What is the best Penetrating Oil?

I would bet you have some of these penetrating oils kicking around your shops or tool boxes like I do. I have a gallon of WD-40 that has to be about 25-30 years old now in the back of my work shop. Of course there is the obligatory can of PB Blaster in my roll about tool tray for those quick jobs. Now that I have read about the choices like you will, I am sure you will find that not only is there a  cheaper solution that works. This article is all over the internet, so it must have some validity.

A study done by Machinist’s Workshop magazine in their April 2007 issue looked at different penetrating oils to see which one did the best job of removing a rusted bolt by measuring the pounds of torque required to loosen the bolt once treated. If the study was scientifically accurate, it turns out a home brew works best!
Here’s the summary of the test results:

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 (50-50 mix)

(ATF is automatic transmission fluid)
Acetone will dissolve paint! The fumes are not to be breathed in an enclosed area.

If you mix it up fresh, put it in a bottle for storage. Just know that the two fluids have different densities and will separate out. Just shake the bottle before use.

The test used some machined up test devices, ran them in a salt bath and a high moisture content bath so they would rust up good and tight. Then using a press, broke them apart using the aforementioned solutions and recorded the results.

WD-40 is great stuff and been around forever. You can visit their website by clicking on the WD-40 link to learn why it was created and a million uses. I used it on latex wall paint to remove creative art projects from my kids with Crayons.

PB Blaster is a great product but it pales in comparison to the acetone/transmission oil combination. I like this product more than I do Liquid Wrench. I use this on just about everything that has to come apart or going back together that doesn’t need anti-seize compound.

Liquid Wrench is another one of those products that has been around since…well forever. I didn’t know it was a better product than PB Blaster looking at the results above. The company also makes “GUNK” engine cleaner. Love the product but the smell! Don’t you think that Liquid Wrench has the smell of diesel in it?

Kano Kroil I have heard of, but have no experience with the product. Looking at the results the product appears to really do its work. In reading up on the product from a couple of sources, people swear by it, including the US Navy who uses it by the 55 gallon drum. You “cannot” buy this at any parts store, but only direct from the company on their website. One web source says to check your local gun store as it is great for lubricating. I copied this from a website:

The Oil That Creeps, loosens frozen metal parts.  A scientific discovery reduces the surface tension so that this amazing solvent creeps into openings as small as one millionth of an inch.  Wherever there is corrosion due to heat, salt water, chemical action or weathering Kroil will loosen metal joints in a few minutes time, saving labor, equipment and temper.  It dissolves gum, dried grease and oil, removes rust and carbon deposits without attacking the metal and provides proper lubrication.  Resists wetting so prevents rust.

I hope this “primer” on penetrating fluids has crept in to loosen up your ideas of what you might want to carry on your shelves for loosening tight nuts and bolts. We love tight nuts but we also want to be able to get them loose somewhere down the road. Just remember, “It only takes one loose nut to scatter a car of a 1000 pieces all over the road.”


About alfadoc

I have been involved in Alfa Romeo cars since 1970 when I bought my 1600 Veloce spider. It was in 1972 that I started the Veloce Register for 1600 cars. It was in 1998 that I added the Sprint Veloce, 750 Spider Veloce and Sprint Speciale registers. Currently I own 2 Alfas: a 1994 164 Quadrifoglio.and a 1991 Spider "Automatic"
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