I had forgotten that, so no great rush in dealing with the stud issue to save a few bucks.
Good. You've got three months to deal with the stud issue before your fingers freeze solid and fall off
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Keel stud chemistry
- Thread starter degas
- Start date
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Potential Values (Anodic Index)
If you want to take the most conservative approach, I'd use a more active stainless steel bolt and washer combination, then apply dielectric grease generously to help electrically isolate the stainless steel from the cast iron. Something like this dielectric grease would work well.
This may also be more precaution than necessity, but you could add re-greasing the keel bolts to your annual haul-out maintenance routine.
- Cast Iron: ~-0.69 V (more anodic/active)
- Stainless Steel (Passive 304/316): ~-0.05 to -0.08 V (more cathodic/noble)
- Stainless Steel (Active): ~-0.56 to -0.58 V (much closer to cast iron, with a potential difference of only about 0.11 V)
If you want to take the most conservative approach, I'd use a more active stainless steel bolt and washer combination, then apply dielectric grease generously to help electrically isolate the stainless steel from the cast iron. Something like this dielectric grease would work well.
This may also be more precaution than necessity, but you could add re-greasing the keel bolts to your annual haul-out maintenance routine.
......................... until somehow, someway, in some undetermined fashion, water enters the threaded hole(s) in the CI keel. Actually, the use of butyl rubber tape as a sealant under the nuts and washers might not be a bad idea when replacing the studs. This recognizes the fact that the galvanized washer isn't worth the powder to blow it to hell as far as cathodic protection goes.
To simplify matters here, I think the OP should restrict his sailing to the sands of the Sahara, or simlar regions, and eliminate the water intrusion problem at the source
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Boat's on the hard now, just following up. For this season I've picked the 2 worst studs to remove and replace. Not coincidentally, I guess, they are in the deepest part of the bilge.
The PO slathered anti-rust paint on them. (I could write a book, right?) I've brushed most of it off with heat and a wire brush. I'll do the same with the other studs later.
See the photos. The washers and exposed studs are corroded. What's left of the exposed studs' threads are pretty much useless, there's not enough to clean up with a die.
But the nuts are still shiny and, from what I can see, they still grab onto intact thread on the studs.
The other 7 studs are not this far gone, so I'm crossing that bridge next season. This is already nerve-wracking enough.
Next step for these 2 studs: 3-4 hourly doses of heat then penetrating oil. Then drown them overnight in a cozy moat of penetrating oil overnight surrounded by butyl.
Tomorrow will be my first, and ideally successful, attempt to remove the 2 studs.
Plan A: After a hearty breakfast, bite down onto each stud with the biggest vice grip I can fit in this space.
Plan B: Suggestions?
Questions, opinions, and encouragement are welcome.
The PO slathered anti-rust paint on them. (I could write a book, right?) I've brushed most of it off with heat and a wire brush. I'll do the same with the other studs later.
See the photos. The washers and exposed studs are corroded. What's left of the exposed studs' threads are pretty much useless, there's not enough to clean up with a die.
But the nuts are still shiny and, from what I can see, they still grab onto intact thread on the studs.
The other 7 studs are not this far gone, so I'm crossing that bridge next season. This is already nerve-wracking enough.
Next step for these 2 studs: 3-4 hourly doses of heat then penetrating oil. Then drown them overnight in a cozy moat of penetrating oil overnight surrounded by butyl.
Tomorrow will be my first, and ideally successful, attempt to remove the 2 studs.
Plan A: After a hearty breakfast, bite down onto each stud with the biggest vice grip I can fit in this space.
Plan B: Suggestions?
Questions, opinions, and encouragement are welcome.
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I would take a look at the threads under those nuts. The threaded part projecting above the nut does nothing for strength.
If the threads under that nut are in good shape - I'd replace that square washer with a better material, and reassemble.
If the threads under that nut are also compromised - then I'd replace the whole stud.
dj
If the threads under that nut are in good shape - I'd replace that square washer with a better material, and reassemble.
If the threads under that nut are also compromised - then I'd replace the whole stud.
dj
A: If it still has any of the mystery oil on it, it's gonna be too slippery to grap even if you're as strong as Paul Bunyan.
B: Get rid of the round. Grind two sides to get two opposite sides flat(ter). Shouldn't need to take much off to get something better to grip.
Good luck.
B: Get rid of the round. Grind two sides to get two opposite sides flat(ter). Shouldn't need to take much off to get something better to grip.
Good luck.
Can you remove the nice shiny SS nut that the PO f _ _ _ ed up the stud. That was an absolute NO, NO which caused all of that corrosion. Better to use a galvanized nut and replace it every few years as it corrodes.
