Keel refinishing

[Ken Cross]

Hi all
I've finally pulled the trigger on buying a 1989 Hunter 30.
The surveyor suggested taking the keel down to bare metal. Prime, barrier coat, then bottom paint. It's a steel keel (at least it's magnetic) and has some areas of rust color. so far it appears to be just superficial. He suggested "use an 80 grit soft pad".

What would you do?

I'm still not sure what he has in mind when he says "Soft Pad" but I plan to ask.
My idea is to minimize the maintenance I need to perform in the future. I still need to pull it out soon for bottom paint, but I won't have possession of it until next week.
Ken

 

[Ken Cross]

Oops, I forgot to post the photo
Ken

 

[splax]

Keel maintenance

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.

 

[Brian S]

If it's a cast iron keel, I know a guy re-doing his swing keel over on www.trailersailers.com. His recommendation is to get all rust off, whether by sandblasting or needle gun or whatever, down to bare metal and also getting into any pockets where there are rust pits. Then, coat with phosphoric acid, to create rust barrier layer of iron phosphate. Then coat with several coats of coal tar epoxy. After that, fill and fair using a fairing product designed to be used below the waterline. (There are such products available from fiberglass places.) If you burn through to metal while sanding, re-phosphate, re-coal tar that area. Once it's faired to your satisfaction, 3 or so more coats of coal tar epoxy, and then paint.

When he did the keel 15 years ago, he put Marine Tex on as a fairing compound, BEFORE he did the CTE, thinking the Marine Tex would adhere and the CTE would seal it in. In areas where the CTE went directly on phosphate/metal, there was no rust at all. In areas where the CTE went on the Marine Tex, water got under the Marine Tex, and rusted all to hell. Hence his new procedure outlined above.

For those who haven't heard of CTE, it's widely used commercially, to coat steel navigation buoys, barges, tugboats, and the like.

 

[Richard Bryer]

I set out to do this job including the whole hull ,a year ago this past summer. Initial plan was to soda blast the whole thing. Splax is right, soda blasting is not the best choice. My contractor turned out not to have a big enough compressor to do the job. We went to a needle gun. Did the job but took a while. I immediately coated it with a rust converter, then a coat of IP 2000. Then faired with an epoxy fairing compound then 4 more coats of IP2000. Use different colours if you can as it is easier to tell where you have been.
Keel had a couple of very small spots when I hauled out fall before last- dremeled them out and filled with the fairing compound. No spots this year when hauled out in Oct. This is what it looked like when launched after the work.

 

[Scott T-Bird]

RB, what a great looking boat and nice job! Ken, enjoy the new boat. She makes the upgrade look worthwhile!

 

[Ken Cross]

Wow, Thanks everyone. I have no previous experience on this one. Now I need to wait, wait, wait, wait for closing. We don't have possession of her yet.
Ken

 

[BigEasy]

I bought a 1988 Hunter 33.5 about 17 years ago. Had the same keel as your 30. The pre purchase survey noted rust on the keel; the surveyor advised stripping it down to bare metal and coating with Coal Tar Epoxy. I just spot treated the keel and three years later, had it sand blasted to bare metal. We primed it IMMEDIATELY with an interlux primer after blasting, then filled and faired, reprimed and top coated with an interlux metal paint. It lasted for five years without further rusting---eventually lost the boat in hurricane Katrina.
The Beneteau that I currently own is seven years old and has some areas of rust that is breaking thru. On last years haulout, I wire brushed & sanded the spots to bare metal and coated with interlux 2000 epoxy. If the problem gets worse I will eventually have it sand blasted and coat with a few applications of 2000 epoxy. I believe that most individuals & manufacturers are now using some sort of epoxy to encapsulate.

 

[bffatcat]

REFINISHING AN iRON KEEL

Ive had my boat 15 years now. about 4 years ago the keel was pretty rusty quite a bit of the original fiberglass coating was falling off. I peeled the rest of the old coating off, which was not to difficult most of it just fell off. After the keel was down to bare metal I washed it with lacquer thinner applied two coats of pettit single part rust inhibitor. Next came 2 coats of west system barrier coat and finally 2 coats of ablative bottom paint I di nothing else. After 4 seasons in salt water there is no rust on my keel

 

[IH82BL8]

Hey Fatcat,

I'm glad to hear yours is holding up well, I did this project in 2013 and will haul the boat again in a couple of months to see how it looks.

My H31 has an external cast iron keel. Whatever was on it peeled of in sheets leaving the iron exposed. I cleaned it using a die grinder with a wire wheel attachment. The folks at WM recommended what to put on it next--I don't remember what it was.

 

[BigEasy]

One thing about sand blasting vs other rust removal methods, I think that blasting is the preferred method. When the blasting was completed in 30 to 45 minutes, the cast iron was bright & shiny without a trace of paint or rust remaining----it looked like a new keel. The yard emphasized that the primer needed to be placed immediately after blasting because oxidation starts immediately. Don't know what it would cost today to have a keel sandblasted; however, I do believe that you will get a better & longer lasting result.

 

[woodster]

Key word here is sand for metal. Soda for Frp

 

[wufibugs]

what about blasting, fairing and POR 15? I'm not sure if you can paint over POR 15, though.

 

[Charlie98117]

The cast iron keels are a typical problem area on Hunters. The PO on mine fought it over the 30 years they owned the boat. Before selling to me they had it ground to bare metal and epoxy coated. 9 months later at the survey there were a couple a small rust spots showing already. The PO called the place that did the work and they agreed to fix it for free so I'm good for now, we'll see what it looks like next haulout.

I bought the boat knowing this to be a problem area but think it's not that bad considering all boats have maintenance issues to deal with. And after a season sailing her I think a little bit of keel work once in a while is far outweighed by all the positive aspects.

 

[bffatcat]

for charlie

A little bit of keel work is one thing. The entire coating falling off is another. read my other post on this thread