one surface to a mating surface through galvanic action....the longer it occurs the deeper it goes. Again, like I said, I am sure compromises had to be made in setting up the tests. Likely a guy can't spend 10 years rusting something so he can test penetrating oils "


I'm curious about the test results. I would like to go to a junk yard and try out the various fluids on bolts in the yard. It isn't a full-fledged design of experiments, but it will give me some idea if my results overlay the other test's results.

Bill

I find nothing else comes close to this product which is not on the test:

http://www.sprayproducts.com/penetrants-lubricants.php

Thanks Scott. It seems the test was done with power steering fluid instead of ATF if anyone is going to try the "home brew" they tested AND they soaked the test fasteners for 8 hours before testing. While it's not reasonable to expect an 8 hour dwell I have a bit of acetone and an old bottle of PS fluid. I might just mix a bit & see how it works the next time I have a frozen fastener.

I have never seen ANY of this stuff that actually worked.

Weeds

I've been fighting since last fall with a spark plug in a Minneapolis Moline that won't come loose. I've been taking turns spraying it with PB Blaster, Liquid Wrench, and Gibbs, and so far I've only gotten it to move about 1/8".
I might have to try one of these other concoctions, unless anyone has any better ideas.

Most power steering fluid is the same stuff as ATF, less some of the additives for clutch plate differences. (Dexron, Type F, Chrysler, etc.) The base oil is EP-32 hydraulic fluid, simply a lightweight oil. I don't see what difference if any, using ATF or PS fluid would make.
Jerry

Rich, just keep moving it back and forth....back and forth....back and forth. It will come out. Baaack and forth, back and forth.

That's kinda what we been doin'.

I'm a little skeptical of their test results too. From what I've seen working on my IH, PB Blaster soaks in better than Liquid Wrench. This was on 2 1" nuts that I had to remove to get the hitch off the rear to replace a broken sway arm. As for the torque used, it was me dangling in the air at the end of a 3/4" drive breaker bar with a 5' steel pipe over the last foot of the handle. I'm only 150 lbs. so sometimes I have to improvise.

I'll keep using both, just because I have Liquid Wrench in 1 qt cans, and the PB Blaster is in spray cans.