Loosening stuck bolts w/o shearing?

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Originally Posted by JohnnyK

I've never had any luck with the cold sprays on 'really' stuck bolts. Maybe it works fine on stubborn bolts.

Generally you need the bolt red hot. Whether it be from oxy-fuel or induction, that doesn't matter (I have an induction tool, but it's pretty cumbersome). As mentioned, propane takes so long (and won't ever get hot enough as far as I am concerned), you start heating other parts as you wait.

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Actually that sort of makes sense. Freezing the bolt changes the temperature perhaps -40*C, while heating it might add several +100*C's, which means the change in volume is gonna be that much bigger. I'll try the acetone/ATF fluid + an induction tool. :)

You are going to have a hard time getting heated what you need heated. All you can heat is the head of the bolt and what is really stuck is the threaded end on the other side. To get that hot enough you are going to have to heat the head up to cherry red for a while. Even with that, you aren't going to heat it enough but you will soften the head end so much that if you don't let it cool before trying to loosen it, you will just twist it off. Like I said, try just loosening it a tiny bit, spray your favorite stuff on it and then work it back and forth till it comes out or breaks.

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Originally Posted by David T

You are going to have a hard time getting heated what you need heated. All you can heat is the head of the bolt and what is really stuck is the threaded end on the other side. To get that hot enough you are going to have to heat the head up to cherry red for a while. Even with that, you aren't going to heat it enough but you will soften the head end so much that if you don't let it cool before trying to loosen it, you will just twist it off. Like I said, try just loosening it a tiny bit, spray your favorite stuff on it and then work it back and forth till it comes out or breaks.

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That’s one thing about the battery trick. You would expect the most heat at the area of most electrical resistance. We are assuming the threads are rusted/corroded. Rust is a poor conductor, so maybe the most heat would be right where it’s needed. Not sure if that would make it likly to strip the threads out, but at least the bolt/stud should come out.

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Originally Posted by Helirich

That’s one thing about the battery trick. You would expect the most heat at the area of most electrical resistance. We are assuming the threads are rusted/corroded. Rust is a poor conductor, so maybe the most heat would be right where it’s needed. Not sure if that would make it likly to strip the threads out, but at least the bolt/stud should come out.

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I agree. Probably puts the heat right where it's needed. Unless it's so much heat it welds that spot.

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Originally Posted by David T

You are going to have a hard time getting heated what you need heated. All you can heat is the head of the bolt and what is really stuck is the threaded end on the other side. To get that hot enough you are going to have to heat the head up to cherry red for a while. Even with that, you aren't going to heat it enough but you will soften the head end so much that if you don't let it cool before trying to loosen it, you will just twist it off. Like I said, try just loosening it a tiny bit, spray your favorite stuff on it and then work it back and forth till it comes out or breaks.

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True. Maybe it would make sense to apply the heat first, only to make room for the penetrant to enter between the bolt and the engine block. Then let it cool before proceeding as you suggest. Hmm...

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Originally Posted by Bitsyncmaster

I agree. Probably puts the heat right where it's needed. Unless it's so much heat it welds that spot.

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Yeah - that's the rub. There is an element of unpredictability there, that I don't appreciate.

Going with the thin (acetone) phase, that looks like it has ATF dissolved in it. The thick (ATF fase) seems not to be diluted.
Attachment 67887

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Originally Posted by SupercoolBill

Been breaking bolts left and right on my project. A buddy just gave me one of these to try. Attachment 67883

Sent from my SM-G970U using Tapatalk

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I'm also curious about the induction unit. Seems like a slam dunk if you're working to loosen a nut and have access. But how well will it work on a bolt or stud? Let us know what you find if you try it.

Ron

Heat and a battery powered impact gun that doesn't have alot of torque

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Originally Posted by Bitsyncmaster

I agree. Probably puts the heat right where it's needed. Unless it's so much heat it welds that spot.

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I admit I’m a poor welder, but I find it nearly impossible to weld rust or aluminum corrosion. Also, welding steel to aluminum is very difficult. Lol. But we all know Murphy will help at times like that.