Epoxy barrier coats?

O

onefam

New member
We bought a 5-year-old C-Dory that has never had bottom paint. We intend to keep the boat in the water. Posters here advocate a chemical wash to rid hull of any waxy coating left from the molds, multiple barrier coats of epoxy paint, and a couple coats of bottom paint. (Most of these boats are in warm places -- FL, TX, So. Cal.)

Talking to local boat yards around northwest WA, I get different and conflicting advice. All say no wax is likely to be on the hull after 5 years of use. Most say the epoxy barrier coats are not necessary and almost no one up here does it; only one said he’d put 2 coats of epoxy on if he were doing the job. SeaSport (C-Dory) says they have no idea, no opinion. Any advice appreciated.

First time posting so I hope I haven't screwed anything up.
 
I just went through this decision process a few weeks ago. We recently purchased a 2006 Cape Cruiser that never had bottompaint. Since much of our boating at this point will be in warmer water, and hopefully for periods exceeding a month I thought bottompaint was necessary this time.

The question was whether to spend the extra money (several hundred dollars) for barrier epoxy beneath the bottompaint.

I asked various folks (and a few C-Brat's) their opinion, and got responses on both sides of the question. Some mentioned that since most newer boats were made with vinylester resin that reduces the blistering possibility. Some others thought a barrier coat might be a good idea if the boat was left in the water for long periods. All seemed to agree there was no down-side to a barrier coat other than the cost/work involved.

Since the issue was something that needed to be decided before the bottompaint was applied, I opted to do the barrier coat as well. Doing a barrier coat later would be impractical.

Another minor issue I considered was that the CC23 has no warranty coverage due to the whole Cape Cruiser/C-Dory flap. That was another small factor in rationalizing my expensive decision.

Good luck with your decision!

Best,
Casey
 
We applied a barrier coat to our CD22 last year. We used Interlux's Fiberglass Prep Wash 202 to remove the wax - not that expensive and very easy to apply. Basically, you put on the hull with one rag and remove with another rag (change out rags frequently). We also purchased some dewaxer from a local auto body shop that was much cheaper.

We then applied 4 coats of very thick (it was around 40 degrees during applying) of Interlux InterProtect 3000 Epoxy Primer. We used the 3000 version in order to be able to apply the barrier coat in colder temps. Also, we like the "white" version of the bottom coat.

Best part of the barrier coat - we spent many nights in the North Channel sitting on rocks and the barrier coat protected the bottom.

We did all the work ourselves and had no problems with the epoxy holding or any other issue.
 
Hi Folks,

This is a good topic.

I have a 1983 Angler Classic. A few years ago, I added a 75 HP Yamaha Four Stroke engine, and had to raise the water line 3" at the stern. At Just above the water line the gel coat is getting a bit rough. I thought of putting a clear epoxy coat on the bottom and up to the first chine. I am thinking that it would stop any water reaching the core.

I would first strip off all the bottom paint.

I would then add a few coats of the new bottom paint.

Any ideas.

Fred
 
1. There is no information on this site (that I am aware of) indicating whether a 5 year-old C-Dory was laid with polyester or vinylester resin. Even with newer boats, it is my impression that the smaller models do not have any vinylester. Vinylester is more blister resistant than polyester.

2. Even with the Tomcat (which has a vinylester layer on the outside), Jeff Mesmer, who was at C-Dory when I bought my Tomcat, recommended putting on epoxy if the boat was going to be kept in the water full-time. I respect Jeff's opinion. For a polyester hull, there is no question that an epoxy barrier coat should be put on before the bottom paint is applied.

3. There is a ton of discussion on this site on the issue- search for
bottom paint/epoxy/vinyester/blisters.
 
Agree, that if you go to the trouble of putting on bottom paint, you need to put on barrier coat. In S. Calif--all be it slightly warmer than the PNW--as many boats as in Florida got blistering.

Once bottom paint is on, it is very difficult to get it off to get a good epoxy bond. You will have to do alot of sanding or a peel--not recommended on any C Dory.

I just pruchased a "new" boat, and it now has 5 coats of epoxy barrier coat. Good insurance.
 
With the various brands of boats we have handled new, we have never applied a barrier coat before bottom painting a hull on a new boat, and have had no blistering problems.

There are many on this site who are passionate about the need for barrier coating and would probably never have us do the work because we don't recomend it.

If someone wants it, we will gladly apply it, and charge accordingly. But the reality is, in the Pacific NW, in over 20 years of doing this, we have never seen the need for barrier coating.

Other climates, or fresh water areas may be different.

