Trojan Boat Forum

I need to remove a rusted bolt this weekend. I plan on using PB Blaster using the spray, tap, spray, tap, etc. method. Does anyone have any other suggestions in case this method doesn't work?

I know I may get flack for this .. but depending where they are .. some heat to bolts via a small torch and tap . You may be breaking the heads off the bolts otherwise then it a real pain to get them out

I agree with the heat depending where the bolt is located in the boat. Obviously you have to be careful using it in the bilge. I have used a heat gun for the same problem. Then a cold spray and the expansion and contraction may break it free. The PB blaster or similar also helps.

lots of pb blaster! most people dont give it enough time. If its really rusted I would spray it as many times as you can over a day or two. the more time it has to penetrate , the better chance you have of getting it out in one piece.

A Dremel tool, just cut and replace it. I keep a Dremel on board and use it all the time.

Here is a list of penetration oil tests from practical machinist website:

In a thread in the antique machinery forum, there was a discussion what to use to free up a part. Southbendmodel34 had mentioned a study in Machinist Workshop stating that Automatic transmission fluid and Acetone mixed was the best.
I just received a newsletter today from Tim Carter mentioning the same study. He had included the results of the test, which I thought interesting.

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


I am going to make me some of that ATF acetone mix. Not sure what the ratios are, just a guess 50/50

In a thread in the antique machinery forum

Isn't that this one????

I have heard good things about the ATF-Acetone mix. That said, cooling the bolt is a safer way to go than heating if you're in the bilge and penetrating oils used at room temperature don't work. Go to a welding supply house or other source of dry ice, and get the cold to the bolt head only, if you can. Insulate the adjacent material so that the dry ice cannot make intimate contact with it (cork gasket material would be my choice, or a Styrofoam cup), then make sure the dry ice can get to the bolt head. A pipe stuffed with shaved dry ice placed on the bolt head would be ideal. Hold the pipe in place, then force the dry ice onto the bolt head with a wooden dowel through the pipe. If you can keep it in place, dry ice mixed with acetone will yield a temperature equal to dry ice -- minus 109F. Liquid nitrogen down said pipe would be even better than dry ice, but I presumed no access to appropriate dewars, PPE, or prior experience working with cryogenic liquids. Acetone is of course flammable, being not much better than gasoline in that regard.

Steel has a coefficient of thermal expansion of about 6 microinches per inch, so were are not talking about opening up a lot of room on a half-inch or so bolt. The delta T that you'll get with heat will (likely) be higher, and therefore will be more likely to work, but failure with it could be catastrophic.

If you choose the cold route, you'll want to only use the change in temperature to make it easy for the penetrating oil to do its thing. Good ventilation would be in order. You would be ill-advised to turn the bolt when it is chilled thusly.

....And another thing. Have you tried a cordless (or pneumatic) impact driver? I got a cordless impact driver as part of a tool package and thought that I'd not get much use from it -- turned out to be a really useful thing. Be sure to try to both loosen and tighten the bolt as you let the penetrating oil of your choice do its thing. Let us know how you make out.

PPdog, it could have come from there as well, I have had a copy for a long time, and that was where the poster said it came from, either way, one of these days gonna try it.

About battery impact drivers +++ I did not think they would be any good either, wrong, I don't use my pneumatic now other than for very large bolts, mine claimed 200 lbs of torque.