Coating a cast iron keel?

Manureva · Nov 24, 2013

I used interprotect, last year keel is still good as new after one season

Squidd · Nov 24, 2013

It's all in the prep anyway..

DougM · Nov 24, 2013

Did my keel with Interprotect last Spring. It's vitally important that the preparation is done properly. The surface has to be ground down to bare iron (or media blasted),and the first coat of Interprotect must be done before any oxidation appears no matter how slight. Its a bear to get the old coating off. Multiple coats of Interprotect need to go on within hours of one another, and the first coat of bottom paint has to follow while the last coat of Interprotect is still a bit tacky. It's not a one day and done type of job.

Captn TJ · Nov 24, 2013

DougM said:
Did my keel with Interprotect last Spring. It's vitally important that the preparation is done properly. The surface has to be ground down to bare iron (or media blasted),and the first coat of Interprotect must be done before any oxidation appears no matter how slight. Its a bear to get the old coating off. Multiple coats of Interprotect need to go on within hours of one another, and the first coat of bottom paint has to follow while the last coat of Interprotect is still a bit tacky. It's not a one day and done type of job.

Success is not only determined by bright metal but coating it almost immediately with a primer. I believe the primer interlux uses is primocon (sp?)

I have successfully done my keel in 'patches' vs a complete keel. So far so good

Captn TJ · Nov 24, 2013

a65sailor said:
I plan to have the keel blasted clean in the spring and get the epoxy coating on right away. You are all correct that prep is very important. Thank you for your comments. It sounds like the Interlux products are widely used. I would really like to know the difference in the two epoxy products. Thanks.

There is also a product called VC-tar. Both yards I've been in use Interlux exclusively.

DougM · Nov 24, 2013

I have used primocon for a temporary patch job and it does a remarkably good job. When I redid the keel completely, that was the most difficult portion of the removal process. I've got to say its at least a good stopgap.

Charlie Jones s/v Tehani · Nov 24, 2013

I've had two boats with cast iron keels, and have had very good luck with Coal Tar epoxy. It's used on the offshore rigs, and by the CG on buoys.

Stinks while being applied, but has held up very well. I used the Interprotect 2000 on the hull , but not the keel. Just redid the bottom after several years (6 on the keel) with almost zero problem on the keel.

patrick33308 · Nov 25, 2013

Good post by a65Sailor, very timely...............

saildog · Nov 25, 2013

I have the Hunter 34 too and i used VC Tar and that was 3 years ago. It has held up very well and is self leveling, so it came out very smooth as well. This is the second cast iron keel I have done with VC Tar and both are still looking good and free of rust. Surface prep is everything! I put 4 coats of VC Tar on. The last coat was coated with good bottom paint(Super Ship Bottom) while still tacky. I'm in SW Florida in some of the saltiest water on earth.

Scotian · Nov 25, 2013

If there are only a few rust spots..like mine...I gave a test using rustomlium paint.. Covered this with undercoat.. Looked good after a season

Barnacle Bill · Nov 25, 2013

I don't think V C Tar is available anymore. Interprotect 2000 is much better as you can put on more than one coat in a day. Time between coats depends on the ambient temperature. It is explained in their product info.

bffatcat · Nov 26, 2013

cast Iron keels

Im sure there number are a number of systems that will work. What I did was : first I scraped off what was left of the original fiberglass coating on the keel. next I washed the keel with lacquer thinner to remove any residue. Then 2 coats of pettit 1 part rust inhibitor next was 2 coats of west system epoxy. and finally 2 coats of ablative bottom paint. after a season in the water things are looking good. Dont forget its in the prepwork

jibes138 · Nov 27, 2013

have a lead keel but over ten years ago ground to bare lead mostly with a belt sander. sand again immediately before coating to remove any oxidation (lead is very reactive and will oxidize almost immediately). Then 2 coats of West system epoxy. Then two coats of interprotect 2000 as a base for the paint. Then while tacky apply the paint. Haven't had any paint peeling issues on the keel since. Boat is out of the water now for a paint job and it still looks good.

IH82BL8 · Nov 30, 2013

I did this job a few months ago. I scraped off the old paint; an easy job since it was peeling off in sheets anyway. I cleaned the keel using a compressor and die grinder with a wire wheel. Not nearly as messy as blasting.

zeehag · Nov 30, 2013

i learned that my iron keel was perfect after 26 yrs unprotected and no haulouts.
once i hauled it, i figgered, ok was good since 26 yrs , lets leave it. when i hauled to place into hank mckunes yard(--he built it--took it in trade against my yorktown 42 i was having him build in 1990....) we found an inch was rusted...one inch everywhere, allover keel. it lost one inch of iron to being unprotected. (one inch from each side, as well as from leading and trailing edges, etc...)
if i were you, after this experience of my own boat, i would find a nice barrier coat for iron keels and use it. enjoy your boat.