Keep in mind- It is not practical to barrier coat after the fact, so if there is any doubt in your mind, do it. But when the majority of the yards you talk to don't recomend it, even though they could make more money off the job, I think that may be the most telling advice.

If it were my boat, in these waters- I'd save my money and go with no barrier coat.

BTW- we wipe down with acetone, before and after sanding the hull to remove wax build up. The sanding is to rough up the gel coat to get good adhesion of the paint.

Interlux makes a primer that requires no sanding, just wax removal, although we've found it just as easy and cost efficient to sand the hull.
 
Good to get a local perspective from a PNW guy, Matt. We had no problem with the bottom when we have cruised up there, for a couple months at a time. Of course, that may be because the water is so freakin' cold! :xseek

Keep in mind that the Brats are a traveling, cruising bunch... and may haul their boat south to the warmth. Or to fresh water. We put epoxy barrier coats on Wild Blue. As Dr. Bob stated: "good insurance." All the yards in our part of the world recommend it. It isn't that much more work once you've got the boat in the air to do the bottom.

For the original question - it won't cost that much more and it is more protection for the hull. I'd recommend the epoxy barrier coats. Once you start running that boat, you may not want to go home. :wink:

Best wishes,
Jim B.
 
My 2005 CD came from Fla. and has bottom paint on it. It looks like it has had at least 4 or 5 coats as you can see the places where it had come off in large areas and repainted and repainted etc. The boat was kept in the water there.
Now I have it in Alaska and it stays on the trailer when not out fishing but it goes on/off the trailer 3 or 4 times a week. This has really raised hell with the bottom paint in that it is scraping off on the bunks. So far I just touch it up to keep it looking ok. When the paint comes off it is all the way to the white fiberglass which leads me to believe it was not applied properly.
Can the bottom paint be removed completely, easily without damaging the fiberglass surface ?? I do not need it on the boat.
Obviously this is not an eminent problem as I am not going to lay in the snow doing bottom paint.
Thanks for any ideas.
 
Thanks for the thoughtful info and advice. It sounds to me like the barrier coats are not necessary in NW WA waters IF the hull is vinylester rather than polyester (though it's relatively cheap insurance). The question for me now is: were 2004 CD25's built with vinylester? Does anyone know? Or know how I might determine?
 
FWIW-

A 1986 Bayliner Trophy 25, with polyester resin, that has been in the water since day 1 and never had a barrier coat was recently sold by us, and upon haul out had one blister about the size of a quarter.

The 1985 Carver 32 I owned had a handful of blisters on it at haulout in 2005, three of which where bigger than 2 inches in diameter. These were ground out, wiped with acetone, filled with "Kitty Hair", faired and painted with modified epoxy bottom paint. At next haul out there was no sign of blistering in these areas.

My opinion (and worth what you paid for it) is that blisters in the NW are a rare occurance on boats, with the exception of Uniflites and a few other lines where blisters are a known issue due to a resin issue. For the vast majority of boats, it isn't worth the energy expended worrying about it. If a few blisters occur, fix them and move on.

The other issue with a use dboat that has never been painted, is that the barrier coat may very well trap water in the gelcoat, and create blister problems when none would have existed.

As noted, if a customer wants barrier coat, we'll do it. It isn't what we recomend and isn't our usual procedure.
 
It's not common up here in NE either (at least in salt water) unless a boat will sit in the water full time. I had to raise my paint line and opted to add epoxy barrier coat just to that area. The rest of the hull was already painted and I left it as is.

If I had a bare and new hull, I would personally add the barrier coat for the insurance. Otherwise, I would just keep an eye out and not worry about it.
 
Matt Gurnsey":2ev0qk12 said:
My opinion (and worth what you paid for it) is that blisters in the NW are a rare occurance on boats, with the exception of Uniflites and a few other lines where blisters are a known issue due to a resin issue. For the vast majority of boats, it isn't worth the energy expended worrying about it. If a few blisters occur, fix them and move on.
Click to expand...

Wish I had known that before I had my boat done, right after I purchased it. Master Marine recommended that I have it done at LaConner Maritime, and based on discussions here (which now I think were Florida-specific) I had a barrier coat applied before the bottom paint. The good news is that the boat is protected for southern cruising.

Warren
 
Personally, I think you did the right thing warren. If you are going to leave it in the water for extended periods. My blister experience is mainly from sailboats in the water year around but some c-dorys do the same. And east coast or west coast, they can blister. Just go to any large boatyard in the northwest and you will see a lot of boats with blisters. I had them on some boats and none on others. The vinylester gelcoat on my last boat never got blisters in the ten years I had it so that may be a pretty good barrier.
 
