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Swing Keel Job - All or Nothing?

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LeighMarie
Navigator

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USA
188 Posts

Initially Posted - 04/05/2004 : 20:39:46

I have been obsessing all winter about my swing keel! I finally got the boat out of storage and it's in my driveway. When I look at the keel, I see some rust, and the anti-fouling needs to be redone. Does it have to be all or nothing? I can't imagine not doing anything to it. But, if I do anything do I have to bring it all the way down to the bare metal? And, does it have to be done with a grinder or by sandblasting? I went to Lowe's and he sold me a 40 grit 6" sandpaper pad that I put on my drill. It did alright for the 10 minutes I worked on it, but there are "pock-marks" that it wouldn't get to. If I then covered these over without doing anything more would they rust?

My brother is willing to come and sandblast it, but I will have to rent a sandblaster, but a "ton of sand!" he said, and then will have the sand all over. Would it be easier to rent a grinder to do it? Or is this job just too big to do correctly. But then, if I don't do it down to the metal can I just cover it with anti-fouling and just pretend the rust isn't there?

Also, I bought the Interlux 353/354 combo that has to be mixed with the 355 solvent, and I have the Interprotect, but the cans say the temps need to be at least 50 degrees. It's supposed to be a balmy 45 degrees this weekend!

I do have Thursday and Friday off also and I could work on it with a grinder, but the pamphlets say that within an hour of exposing the bare metal I have to have it covered. What if it's longer? Does the keel fall apart? Couldn't I just give it a once-over before actually coating it? I have to imagine it's going to take me longer than an hour to do the whole keel! (My wife suggested I just paint over it and sell the boat. That way the problem just goes away!)

What do I do?

Dave & Sharon on "Leigh-Marie"
Hull #5128

Edited by - on

OJ
Master Marine Consultant

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USA
4382 Posts

Response Posted - 04/05/2004 : 21:42:58

If you're going to go through the motions of sandblasting you want to be thorough of course. The challenge here is getting the top portion of the keel while the boat is on the trailer (as you know there <i>are</i> methods for achieving this.) BTW, you'd obtain much better results using less material by employing a pressurized blasting pot as opposed to say, a Craftsman home workshop sandblaster.
The ideal solution would be to locate a blasting facility the has industrial grade equipment that can clean the keel in ten or twenty minutes and apply a coating of your choice - all in the same visit.
One company I know of uses plastic bead shot - separating the beads from the waste, recycling them several times over.
Those would be my "ALL" remedies.

Edited by - on

Frank Hopper
Past Commodore

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Pitcairn Island
6776 Posts

Response Posted - 04/05/2004 : 21:45:07

Have you considered a heat gun?

With baking soda you have very little mess

http://homepage.mac.com/fhopper/iMovieTheater34.html

http://homepage.mac.com/fhopper/PhotoAlbum33.html

You do need to do something to the bare metal even if it is just a can of Rustoleum.

Edited by - on

LeighMarie
Navigator

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USA
188 Posts

Response Posted - 04/05/2004 : 21:46:16

This is a picture of my keel.

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ClamBeach
Master Marine Consultant

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3072 Posts

Response Posted - 04/05/2004 : 23:45:59

I'd just take the spots down with an angle grinder (you can buy one for $50.... handy to have around) put some galvanizing primer on followed by a couple coats of derusto and call it good. You'll have to repeat in a few years.

Other than that, drop the keel, sandblast to bare metal, use marine rust-converter/sealer and epoxy coat the whole thing.

Take your pick ! Around the ocean, nothing lasts forever!

Edited by - on

Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 04/06/2004 : 01:32:54

Dave & Sharon,

Here's a rerun of a message I've posted before in response to a similar inquiry. I hope you find it helpful. Let us know if you have additional questions.

I've reconditioned two iron swing keels so far. The first was for a Venture 22, the most recent my 1979 Catalina 25. Here's what I did to them:

Forget grinding down the rust as a viable permanent solution. It's a waste of time and effort. There's no way to grind down into all the pits, and any remaining rust will spread like cancer. Sandblasting is what works. After removing the keel from boat, I had it sandblasted to "bright" metal. This is so not fun that I cheerfully paid someone else to do it, even though I own a sandblaster and two compressors. This vital step is a huge amount of work by anyone's definition of the word. Don't underestimate it. And don't even think about quick and dirty compromises at the rust removal stage. Getting rid of absolutely all the rust is key to only having to do this job once.

