We went through this process this past spring. We hired a contractor to soda-blast off the 20+ years of bottom paint on our 1989 Catalina 34. We expected to find a barrier coat underneath but found only gelcoat and several dozen tiny blisters at just below the waterline that were concentrated in the middle of the boat (from bow to stern). Apparently, Catalina shipped the boats without a barrier coat and it was put on by the dealer only if requested by the customer. We opened several of the blisters up and found them to be dry. We filled the open blisters with Interlux "Watertight" filler and sanded off the rest. We applied four coats of the Pettit Protect, an epoxy barrier coat, followed by two coats of Pettit SR-21. It looked great when it was done but it was a much more difficult job than we anticipated and made much more complicated by the cold, wet weather we had in Wisconsin this past spring.
Have you exposed your gel coat?
- Thread starter PSR
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I was bass ackwards ...It is indeed Never put Poly on top of Epoxy. Bad combo the other way is okay as they said above.
I had my bottom peeled soon after I bought my O'day 35. After much sanding we applied 11 coats of vinyl ester resin and two or three coats of sandable vinyl ester resin for fairing. Three coats of ablative bottom paint finished it off. The bottom just finished its fifth year and is not showing any signs of blistering. I agree with jibes, there is no reason to apply gelcoat over the bottom once it has been removed. My research suggested that vinyl ester is less porous than polyester resin. Epoxy is probably the least porous but it may be too brittle for large areas.
Thanks for all the thoughts and tales of gel coat and epoxy--very interesting and quite challenging. I've already admitted my ignorance and that I am just following my experienced marine service guys. As in most things, there are differing opinions. Here's a link to another forum where I found a good discussion of gel coat/epoxy interaction starting out with quotation from Bruce Niederer, Technical Services, West System Inc., regarding gel coat bonding to epoxy.
In answer to the question of why not just use epoxy without gel coat, my guys say there are two factors. First epoxy--especially good epoxy like West System--is quite expensive compared to gel coat. Second, and more importantly IMO, epoxy is so hard that it would require much more labor in sanding to a fair finish. The cost of materials and labor would be daunting. I don't know yet what it is like to work on Interlock....
Thanks for advice on bottom paint. I had chosen a hard Interlux finish good for multiple years, but will look into Coppercoat now since the project is moving slowly to that step.
Thanks again for all the replies!
In answer to the question of why not just use epoxy without gel coat, my guys say there are two factors. First epoxy--especially good epoxy like West System--is quite expensive compared to gel coat. Second, and more importantly IMO, epoxy is so hard that it would require much more labor in sanding to a fair finish. The cost of materials and labor would be daunting. I don't know yet what it is like to work on Interlock....
Thanks for advice on bottom paint. I had chosen a hard Interlux finish good for multiple years, but will look into Coppercoat now since the project is moving slowly to that step.
Thanks again for all the replies!
The factors you mention about epoxy (expense and hardness) seem to be correct. Now that you mention them, I recall them from my research on the topic. I suspect that this is why many manufactures have turned to vinyl ester resins as opposed to epoxy or polyester. Less chance of blisters and less expense.
Hi all, I have a '93 Hunter 19 and need to do some keel (centerboard) repairs and was wondering if stripping the hull & bottom and repainting is something a DIY'er with some ability could tackle or if I should just redo the barrier coat. There are no clearly visible defects in the hull, and just a couple of small spider cracks on the deck near one of the stanchions.I'm interested in whether you have ever seen the gel coat below the water line on your boat, and whether you have done repairs on the gel coat. Here's the background (I started this in another thread in the medium sized boat forum, but this seems like a place more will see).
My C-27 was built in 1980 (1981 model). She's new to me, and she needed some cosmetic attention to spider cracks in the cockpit. Through a series of steps, the marine service I engaged ended up hauling her and moving her to their excellent shop. Having her out of the water with mast down, indoors, offers a number of good opportunities, one of which was to strip the bottom paint for refinish. We started that task with a grinder, and exposed the gel coat. Before the gel coat was revealed there were a few blisters to see--but not really much to see. Afterward the gel coat was bare, a large number of air voids under the gel coat and therefore incipient blisters were there to see. We ground all of these out for filling. Here's what she looked like:
Here's the surface appearance of the gel coat that reveals an air void below (both the thin crack and the bump in the surface):
Just for the record, all the repair has been done, and she has new gel coat, waiting for barrier coat and bottom paint, and she not only looks gorgeous, she's ready for another 50 years (I wish I were...). Here she is today:
I'm wondering how often owners do or have this done to their boats. Have you ever seen anything like what we found under the bottom paint of my boat?
