HELPFUL TIP: Effectiveness of Penetrating Oils

Machinist's Workshop recently published some information on various
penetrating oils. The magazine reports they tested penetrates for break out
torque on rusted nuts.




I WANT TO CAUTION YOU THAT PENETRATING OILS WILL SOFTEN SOME PLASTICS AND WILL DISSOLVE OR REMOVE PAINTS, LACQUERS, AND VARNISHES.

Try a little on a test piece or in an inconspicuous place first if your item has plastic parts, or a painted finish.

Below listed, a subjective test was made of all the popular penetrates, with
the control being the torque required to remove the nut from a
"scientifically rusted" environment.

                        Average torque load to loosen



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

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

                        PB Blaster .................... 214 pounds (mineral
oil in a solvent carrier, often acetone or mineral spirits)

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

                        Kano Kroil .................... 106 pounds (mineral
oil in a solvent carrier, often acetone or mineral spirits)

                        ATF - Acetone mix............53 pounds (ATF (automatic transmission fluid) -
predominantly mineral oil).


I have seen a mix of diesel fuel and a little gasoline work well, but, as in the case of all oils and solvents, it's very flammable.


I use a solution that was published years ago in "American Gunsmith" magazine. I forget what they called it--I call it "Wonder Oil" It is very effective at dissolving dried oils, grease and "gunk" (that's a scientific term). Like WD-40, it also is water-dispersing, and leaves a slightly oily residue. It does have a strong smell, but it's a lot cheaper than the commercial penetrating oils. All the ingredients can be purchased from WalMart or a hardware store. Here's the formula:

4 parts Mineral Spirits
4 parts Kerosene
1.5 parts Marvel Mystery Oil
.5 parts Rislone

(You can get Marvel Mystery Oil and Rislone at auto parts stores if they're not available elsewhere.)

Here is a sample of how to measure it if you are using English measurements (fluid ounces, cups, teaspoons, etc.):

4 cups each of Mineral Spirits and Kerosene, one and a half cups Marvel Mystery Oil, and a half cup of Rislone.

CAUTION: These amounts will produce 10 cups, or 2 1/2 quarts of oil.  You may want to use a smaller amount--just reduce proportionally.

WARNING: Like other penetrating oils, this will dissolve paints, varnishes, etc. and soften or distort some plastics and rubber compounds.

I keep this solution in used plastic oil cans--you don't need to clean the old oil out, just pour the solution in and the oil will dissolve into it.  You can also use empty brake fluid or oil treatment bottles as well.


I use a refillable aerosol can when I need to spray the solution. Harbor Freight used to sell them, though I can't find it now on their website. They used to be $8 or $9... I see them on eBay, however, and also on Amazon.com. Here's an example:

Amazon.com Refillable Aerosol


These are a really neat item--It consists of a metal can similar to a paint spray can, with a screw on top, and a valve stem. You fill the can half full of liquid, screw the top on, and pump air into it, using an air compressor, an air hose from a service station, or even a bicycle tire pump. They have several nozzles included so you can spray oils, glass cleaner, water, etc.

So, here's another item you can file away as a helpful tip.


Smitty