I've got a 1992 model 33.5 with a cast iron wing keel. Its showing corrosion in some spots and needs servicing. Would like any suggestions for approaches and products. My current thinking is to gring down to bare metal, fill in the corroded bits, re-seal, and repaint. Thanks
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Barrier coat it.
Dan: I would do exactly what you are doing. Take her down to bare metal, fill pits, prime, coat with recommended amount of VC Tar barrier coat and then regular bottom paint. Be sure that the primer and the barrier coat is compatible.
Dan: I would do exactly what you are doing. Take her down to bare metal, fill pits, prime, coat with recommended amount of VC Tar barrier coat and then regular bottom paint. Be sure that the primer and the barrier coat is compatible.
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Doug B
barrier coat good advice.....plus...
We have 33.5 that had same problem. Please be aware of the following. 1) wipe it well after grinding with solvent to remove all dust. 2) grind pits first and area immediately around pits. We used dremel. You only have 12 hours or so to get the barrier coat on once you grind. It will oxidize in the air that quickly. Less time is better. Overfill pits so that when you grind the rest it will level them off for final fairing and painting. 3) It is probably galvanic corrosion. Make sure you have a wire leading from keel bolt to engine (or better yet to a "shaft brush", west marine has a good one). That way your zincs will get it not your keel next time. If you leave plugged into shore power often, look into getting a galvanic isolator (pretty cheap and installs in about an hour) to help with corrosion. While your at it, connect a bolt from your external shaft strut (you can get to under aft berth) to the shaft brush too. 4) we used interlux 2000 (?) barier coat. Dont be stingy get on several (4-5 at least) thick coats. 5) Ask your boatyard if they can leave it in the sling overnite so you can get underneath keel to grind out and repair the bottom too. Ours was the worst there. Have fun.
We have 33.5 that had same problem. Please be aware of the following. 1) wipe it well after grinding with solvent to remove all dust. 2) grind pits first and area immediately around pits. We used dremel. You only have 12 hours or so to get the barrier coat on once you grind. It will oxidize in the air that quickly. Less time is better. Overfill pits so that when you grind the rest it will level them off for final fairing and painting. 3) It is probably galvanic corrosion. Make sure you have a wire leading from keel bolt to engine (or better yet to a "shaft brush", west marine has a good one). That way your zincs will get it not your keel next time. If you leave plugged into shore power often, look into getting a galvanic isolator (pretty cheap and installs in about an hour) to help with corrosion. While your at it, connect a bolt from your external shaft strut (you can get to under aft berth) to the shaft brush too. 4) we used interlux 2000 (?) barier coat. Dont be stingy get on several (4-5 at least) thick coats. 5) Ask your boatyard if they can leave it in the sling overnite so you can get underneath keel to grind out and repair the bottom too. Ours was the worst there. Have fun.
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Barry
Rust Never Sleeps
You can slow it down, it never goes away. I stripped the iron keel on my h34 and immediately coated it with several coats of VC Tar. Rust was back in two years. Second try - stripped it again and coated it with 2 coats of Petit "Rustlok". Rust was back at the end of the season and this is in fresh water. Next attempt will be sandblast and coat with West expoxy before I head to salt water. They say it important to coat them within a few hours after they are stripped. Glad I can't see the bottom when I'm sailing. Next boat won't haqve iron. Barry s/v "PER DIEM too"
You can slow it down, it never goes away. I stripped the iron keel on my h34 and immediately coated it with several coats of VC Tar. Rust was back in two years. Second try - stripped it again and coated it with 2 coats of Petit "Rustlok". Rust was back at the end of the season and this is in fresh water. Next attempt will be sandblast and coat with West expoxy before I head to salt water. They say it important to coat them within a few hours after they are stripped. Glad I can't see the bottom when I'm sailing. Next boat won't haqve iron. Barry s/v "PER DIEM too"
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Jay Hill
I'm with Barry
Recent bottom job on H31 included complete strip/grind/repair/fill/sand and EPOXY of entire vertical surfaces of iron keel. Didn't want to do the bottom of the keel as I still need lightning ground and I don't have a plate. To reduce the rust on the bottom from getting under the epoxy (if possible) a small groove (1/8") was cut in the edge of the keel corner (corner between vertical edge and bottom) and cleaned thoroughly. All vertical surfaces were coated with 1/8" epoxy along with the cut edge and the keel/hull joint. It's only 6 months old though, so I'll have to let you know HOW it works in a couple of years. Lotta good that does you now, huh?
Recent bottom job on H31 included complete strip/grind/repair/fill/sand and EPOXY of entire vertical surfaces of iron keel. Didn't want to do the bottom of the keel as I still need lightning ground and I don't have a plate. To reduce the rust on the bottom from getting under the epoxy (if possible) a small groove (1/8") was cut in the edge of the keel corner (corner between vertical edge and bottom) and cleaned thoroughly. All vertical surfaces were coated with 1/8" epoxy along with the cut edge and the keel/hull joint. It's only 6 months old though, so I'll have to let you know HOW it works in a couple of years. Lotta good that does you now, huh?
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steve zorn
curious
Which Marblehead U.S. are you located? Fresh water or salt water? It in Ohio I think I am in marina next to you and cured same problem with responses you already received.
Which Marblehead U.S. are you located? Fresh water or salt water? It in Ohio I think I am in marina next to you and cured same problem with responses you already received.
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Jim McCue
Another product
I have had some "freckles" too. I braise 'em down, then paint it with "Extend" ( a rust inhibitor) which turns black , dries rather quickly then I give it a couple dab coats of CSC antifouling. This has worked pretty good. Find Extend at auto stores. I use it on my stoop wrought iron railings. J. McCue
I have had some "freckles" too. I braise 'em down, then paint it with "Extend" ( a rust inhibitor) which turns black , dries rather quickly then I give it a couple dab coats of CSC antifouling. This has worked pretty good. Find Extend at auto stores. I use it on my stoop wrought iron railings. J. McCue
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Dan Grosz
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Dave Swanson
Is it Galvanic???
I have a 1989 Hunter 30 and have had the same problems with the keel blistering every two years or so and it is an expensive repair. Could it be that this corrossion is galvanic and caused by installation of too much zinc? I typically have two zincs on my propellor shaft. I am looking for a way to reduce the amount of expensive keel blistering. We always have the keel sandblasted and immediately epoxy coated prior to oxidation. Anybody have an opinion on this?
I have a 1989 Hunter 30 and have had the same problems with the keel blistering every two years or so and it is an expensive repair. Could it be that this corrossion is galvanic and caused by installation of too much zinc? I typically have two zincs on my propellor shaft. I am looking for a way to reduce the amount of expensive keel blistering. We always have the keel sandblasted and immediately epoxy coated prior to oxidation. Anybody have an opinion on this?
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