Favorite penetrating oil that DOESN'T STINK!

[MedSailor]

I tried to hire a diesel mechanic for the first time in 12 years of old boat ownership. He didn't seem excited to do the job and told me to apply penetrating oil to the rusty prop-shaft coupler several times and then maybe he'd come back and do the work.

Hmmmm..... if it was easy, I would have done it myself.

I've never been a penetrating oil kind of guy. I prefer the "heat beat and repeat" method. But I took his suggestion and bought some Kroll oil and applied it in copious quantities.Several days later, as I was approaching the boat, I noticed a strong "simple green-like" smell. It was the Kroll oil! My entire boat stinks now, and I can smell it from the dock.

Needless to say the kroll oil will not be used again. What about PB-blaster or "break-free"? Any other favorites that don't get you high like brake cleaner does, or smell so strongly that it overpowers the usual eu-du-boat?

MedSailor

[Geoff54]

PB-blaster works but it does stink

[poopdeckpappy]

Pb is good stuff

[chuck53]

PB is good but Liquid Wrench is even better.

[DannyboyUpstate]

The thing about penetrating oil is that it's designed to break rusted parts apart. Not leave a pleasing aromatic fragrance.

Also, Kroil does not smell like Simple Green.

[zz4gta]

Kroil, PB blaster, or liquid wrench. All 3 work pretty well if given enough time to stink up the joint.

Heat should be used as a last resort. Another thing you can try is having a welder come out and weld a new nut onto the one that you will probably round off. Sometimes the heat from the welding is almost enough to break it free. Works reall well, but I wouldn't re-use the hardware.

[SVTatia]

Whatever oils is used, a word of caution.

I have read a post by Maine Sail to ensure you don't let the penetrating oil get anywhere near your transmission shaft as it will ruin the seals with catastrophic results.
Unfortunately I don't have the link to the post. But be careful.

[bljones]

yep, be careful wiht penetrating oil- a little goes a long way. you don't need to immerse whatever you are attempting to unstick in a vat of the stuff. You don't want to get anywhere near transimmission seals- they don;'t like each other.

Penetrating oil doesn't like to work alone- to get the best results, give it some help. Brush all of the loose rust off the parts to be unstuck. Spray a shot, have a cup of coffee, come back, wrench on it. spray it with another shot. if it's still stuck, spray it with another shot, leave it overnight, spray it again in the morning, wrench it again in the afternoon.

[chuck53]

The vibration from light hammering also helps.

[Fstbttms]

The April/May 2007 edition of Machinist's Workshop did a test of penetrating oils where they measured the force required to loosen rusty test devices. Buy the issue if you want to see how they did the test. The results reported were interesting. The lower the number of pounds the better. Mighty interesting results for simple acetone and tranny fluid!

Penetrating oil . Average load .. Price per fluid ounce
None .................. 516 pounds .
WD-40 .............. 238 pounds ... $0.25
PB Blaster ......... 214 pounds .. $0.35
Liquid Wrench ... 127 pounds .. $0.21
Kano Kroil ........ 106 pounds .. $0.75
ATF-Acetone mix.. 53 pounds .. $0.10

The ATF-Acetone mix was a 50/50 mix (1 to 1 ratio).