As soon as I got the keel back from blasting, I etched it with hydrochloric acid (a.k.a. industrial strength toilet bowl cleaner - be careful!) to remove the rust remaining in tiny pores, and the rapidly occurring surface oxidation. I then rinsed it with lots of water, and treated it with two applications of phosphoric acid (a.k.a. "Ospho"). After that was thoroughly dry, I used a stiff nylon scrub brush to remove any dusty residue. Keep a garden hose handy when working with strong acids. Don't let acid spills remain on concrete that you care about. Don't wear clothes that you care about for any of this work.

Next, I applied two coats of WEST epoxy. Then I made up fairing putty from WEST with (#407?) filler additives, and rough faired the keel.

After rough fairing, I wrapped the keel in two layers of 14oz. fiberglass cloth and WEST epoxy to protect it from misc. abrasion in the future. At this point I also added a bronze shoe where the keel runs aground, and piled on several more layers of cloth and epoxy in that area, and along the leading edge. It's vital to bury the entire surface of the cast iron under epoxy prevent rust from getting a foothold again.

I did another round of final fairing on top of the fiberglass (with #410? filler additives), followed by several last coats of epoxy resin as a barrier to protect the soft fairing compound from future bottom paint sanding.

I then applied ablative copolymer bottom paint and reinstalled the keel.

<b>Regarding the pivot bushing issue.</b>

On the Venture keel, I put a greased wooden dowel inside a thin-wall hard rubber sleeve (to keep it straight), taped the sleeve in position in the keel hole, and poured reinforced WEST epoxy resin around it. After the epoxy cured, I drove out the dowel, and left the sleeve in as a bushing. (That's a much lighter keel than a Catalina 25, and the head of the keel trunk is intended to provide more side thrust support.)

In the case of the Catalina 25 keel, I installed a bronze bushing (1"ID, 1-1/2" OD, 1/4" longer than keel thickness).

I got my C-25 bushing from the local marina that did the sandblasting, Banana River Marine Service, Merritt Island, Florida. I'd expect that any bearing house would have catalogs of bushings to choose from. There's not necessarily one correct bushing. Rather, you'll need to evaluate the condition or your keel's pivot hole after sandblasting to determine what outside diameter bushing you need, and are prepared to enlarge the keel hole enough for.

Obviously, if you can't find exactly the bushing you're looking for, get one with too much metal, and have it machined down to fit. Worst case, a chunk cut from the end of a really big damaged bronze prop shaft out of a motor yacht could easily be machined to fit on a lathe. I had a machinist set the pin-to-bushing clearance at about 0.025" to 0.030".

The original 1.0" hole in my C-25 keel was worn and rusted in a jagged hourglass shape, just under 1.5" at the waist, and around 2.0" at the widest.

After the flat sided head area of the keel was faired, I used that surface as an alignment reference. Using a hand-held die grinder (heavy duty version of a Dremel), I ground the narrow center area of the hole into alignment. That was the only area where the bushing touched the walls of the worn hole. I made up a wooden alignment jig (using scrap plywood & 2x4 bored in a drillpress) to hold the pivot pin and bushing straight in the hole. After roughing up the outside of the bushing and the inside of the hole, I cast the bushing in place with WEST epoxy reinforced with powdered aluminum and milled fiberglass lint. I used duct tape dams to form pouring funnels, and to contain the epoxy while it hardened.

After the C-25 keel was installed in the hull, I measured the alignment. At a point 7 feet from the pivot, it was within +/-3/16" of dead straight in the keel trunk. I was grinning.

This repair has now been in service for several years. I can say with confidence that the keel has been reliable, quiet, and trouble free. If there can be a good side to all this work, it's that if you do it right, you don't have to do it again.

Good luck with whatever method you decide to use.

-- Leon Sisson

Edited by - on

svmoxie
Past Commodore

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USA
331 Posts

Response Posted - 04/06/2004 : 06:13:36

Hi Dave,

I feel your pain!

