I'm bottom painting the hull and needs some some sanding then barrier coating and paint but the keel has some surface rust that has penetrated a first layer of steel and I'm not sure what to do there but grind and should i build up with some super strong epoxy and fair out the coating then barrier coats then bottom paint? i would like to torque the keel bolts any particular procedure and ft lb setting i should use?
keel restore 34 hunter
- Thread starter hunter healer
- Start date
Well, I can tell you what was recommended and worked for me. Have the keel sandblasted. After the bottom is power washed clean, take a pry bar and hammer to chisel or cut away any loose material on the keel. Be sure to expose any pockets that might hold water. Use a belt sander with 80 grit paper to sand the keel, exposing as much metal as possible.
I had mine soda blasted, which doesn't do the job, then chipped at the epoxy-paint buildup flaking off the keel. I plasticized the exposed metal surface by coating with OsFro to prevent further rust and provide a good surface for the barrier coat. I used West System Six10, that comes in a caulking tube and is mixed at application with the microballoons already in it, for fairing the leading edge of the keel and some areas along the hull. I used two coats of IP 2000 as the epoxy barrier coat, then painted after the 10 day cure period. Not race quality, but a definite improvement in the material condition.
Good luck.
I had mine soda blasted, which doesn't do the job, then chipped at the epoxy-paint buildup flaking off the keel. I plasticized the exposed metal surface by coating with OsFro to prevent further rust and provide a good surface for the barrier coat. I used West System Six10, that comes in a caulking tube and is mixed at application with the microballoons already in it, for fairing the leading edge of the keel and some areas along the hull. I used two coats of IP 2000 as the epoxy barrier coat, then painted after the 10 day cure period. Not race quality, but a definite improvement in the material condition.
Good luck.
If you thought you bought a lead keel boat you are about to be disappointed! It is iron, cast from scrap iron.
The process Splax describes is the right one- make sure you get everything off and coat with a rust conversion product- something that converts the rust to an inert substance like Feric oxide. Then coat with barrier coat- I put 5 coats of IP2000 on mine and then VC17
The process Splax describes is the right one- make sure you get everything off and coat with a rust conversion product- something that converts the rust to an inert substance like Feric oxide. Then coat with barrier coat- I put 5 coats of IP2000 on mine and then VC17
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Assuming an iron keel, after you've scraped, ground, and maybe sand blasted to remove as much of the rust as possible, you can apply phosphoric acid (OSPHO), which is available cheap in the paint department at Home Depot and others. It's what we use to kill rust on commercial steel boats. Paint the OSPHO on with a chip brush, making sure to dab it into the pits. Let it sit 12 hours (keep it dry), then barrier coat and paint. OSPHO turns iron oxide (rust) onto iron phosphate which is a stable compound that can be painted. Works on rusty cars, too.
Thanks PGIJon- the result of a lot of hours of work (and missed sailing time!). Iron Phosphate is the correct substance -thanks Capt.
Hunter Healer: am going through the process now. Basically same as Splax and others reported. Here are my steps (see attached pix):
1. Power washed at haul out
2. Sandblasted and wire wheeled.
3. Stopped oxidation with Max Cor CF--Awlgrip's non chromate rust inhibitor. Note: not normally to be used below the water line if exposed to water. But mine will be encased in several layers (see below).
4. Two coats of Awlgrip Hullguard (seals the Max Cor)
3. Two layers of fairing (West System) and smoothing.
4. Sanding (phase I'm at now)
5. Epoxy barrier coat
6. Bottom paint (two coats)
lot of work and $, but what's new? Good luck.
1. Power washed at haul out
2. Sandblasted and wire wheeled.
3. Stopped oxidation with Max Cor CF--Awlgrip's non chromate rust inhibitor. Note: not normally to be used below the water line if exposed to water. But mine will be encased in several layers (see below).
4. Two coats of Awlgrip Hullguard (seals the Max Cor)
3. Two layers of fairing (West System) and smoothing.
4. Sanding (phase I'm at now)
5. Epoxy barrier coat
6. Bottom paint (two coats)
lot of work and $, but what's new? Good luck.
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Richard, Yes, bottom looks nice but impressed with reflection on your hull. I'm following Main Sail's buffing protocol but hull is still a bit "splotchy" after the compounding phase (wet sanded with 1000 first). Is your sense that the polish phase will remove that or should I repeat compounding? Sorry no pics. Have to wait now until bottom is sealed.
I used a product called Max Cor CF over the acid washed steel. Max Cor does not contain chromates which have been shown to be toxic and a carcinogen, especially if inhaled. I'm not a chemist but my layman's understanding is Max Cor forms a thin dry layer over the acid washed steel which provides a good adhesion for the next overcoat. I assume if not over coated it would be water soluble. I gotta believe there are some chemists on the forum than can provide a better scientific explanation.
I shortcut Maine's method a bit- used compound, then finesse, then wax. I would try a patch with the Finesse first before another compounding, it may take out the splotchy spots.
In the sense that they are both primers and both form a paintable bond with the keel. But I believe Ospho contains chromates while Max Cor CF says it does not.
Keel Restore
I had the same problem on my 33.5 when I purchased her. The keel had flakes of steel coming off. I spent 2 weekends with a grinder clearing off the rust, then cleaned the keel as well as I possibly could with alcohol. I rough sanded with 80 grit on a disk sander, cleaned again with acetone, applied 4 coats of interlux 2000. After the epoxy hardened, I scuffed the surface with 100 grit (orbital sander) and applied 2 coats of Interlux primecon, then 2 coats of West Marine CPFF bottom paint. I hauled the boat 2 years later and had a spot about the size of a quarter that needed to be touched up. I did not fair the keel, it was left with all the dimples and stuff - since the boat was over 20 years old.
I had the same problem on my 33.5 when I purchased her. The keel had flakes of steel coming off. I spent 2 weekends with a grinder clearing off the rust, then cleaned the keel as well as I possibly could with alcohol. I rough sanded with 80 grit on a disk sander, cleaned again with acetone, applied 4 coats of interlux 2000. After the epoxy hardened, I scuffed the surface with 100 grit (orbital sander) and applied 2 coats of Interlux primecon, then 2 coats of West Marine CPFF bottom paint. I hauled the boat 2 years later and had a spot about the size of a quarter that needed to be touched up. I did not fair the keel, it was left with all the dimples and stuff - since the boat was over 20 years old.