Stuck screw

[Action]

I use Tef Gel.

Looks like good stuff.
However more expensive than most regular or marine based anti-seize products. Over $11 an oz compared to under $4 an oz. Or Marine at $5 an oz.

And would not work in high temp situations. Tef Gel is good to just under 600f.
The high temp anti-seize I used for spark plugs is good to 2200 degree f. And still less $ money.

And looking at Marine grade, looks like that is rated to 2400 degrees.
I have never used this version. 8 ounces may last a lifetime. Just over $24 on Amazon

 

[Comodave]

I don’t have spark plugs…

 

[Action]

Spark plug threads aren't the only thing that gets hot.

 

[Comodave]

Not much else on a boat except the engines get that hot.

 

[RedRascal]

I am unclear if this is just a bolt that goes through both the Seawise davit and motor or if the issue is with the motor screw clamps that hold the motor to a transom. If it's just a bolt sometimes cutting it off in 30 seconds with an angle grinder and replacing it with a new bolt may be quickest solution.

https://www.harborfreight.com/power...in-angle-grinder-with-slide-switch-58089.html

 

[Action]

Not much else on a boat except the engines get that hot.

Exactly. Same in automotive use. The engine is the heat source.
A lot of that heat is blown out the exhaust
The things that bolted to said engine do absorb a lot of heat.
Covers
Manifolds
Pumps
Turbo(s)
Be the engine a diesel or a bolt on outboard.

High temp can be used in low temp situations. Just not the other way around. And when high temp marine anti-seize is 50% to 75% less than the other stuff. Why get the other stuff?

 

[lwarden]

I spent quite a few years in the boat rental business a few decades ago and faced a lot of stuck bolts. The techniques listed in previous posts are some good ones for getting them out. Usually heat, tapping and an impact driver (and patience) were all needed to deal with them and after some practice it was rare to break one off. The main tool was heat, followed by tapping, then the impact driver.

One thing we always did when reassembling lower units or any area where there were dissimilar metals was to chase the thread with a tap, then when reassembling use Form-a-Gasket #2 (or OMC gasket compound) when reinserting. Once this was done it prevented salt water from entering the threads and next time the bolts came out easy peasy. Tef Gel is probably better but wasn't available back then.

 

[Action]

^^^^ +1

Technology (chemicals) has improved. Take advantage of everything available.

 

[huruta]

We used an anti seize product when installing the new spark plugs on the outboard. Will report back on product when we return to boat on Sunday.