I do leave the Tom Cat in the water for 3 seasons, once for 4, so I'll think of it as extra insurance. AFAIK, barrier coat is permanent, and only the bottom paint will need to be maintained.

Warren
 
I have been following the blistering problem since the late 60's, mostly because of my scientific background. When we were cruising Europe in the mid 80's we visited many boat yards to evaluate how much blistering was occuring there. The only two boats I have seen rendered unusuable by osmosis were in the Med. (other than Uniflites and Valiants during a certain peroid) They had been laminated in the colder climates and were brands which had excellent reputations. They were then brought to the Med, and in a few years, actually had severe enough osmosis that there were holes in the hull. I have seen a number of boats which had zero blistering for the first 20 or so years, but then later in life developed severe blistering in the same waters. I have seen boats which were sand blasted, with no blisters, be hauled the next year, and have multiple blisters. We purchased a Cal 46 which had a blister repair and epoxy coating of the bottom, 4 years before we purchased it. There was no blistering when we took delivary of the boat in S. Calif. The next year it was sailed to the PNW and in 3 years had recurrance of the blistering, while only in the PNW waters.

There is another phenomen which is not discussed as often, but is somewhat related to the osmotic issues. That is a "floppy hull". Basically there is moisture migration along glass fibers, and breakdown of the stiffness of the hull. Part is do to resin decay, some is due to the boat working, and there may be other factors, such as freeze/thaw cycles. Some boats have been destroyed because of this. (Not trailered boats to my knowledge)

To answer Jacks' question about removal of bottom paint. Yes, you can remove it. There are chemical strippers. You can strip it off with sanding and scraping. You can have the boat lightly soda blasted (should be by someone who is very experienced, so that the gel coat is not damaged).
After that, you can put on epoxy primer, and then an epoxy based paint or some other enamals. You do not want to use two part Linlear Polyurethane under water, it will lift and blister under the paint layer.
It is almost impossible to get back to a good gel coat, and use that gel coat as the protective coating for the bottom. As Matt noted, you will scuff up the gel coat before painting, and this will allow small amounts of bottom paint to get in the small "cuts" made by the sand paper. Trying to re-gelcoat the bottom is expensive.

You might consider stripping off the current bottom paint, and putting on a hard bottom paint. It is also possible that ther various layers of paint were not compatable when they were applied. For example, a hard paint was applied over an ablative paint.
 
Just FYI, we wanted to report what we learned and decided to do on a hull that had never been bottom-painted, as we prepare to keep it in a slip.

We appreciate that many knowledgeable people here in the PNW do not see the need to spend for epoxy barrier coats, but we agreed with comments that it’s relatively cheap insurance, given that the boat would be hauled and sanded for bottom paint anyway.

Moreover, there isn’t unanimity of expert opinion on whether blistering is a problem in the PNW. Steve at B&J Fiberglass in Bellingham, where we rented space to do our painting and repairing, made two points. He said that he’s been doing boat repair in the area for 40 years and seen plenty of hull problems due to water migration. Second, while acknowledging that vinylester resins in newer hulls effectively resist blistering, he said these resins are frequently imported from countries like China where the exact composition of the material is not known for certain. He recommended barrier coats. Two gallons of Interlux 2000E gave us three coats.

There was also difference of opinion on the necessity of wiping the hull to remove any release wax that might be left after five years’ use. Again using the “cheap insurance” logic, we did it, using Interlux 202. After sanding, we wiped with acetone.

For bottom paint, we went with epaint EP-ZO, which is copper-free. We wanted to do our bit to reduce toxins, but also we notice a trend around the country toward banning copper bottom paint, and we’d prefer not to be changing paints when we recoat in the future. The epaint EP-ZO had a very impressive review in a multi-year study of 54 paints written up in Practical Sailor a couple years ago. We put on three coats, five on the water line, and hope to go two years between recoatings. We’ll see. Thanks for the help.
 
I have never heard of a "difference of opinion" about removing wax before coating with epoxy. That is something which must be done. If there is mold release wax left, the epxoy may not properly bond. Also the gel coat must be scuffed up, with sandpaper.
 
The question was, is there likely to be any wax to remove if the boat had been run for five years. As I wrote initially, I talked to a number of boatyards and “All say no wax is likely to be on the hull after five years of use,” making the solvent wipe-down prior to sanding unnecessary in their opinion. Posters here, however, recommended the step, as did Steve at B&J.
 
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