If possible, use a 8" pipe wrench (and a possible snipe if space permits) as it tightens the grip on the bolt as you torque it. Use the pipe wrench on the solid threads of the studs if you get the SS nuts off.
I'd say once you are finished with the studs and they are installed with plenty of release compound, that sounds like a maintenance job every couple of years when things start to look rusty. Remember, no SS anywhere on this job. If you are replacing studs, make the new ones good and long to get a hold on the stud at the top of the bilge.
If done on a regular basis, the full job shouldn't take you more than an hour.
Cut the bad portion of the bolt off and use an impact driver to loosen the nut.
There are products which will freeze the nut. Try heating and then freezing to free the nut
There are products which will freeze the nut. Try heating and then freezing to free the nut
What has 2 thumbs and is enormously relieved? This guy.
Following @Ralph Johnstone and others' advice, I started with the nut using a socket wrench and a 15-in flex handle. With less leverage than I expected to need from my feet against a bulkhead, the studs came out with no fuss. Overnight penetrating oil and heat ftw.
Lucky me, the nuts had enough thread to keep the keel on, and enough corrosion to overcome the friction of removing the stud.
The photos show that the corrosion was entirely where it didn't affect the integrity of the keel-hull fastening. The threads on the 2 posts that went through the hull and into the keel are pristine. There's some kind of white sealant that covers what looks like red thread loc-like material. Even the washers are fine underneath. The hull's fibreglass around the stud holes is hard and makes a satisfying thunk when tapped with a mallet.
Lucky, lucky, lucky me.
Lucky me, I guess. Yeah, 40 years is way too long but it's evidently a good setup that worked perfectly. I'm expecting the rest of the studs are in similar shape, if not better.
But I'm definitely replacing the whole kit: nuts, washers, studs, and sealant. And I'll be inspecting and re-tightening every couple of years from now on. I'll post comments and photos when that happens.
It's 10:00 am and I need a drink.
Oh, and thanks for the advice!
Following @Ralph Johnstone and others' advice, I started with the nut using a socket wrench and a 15-in flex handle. With less leverage than I expected to need from my feet against a bulkhead, the studs came out with no fuss. Overnight penetrating oil and heat ftw.
Lucky me, the nuts had enough thread to keep the keel on, and enough corrosion to overcome the friction of removing the stud.
The photos show that the corrosion was entirely where it didn't affect the integrity of the keel-hull fastening. The threads on the 2 posts that went through the hull and into the keel are pristine. There's some kind of white sealant that covers what looks like red thread loc-like material. Even the washers are fine underneath. The hull's fibreglass around the stud holes is hard and makes a satisfying thunk when tapped with a mallet.
Lucky, lucky, lucky me.
Lucky me, I guess. Yeah, 40 years is way too long but it's evidently a good setup that worked perfectly. I'm expecting the rest of the studs are in similar shape, if not better.
But I'm definitely replacing the whole kit: nuts, washers, studs, and sealant. And I'll be inspecting and re-tightening every couple of years from now on. I'll post comments and photos when that happens.
It's 10:00 am and I need a drink.
Oh, and thanks for the advice!
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You can't argue with what's worked for some 40 odd years. Looks like the white goop formed an excellent seal against the intrusion of water into the keel threads.
I'd still suggest that you avoid any SS material like the plague when re-assembliing the studs into the keel.
The original metallurgy: cast iron keel, stainless stud, stainless nut, galvanized washer.
Dunno what the original white goop is. I'll be using sikaflex 291. It's my go-to for things like this. It just needs to keep the water out, it's not that difficult to use, and I've trusted it for years.
Are you sure about the stud being SS ? ? ? ? ? ?
If it is, it's the world's worst SS with that much corrosion. My guess would be galvanized steel.
At the risk of repeating myself, no SS within a 10 ft. pole of the studs this time around. Galvanized steel only, keep it dry, and inspect every few years for corrosion.
Do you have a metal recycling center near you? Call around and see if there is one close enough that has a hand held XRF gun - often called a metal analyzer. Take the stud and nut to them and have them see what the base metal actually is. Those studs don't look like stainless to me but it's really hard to tell from the photos.
Instead of guessing - this way you can know what was originally used. I think 40 years is a pretty good indication that whatever they originally used was pretty good metallurgy.
dj
Excellent question and observation. I assumed it's stainless but now you've put doubt in my heart. I'll bring it to my fave local machine shop to confirm.
Thanks!
Place a magnet against it to see if it's SS or mild steel.
The problem with this is if it is magnetic - you don't know what it's made from. If it isn't magnetic then it's likely stainless steel. It not a robust test. However, for sure try a magnet, if it's not magnetic it's stainless. But, if it is magnetic - you still don't know what it actually is.
dj