Make Your Own Kick-Ass Penetrating Oil

"Urambo Tauro" (urambotauro)
11/10/2015 at 13:30 • Filed to: wrenching, rust, oil

It has long been said that if something doesn’t move, but should, use WD-40. But what if you’re trying to free a rusted bolt? You can do better than that...

One of the more popular penetrants is PB B’laster. The styrofoam cup test is a favorite method when comparing it to WD-40. But there are also other penetrating oils on the market that claim to be better. So Machinist’s Workshop magazine published an !!!error: Indecipherable SUB-paragraph formatting!!! , recounting the writer’s attempt to create a controlled environment in which to test each substance. The method went far beyond melting cups, focusing on resistance.

PENETRATING OIL - AVERAGE LOAD

None - 516 pounds
WD-40 - 238 pounds
PB B’laster - 214 pounds
Liquid Wrench - 127 pounds
Kano Kroil - 106 pounds
ATF / Acetone Mix - 53 pounds

The test showed that anything, even WD-40, was better than dry-wrenching. But the winner, by a considerable margin, was the home-made mix consisting of 50% automatic transmission fluid, and 50% acetone. This 1:1 ratio allows the thin acetone to carry lubricant deep into the threads of your target bolt.

The ingredients are easy to come by. Acetone can be found among paint stripping chemicals at your favorite hardware store, or you can find it in nail polish remover.

But ATF and acetone don’t like to stay mixed. The home brew will separate overnight, and is therefore a “shake well before use” product. To facilitate mixing, I avoid keeping it in a spray bottle (which would hold the first few squirts of fluid in the straw). Instead, I use two containers:

I start with the 16oz bottle, adding 6oz of acetone & 6oz of ATF. This leaves room for mixing. After a good shake, the mixture gets poured into a little 4oz bottle that previously held friction modifier for my differential. This little bottle has a nozzle on top. I refill the little applicator bottle as necessary, then mix up a new batch once the 16oz bottle is empty.

This solution works great, but the test featured in Machinist’s Workshop is over 8 years old. Is it time for a new test? Are there better formulas out there?

DISCUSSION (12)

RamblinRover Luxury-Yacht > Urambo Tauro
11/10/2015 at 13:39

It’s the convenience of the spray can you pay for, largely. This is known. Also, the acetone/trans fluid mix works best given ability for a physical soak, which isn’t always possible.

On a related note, rather than keeping starting fluid for a gas engine with fuel problems, carburetor cleaner burns pretty well and doesn’t go BANG, and better still can be an eyedrops bottle full of ordinary gas. Any gas engine that doesn’t start from one or the other probably shouldn’t be made to “start”. Plus, your squirt bottle can have two-stroke oil in it.

Smallbear wants a modern Syclone, local Maple Leafs spammer > RamblinRover Luxury-Yacht
11/10/2015 at 13:44

Also brake cleaner for starter fluid.

jariten1781 > Urambo Tauro
11/10/2015 at 13:45

Liquid Wrench is good enough, plentiful enough, and cheap enough that I haven’t used an ATF mix in a long-long-long time. Was a life saver back in my college days though.

RamblinRover Luxury-Yacht > Smallbear wants a modern Syclone, local Maple Leafs spammer
11/10/2015 at 13:48

Well... depends on the brake cleaner. My favorite stuff is the non-polar tetrachloroethylene stuff, which is notably not any good for burning.

911e46z06 > Urambo Tauro
11/10/2015 at 14:13

If you really want to redneck it up, use Ratfish oil.

SnapUndersteer, Italian Spiderman > Urambo Tauro
11/10/2015 at 14:26

I’ve only been using Kroil for the past 8 years

Mustafaluigi > Urambo Tauro
11/10/2015 at 16:54

Because of that article I started using Liquid Wrench. However since it came out WD started making sprays dedicated for loosening rusty bolts. I wonder what the test would show if it was redone with the dedicated fluids from the two.

kanadanmajava1 > Urambo Tauro
11/10/2015 at 17:54

I have used acetone + ATF mix at some point. Using it from a spray bottle would be really convenient but I wasn’t able to find any bottle that could withstand the mixture. I just used bottle and dipstick method.

eBay was offering some cheap acetone proof spray bottles (for nail polish removal) but I didn’t manage to buy those for testing.

XJDano > RamblinRover Luxury-Yacht
12/05/2015 at 23:36

I have had to dabble so e gas on the air filter, then put filter in place & it usually starts right up. Unless it’s between 0-32°F than sometimes needs repeating. Have used on generators & 8hp wood Chippers.

Invinciblejets > Urambo Tauro
04/22/2016 at 13:54

I’ve always used pb blaster

But Shit may have to give this a try it on the studs for my water pump housing on the front cover ...they are like fused in. Someone may have even jb welded them. I pray not.

Bob > SnapUndersteer, Italian Spiderman
01/24/2020 at 18:10

Thank you. We were really wondering what you used.

SnapUndersteer, Italian Spiderman > Bob
01/25/2020 at 11:18

Well, now you know!