Thanks for looking in!
First 2 photos are of the keel damage, last is one of the boat (sorry, no real detail on it).
Any comments or suggestions on how to tackle either of these tasks would be greatly appreciated.
Happy Sailing!
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looking at the bottom
I bought a 1977 Lancer 25 a few years ago. it was in a yard on the hard, evidently for a while .It was April in Rockland Me. when we first looked at her. and the cabin had Ice up to the seat cushions. we got a good discount on her too.
later in the spring we stripped the bottom paint as it was severely flaking off. the Gel coat wasn't too bad but the keel bottom had numerous deep gouges in it and the rudder was splitting we did find a few minor spider cracks wher the deck and bulkheads joined those we repaired. all in all she was a good boat.
I bought a 1977 Lancer 25 a few years ago. it was in a yard on the hard, evidently for a while .It was April in Rockland Me. when we first looked at her. and the cabin had Ice up to the seat cushions. we got a good discount on her too.
later in the spring we stripped the bottom paint as it was severely flaking off. the Gel coat wasn't too bad but the keel bottom had numerous deep gouges in it and the rudder was splitting we did find a few minor spider cracks wher the deck and bulkheads joined those we repaired. all in all she was a good boat.
I'm looking at a Catalina at a good price I think. Will a survey tell me that the bottom has these types of problems described above or do you have to strip the paint off to be sure that you are not buying a costly mistake. If the bottom has been painted recently it may look pretty but how do you tell it wasn't just painted over problems. I thought a diver could just check out the bottom and tell me about the Catalina Smile and condition of the bottom since he sees them all day. But now I don't think so. I know old sailboats are cheap compared to a new one but I could see having to spend another $10k by the time the boatyard fixes the bottom the correct way and puts the barrier paints and anti fouling paints on. This is an eye opener . Thanks for sharing. A $6k Catalina for sail with fresh bottom paint maybe a $20k Catalina when you run into bottom, engine and rigging replacement problems , or am I just overly paranoid .
Oh my GOD!!! 10,000 large for a bottom? Man, if we had more jobs like that, we would have newer trucks. You folks paying THAT kind of money need to come to OUR dirt pile. And no, I'm not soliciting at all, to my recollection I've never even said where the yard is. We've got an older Hunter 30 here that's dry, bad motor, and I'd say 2500 bucks would take it no problem. Sure, if a guy pays these blokes riding around in a forty thousand dollar truck, and a million dollar facility WILL take all your money for a fresh motor and bottom. (This is really a pretty simple clue that holds true for yards, car dealers, whoever, because somebody is PAYING for all that glitter, guess who..)On the other hand, pulling that little Universal and going through it, and a bottom job bearing in mind that very few of us are restoring the U.S.S. Constitution, it's a boat bottom on an older 30 foot boat. If memory serves me, the last 28'er I did had the bottom in BAD shape. Poor dude bought it out of fresh water, let a bunch of drug addicts out on the island that calls themselves a yard step it and launch it with nothing on the bottom but a slap of antifouling. A year later you get to guess how it looked. Very, very bad. Haul block and launch, cleaned, blasted, barrier coated, bottom painted I think was 2800.00 bucks. And if someone was willing to pay me ten large for a bottom, I would do the exact same thing, and put the other seven in the bank I guess, because throwing all that good money at a job is not going to make it one iota better, just more expensive. I could, by myself recommission this ol' Hunter, fresh the motor, clean it up, throw a bottom at it, and kick it in the creek for less that ten large. Next to a new boat? Holy Lord. Now I'm not trying to talk anyone out of buying a new boat, I'm more than sure they need the business.
It is not however cost effective. (I wish I could make that period bigger).
It is not however cost effective. (I wish I could make that period bigger).