Here are my thoughts. In order to sandblast effectively you need to remove the entire keel from the boat. This is not difficult to do but it is time consuming and you need some fairly significant planning and equipment. (Kind of like building the Pyramids.)

Your keel doesn't look to be in too bad a condition. I would suggest that you consider the "OK for Now" approach instead of the "ALL" or the "Nothing" approach.

Buy, rent or borrow a Random Orbital sander, load it up with 60 grit paper and rough sand the entire keel that you can get to. (crank the keel all of the way up to get the leading edge and then lower it back to the trailer to get the trailing edge. Sand by hand the areas that you can't reach with the sander. You are just cleaning the paint and prepping it for a new coat.

Then get a sheet of plastic, heavy 4 mil, to drape over the trailer and pour, carefully some Muratic Acid over the rust areas and then treat with Ospho a la Leon's post. After that is dry prime with a rust converting primer like POR-15 (http://www.por15.com) or even Rustoleum has one. Then top coat with the same type of bottom paint that you used before. Treat the rest of the hull to the same sanding and then paint. All of that dried slime will blast off with the sander.

If you can, let a yard hoist the boat to launch which will give you a chance to fully lower the keel and apply bottom paint to the trunk and as much of the head of the keel as possible as well as the areas where the trailer rollers are. Otherwise you will need to raise the boat on the trailer to paint those areas. Be sure to follow the product recommendations for temperature ranges, it will make a difference.

This really isn't a huge problem and you will be fine with "just painting it." You WILL have to do it again next year but you can do that for years before the rust gets to the point that you have to do more. But then it will be a huge PITA to fix.

You might want to go this route now and plan to remove it this fall and do the "All" approach over the winter. When you do, pay someone else to sandblast for you, it will be money well spent!

Save or return the Viny-Lux as it would be a waste of product to use it in this situation.

Replace the cable and turning ball / pin while you are there!!

And wear a respirator, not a dust shield, when you work!

Photo credit: Mark Maxwell

Edited by - on

Steve Milby
Past Commodore

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USA
5913 Posts

Response Posted - 04/06/2004 : 09:32:04

I agree with Clif. Looking at the photo, you only have a little rust around the lower end of the keel, and it doesn't justify doing the major sandblasting job. I consider that job appropriate when the surface of the keel is extremely rough and rust is pervasive. Your keel isn't anywhere near that condition.

I would just sand the keel overall with an orbital sander and 60 grit paper. I put a wire brush attachment in my drill, and wire brush any bare metal. Don't sand any deeper than you absolutely have to. Most of the surface of your keel is sound, and it could stay that way for a long time if you don't grind through the protective layers that are presently on it. Immediately after sanding, spray about 3 coats of rust reformer over the places where the bare metal shows through. Then I would put about 2-3 coats of VC Tar over the part of the keel where the metal was bare. Finally, paint the entire keel with bottom paint.

Check it next year, and, if the condition of the keel is still pretty good (which is likely), do the same. If the condition of the keel is getting really bad, you should consider doing the whole sandblasting treatment.

Edited by - on

LeighMarie
Navigator

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USA
188 Posts

Response Posted - 04/06/2004 : 14:44:07

Great ideas, guys. I also think it is not really that bad yet, so I think I will go the route of the "OK for Now." I really, really don't want to take the keel off the boat. And to do it in the right way would probably necessitate that. But, my rust I think at this point is only aesthetic and not extreme at all. I have accomplished so many other tasks on the boat already this year (new internal outhaul system, new pinrails inside, replaced head hoses, rebeddd chain plates, have to install deck organizers and 2 triple rope clutches yet) that the job of doing the keel all the way down to metal will just have to wait until another year. Can't have all the fun in just one year!

Thanks again for your help!

Edited by - on

mroettersr
Navigator

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USA
148 Posts

Response Posted - 04/07/2004 : 00:48:25

Dave,
Since I assume you sail in fresh water, I agree that your keel doesn't look that bad and shouldn't get appreciably worse with some normal annual care. One thing I noticed is that adding zincs to my keel improved the year to year condition of the keel. I did clean up some spots and touched them up with West System Epoxy which has held up very well. I didn't go to the trouble of using an acid wash, etc. as I was anxious to get the bottom wet and the spots look good after a couple years. Hope you have a great season.

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