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Heat & Fiberglass...

3K views 19 replies 5 participants last post by  mitiempo 
#1 ·
Now, I know that they don't combine well at all, but there have been a few posts lately about keel bolts, and it got me thinking about mine. I've been trying to figure out a way to caress the steel bolts out of my cast iron keel for some time. After reading some tactics on automotive blogs, and working on my own, I know that heating a bolt that is stuck, is a good way to get it moving. I was wondering weather I could get a piece of plate steel with a 1/2" hole cut out and use it shield the bilge while I carefully (CAREFULLY!!!) heat the bolt with a torch. A few heatings and coolings should free the bolt and not have me worry about snapping the bolt in the keel... I guess I'm worried about heat transfer to the glass, etc.

Thoughts? I appreciate any input:)
 
#3 ·
Yea, I'm not sure why the spec sheet on that site says lead, but it is definitely cast iron. I've ground it down and faired it a few times. Here is the tech drawing that I meant to attach to the initial post to better illustrate what I mean.
 

Attachments

#4 ·
I guess the info on that site is incorrect. I guess if the threaded section has been moist at all it has corroded in place over the years.
You will have to heat the bolt throughout its length, and the keel will resist that as it is cool - or cold this time of the year.
Are you dropping the keel or just trying to pull a bolt for inspection?
 
#7 ·
Zinc coated steel. Last year I removed the nut off the foremost bolt, and and replaced it with new, partially to see if the bolt would withstand the re-torquing. No problems there. So I think I'm in fairly good shape, but I'd like to know for sure. Also thought of using penetrating oil over the course of a few weeks, but again, I don't know if that might have an adverse effect on the surrounding hull structure.
 
#8 ·
I don't think penetrating oil will harm the hull, but I am not an expert. The best to use is PB Blaster - it works better than any other. But I don't know how far it will penetrate along the bolt threads if they is corroded in place.

Perhaps someone else will post an answer.
 
#11 ·
Many hydrocarbon solvents, including gasoline, eats styrofoam on contact... that's because of the chemistry involved and not really a sign of much.
 
#10 ·
I would try penetrating oil instead of heat... PB Blaster works wonders.
 
#14 ·
You can combine the heat treatment with penetrating oil for better effect. Heat the bolt a bit, then add oil, let it set and cool a little, repeat. The heating and cooling, along with a bit of boiling of the oil, will help to work the oil into the appropriate bits. You might also try applying a bit of "persuasion" with an impact driver (used properly, they can work wonders at freeing seized threads).
 
#15 · (Edited)
Use of a heat gun would be a little more controllable than a torch, remove when fiberglass starts to turn brown and smoke.;) They use radiant heat so just the thing they are aimed at gets hot.
Or if there is room and you are REALLY determined you could rent a nut splitter, I say rent 'cause you are gonna need an industrial strength unit.
Hydraulic Nut Splitter, Hydraulic Nut Splitters, Nut Splitter, AUTO-SPLITTER, Fastorq Products, Fastorq Wrenches, Hydraulic Torque Wrenches, ASTM A194 2H Brinell, API and ANSI flanges
 
#16 ·
The term Nut Splitter makes me wince...:eek: The nuts won't be the problem, backing the 5 inches of threaded rod out of 40 year old cast iron is the real issue, but I suppose once the nut is gone, the PB can get waaaay down in there and do its thing... Thanks!
 
#18 ·
Grind two sides flat and then use a big ass wrench. ;)
 
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