The $10k is just a number I made up when I look at the Catalina 27 above. I live in San Diego and prices are maybe higher here. The boat yard will do all the work. They want about $1200. to pull a 27' sailboat out and paint the anti fouling paint over the blisters and put it back in the water. Any work other than that will raise the price. bobbyfinger 2001 what was the total costs of a job after the barrier paint and bottom paint was done and boat put back in the water? If you don't mind me asking.
Sorry it was PSR who posted the Pictures. The reason for me wanting to know about this is because I'm going boat shopping today. Thanks
The cost to peel a 35 foot sailboat to the fiberglass, sand away any deactivated resin, seal with several coats of new resin (possibly adding fiberglass), fairing, bottom paint would be about $12,000.00 to $15,000.00 if done by a yard. The same job would cost between $1500.00 and $2,000.00 to DIY. The cost is in the labor. Doing the job once would convince you of why it is so expensive.
Too true, rajhnsn. I stripped mine down to the gelcoat this summer by heat gun, scraper and then sanding with orbital sander. Stripped keel with a needle scaler. coated keel with rust converter, faired, filled any osmosis pits (few) and then 4 coats of Interprotect 2000. I figured my cost to be about 2000- one k of which went to a contractor to do the needle scaling and heat gun and scraper. a once in a lifetime job.
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Thank you for the answers on costs. I'm looking at these old boats in a much different light now. I want the hull ( foundation) to be in good shape before I do any other mods. Just one more question. Is the only way to tell that the boat needs extensive work done to the hull is to strip or sand blast it down to the Fiberglas?
You should be able to tell by stripping down to the gelcoat. If there are only a few blisters they may be able to be filled individually. If there are many (hundreds), it would probably be better to have it peeled. The size and type of blister is important to know as well. Small gelcoat blisters are less of a problem than large blisters that have formed in the fiberglass. Some blisters will recede into the gelcoat when they are dry and they are not able to be seen if a boat has been out of the water for a few days. Boats that have larger blisters that are wet inside after a boat has dried are usually in the fiberglass and may indicate a bigger problem. Some gelcoat blisters never amount to anything more than what they are, some continue to spread into the unreacted resin in the fiberglass. I knew there were blisters when I bought my boat but worked some of the cost of repair into the deal. It was more extensive than I expected but at some point you have to take a chance. There is no way of knowing for sure unless you have the paint blasted off at the time of the survey. This would very likely be at the buyers cost.
Thanks rajhnsn. This has been very helpful. I can see why now some seller want a lot more for their boats than others when the work has already been done.
"Doing the job once would convince you of why it is so expensive."
I couldn't agree more. I spent over $1200 in materials alone on a 19" O'Day Mariner.
Been there, done that. I had years of bottom paint soda-blasted off and found a gazillion small blisters, [think 1/2 a BB] some larger but not too many. Boat was a 1970, and it didn't look like the bottom paint had ever been removed.
I ground out every blister with a burr on a die grinder, quite a job in itself but a walk in the park compared to sanding the fairing compound..
I followed West System's guide. After all grinding was finished, a coat of epoxy, pushed into holes with a spreader, and before that kicked off, a coat of 407 Low-Density Filler.
After that was all sanded fair [over head with an air powered board file- quite a workout!!],
6 coats of epoxy with their barrier additive. Sanded that with a DA sander then bottom paint.
On a 19" boat I used about 6-7 gallons of W.S. This was NOT a weekend project.
Quite a job, but, I think it's good for the next 40 years.
robj
I couldn't agree more. I spent over $1200 in materials alone on a 19" O'Day Mariner.
Been there, done that. I had years of bottom paint soda-blasted off and found a gazillion small blisters, [think 1/2 a BB] some larger but not too many. Boat was a 1970, and it didn't look like the bottom paint had ever been removed.
I ground out every blister with a burr on a die grinder, quite a job in itself but a walk in the park compared to sanding the fairing compound..
I followed West System's guide. After all grinding was finished, a coat of epoxy, pushed into holes with a spreader, and before that kicked off, a coat of 407 Low-Density Filler.
After that was all sanded fair [over head with an air powered board file- quite a workout!!],
6 coats of epoxy with their barrier additive. Sanded that with a DA sander then bottom paint.
On a 19" boat I used about 6-7 gallons of W.S. This was NOT a weekend project.
Quite a job, but, I think it's good for the next 40 years.
robj
