PB Blaster is Snake Oil

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liveaboard
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Re: PB Blaster is Snake Oil

Post by liveaboard » Tue Jan 15, 2019 12:05 pm

I concur;
People say this one or that one really works, but I stopped believing any claims of penetrating oils long ago.
If you can get it to move, however slightly, the stuff will work in fairly quickly.
I took out some mild steel porthole bolts that had been installed 100 years earlier. They came out easily; and I paused to give thanks to the shipyard worker who had so thoughtfully greased the threads back in 1910.
Just plain grease I think. They didn't have them fancy products available.

John Hasler
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Re: PB Blaster is Snake Oil

Post by John Hasler » Tue Jan 15, 2019 2:52 pm

I've never expected penetrating oils to break down rust. What they can do is soak into any porosity that is present and provide a small amount of lubrication to some of those parts of the joint that are not chemically bonded by the rust but are forced together by its expansion. This permits a larger fraction of the force you are applying to to go toward breaking up the rust. It's a small effect but it can be the difference between twisting off the bolt and unscrewing it.

The advantage of using a mixture of a very low viscosity solvent such as acetone and an oil is that the low viscosity of the mixture permits it to flow into the pores reasonably quickly and leave the oil behind when the solvent evaporates.

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