Removing Corroded Seacocks and Thru-Hulls

[Reefmagnet]

Originally Posted by Maine Sail

Ditto! Have removed a lot of them in this fashion. Minimal to no damage to the fiberglass too..

Same here. 36 grit flap disk on a 4" grinder makes it easy as and takes no more then a couple of minutes for each fitting.

[Reefmagnet]

Originally Posted by nautical62

Thanks for the informative post. I'm curious as to how people fill old holes that they won't be putting another through hull through.

For a solid hull (no experience with cored) I've used the same angle grinder/disk combo as described above to grind the outside of the hull with a suitable bevel then laid in heaps of epoxy and cloth in progressively larger sections (it's kind of like filling the inside of a cone) until its brought flush with the hull. To keep shape on the inside I wedge (or use gravity) a piece of wood over the hole shaped to the inside curvature wrapped in plastic food wrap to stop the epoxy sticking to it.

Once set I've ground and faired. When antifouled / painted over you would never the original hole was there.

[smurphny]

Wow, those are really "pink"--lots of electrolysis. Good thing you replaced them. Were you able to free them up once you had them out? Usually a little heat will release them. Often, the inside part is still perfectly ok, if a little green, and it's just the mushroom that needs replacing. Didn't read the whole thread but if no one mentioned it, don't be tempted to use plumbing ball valves as some do to save money. They are not adequate and are made from different alloys than marine parts.

[GordMay]

Originally Posted by nautical62

Thanks for the informative post. I'm curious as to how people fill old holes that they won't be putting another through hull through.

Goto page 43 - 44
➥ http://www.westsystem.com/ss/assets/...aintenance.pdf

And ➥ http://www.goodoldboat.org/pdfs/Addi...inyourboat.pdf

Or ➥ Through Hole Plug / Repair

[Cptn Happy]

After many months of anguishing over this project, I just finished replacing six thru hulls and sea cocks on my boat. They were the old-style Groco's w/the rubberized rotating cylinders. The problem seems to be if not serviced regularly the rubber surface sticks to the interior of the body of the seacock. When you try to muscle the handle to open/close the valve you break the handle loose from the face of the end of the cylinder. It cannot be reattached, i.e. you're screwed! Groco has very few replacement parts and they aren't making any new ones. Thus the decision to replace them. They had done a good job for twenty-some years so decided to stay w/Groco. In addition, their tech service was very helpful. Now, here's the secret for easily removing these babies, which are usually slathered in 5200: buy yourself a "step wrench" to remove the thru hulls. Once they are out the seacock is easy-just break it free from 5200. I got my wrench from Hamilton Marine-approx $35 plus. It is essentially a graduated size cylinder w/a groove on each side. They catch the two "ears" on the inside of thru hull. A pipe wrench can be applied to the base to turn the step wrench which for me broke the thru hull free and allowed me to unscrew them from the seacock. I couldn't believe how easy it was!! I too had read about folks grinding off the heads, sawing them off, etc. I was distressed-although I'm pretty proficient w/my 4" grinder. Forget it-get a step wrench! Additional tip. Once you clean all the old 5200 off of the backing plates recoat them w/epoxy before applying fresh 5200, Sikaflex, etc. Will try to post some pics I took of finished project. Cptn Happy

[Ziggy]

Originally Posted by Cptn Happy

Now, here's the secret for easily removing these babies, which are usually slathered in 5200: buy yourself a "step wrench" to remove the thru hulls. Once they are out the seacock is easy-just break it free from 5200. I got my wrench from Hamilton Marine-approx $35 plus. It is essentially a graduated size cylinder w/a groove on each side. They catch the two "ears" on the inside of thru hull. A pipe wrench can be applied to the base to turn the step wrench which for me broke the thru hull free and allowed me to unscrew them from the seacock.

It's great the step wrench worked for you. But the dogs in the newer Groco thru-hulls can be very easily sheared off when the step wrench is torqued with more force than possible by hand. I found out the hard way when tightening it, and when I brought the broken thruhull back to Hamilton, they refused to exchange it. In fact the Groco catalog warns not to use the tool to remove old thru hulls!

[Cptn Happy]

Couple pics attached-I think. Re breaking off the "ears" inside the thru hulls by tightening them w/a step wrench, that certainly wouldn't intill much confidence in the quality of the cast bronze thru hull. I hope I didn't just get lucky.

[minaret]

The step wrench is how we usually do it in our yard, unless destructive methods are required, in which case a 4" grinder is the quick answer. For me the secret has always been one guy on the outside with the step wrench and one guy on the inside with a MAP gas torch. Heat the interior of the fitting up until spit sizzles when you spit on it. This will simultaneously melt the 5200 and cause the female threads to expand. Get it nice and hot and usually you can get even badly seized ones off by hand from the inside, or using a Ford wrench. Then you put grease on the threads to preserve 'em and take them to the sand blasting box to clean up. As long as they're not too pink they come out like new. I've saved lot's of owners some money on new thru-hulls over the years like that. Once you've got them all dissassembled they're usually easy to rebuild. Of course the OP's looked beyond redemption...