Gunsmithing Rusted Bolts/ Penetrating Oil

[yotefever]

Thought I would post this info here because I know I'm always looking for a better penetrating oil for those stubborn screws.
I haven't tried it yet but will be next time I work on my jeep or changing a scope base or ......



Some interesting information for the Mechanically Inclined.

For all of you that are mechanically inclined.....
Penetrating Oils Compared

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 ............... 103 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.

 

[BOLTRIPPER]

Re: Rusted Bolts/ Penetrating Oil

don't forget the cheater bar and swearing in Latin.....

 

[Powder_Burns]

Re: Rusted Bolts/ Penetrating Oil

Shock helps a lot too. I go through this a lot, and have even seen socket head cap screws snap in half. My procedure consists of a liberal dose of PB, a few swings of the hammer with a brass drift or a pneumatic hammer, hitting a cheater bar with a hammer to break em free. Good times, nothing like expending all of your energy in 5 minutes per bolt. I think I'm gonna have to try the ATF/acetone thing some day. Wonder if it climbs up threads like PB does.

 

[chad3]

Re: Rusted Bolts/ Penetrating Oil

I've always been happy with both PB and Kroil. My cousin got me hooked on the Kroil after he could get it from his company for me for free.
Switched jobs, so now not so free, but I still have some laying around before I need to spend the cash.
Chad

 

[scout67]

Re: Rusted Bolts/ Penetrating Oil

I usually use kroil. But I have had some success with "Freeze & Release" from Loctite. I has worked for me on a few occasions when Kroil did not.

 

[Clark]

Re: Rusted Bolts/ Penetrating Oil

Two days ago I got a barrel off a beat up old 1942 Russian 91/30 rifle with rotten bore and some rust.
The barrel has been on there for 68 years.

I cleaned the collet and barrel, where they were to touch, with Alcohol, and then dried the surfaces.
I put powdered sugar on the skinny part of the barrel, as the fat part of the barrel is tapered.
I put the barrel in a 1.5" O.D. Aluminum split collet I made on the lathe.
I put the collet in a barrel vise and used ~300 foot pounds on the hardened 1/2-13 bolts to tighten the home made barrel vise.
I heated the barrel around the chamber with a propane torch until it was too hot to touch.
I put Kroil on the barrel to receiver junction in front.
I weigh 190 pounds and I sat on the 3 foot cheater bar... = 570 foot pounds of torque.
No go.
There was too much compliance in the skinny part of the barrel so a 20 pound sledge hammer would be no help.
I put Kroil on the junction a couple more times and waited for 10 minutes.
Then when I sat on the cheater bar, it came loose.

With Mausers, I can get a collet around the chamber, and the 20 pound hit on the action wrench means not having to wait 10 minutes and not having to use the torch.

 

[scout67]

Re: Rusted Bolts/ Penetrating Oil

Silly question, but why did you heat the barrel instead of heating the receiver. Normally you heat the female threads so that they expand.

 

[Clark]

Re: Rusted Bolts/ Penetrating Oil

I am throwing the barrel away.
I am going to use the receiver.
The barrel will get hot, crack some rust, and then cool and shrink.
The Kroil will creep in better.

You are right that heating the receiver would work better, but I don't want to do that.

 

[Glen Seekins]

Re: Rusted Bolts/ Penetrating Oil

Loctite Freeze works wonderfully. It gets very cold -45 and shocks the rust enough to bust it loose allowing the oil to penetrate. After about 5min of soaking its ready

 

[cav has been]

Re: Rusted Bolts/ Penetrating Oil

Some of us cheap bastids been known to use liquid propane to freeze a part to release it. Also works for a "shrink fit". Po folk gots po ways.

 

[jbell]

Re: Rusted Bolts/ Penetrating Oil

Talking about the post that heated the barrel and not the reciver as conventional wisdom says, I have heated studs or broken bolts very hot when they are stuck into something you dont want to apply direct heat to. You let the stud heat soak for a minute or so to heat up the part the stud is threaded into and then spray the stud (or barrel in this case) w/ penitrating oil. In doing this you are not trying to use the penitrant to chemically loosen the seized part but cool it very fast, shrinking it, and keep the heat in the housing and then removeing the stud. Cant wait to try acitone and atf!

 

[former naval person]

Re: Rusted Bolts/ Penetrating Oil

Good tip...FWIW...Ed's Red Bore solvent is similar...those using Ed's Red might try it for the penetrating oil as described.

 

[The Mechanic]

Re: Rusted Bolts/ Penetrating Oil

Have a hard time believing that WD40 and PB are comparable. I have not had very good luck with WD.
<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Powder Burns</div><div class="ubbcode-body">Shock helps a lot too. I go through this a lot, and have even seen socket head cap screws snap in half. My procedure consists of a liberal dose of PB, a few swings of the hammer with a brass drift or a pneumatic hammer, hitting a cheater bar with a hammer to break em free. Good times, nothing like expending all of your energy in 5 minutes per bolt. I think I'm gonna have to try the ATF/acetone thing some day. Wonder if it climbs up threads like PB does. </div></div>
Totally agree with shock load. I have a few impact that will supply enough force to break loose or just plain snap off bolt heads as sometimes this is the next best solution.