CS17 Hull 129 Paint

[Tom Williams]

Looking for some advise. I getting close to gluing the seat sides on my CS17 and decided to paint inside of the hull while I had easy access (yep ... I'm paying attention to advise in the forum). I bought some Interlux single part polyurethane paint (Brightsides) for at least the locker interiors. I painted over sanded epoxy last Saturday evening. It Wednesday evening now and the paint is still slightly tacky. I'm building in my basement, and with the cold weather we've been having, the temps about 60 - 65 F down there. The label said it was acceptable to paint down to 50F and it should be dry within 16 hours. I put a small fan in the boat tonight to help circulate some air. I probably just need to be patient but would like to hear someone tell me everything will be ok.

Attached is a shot. Note the forward locker (the one my helper is sitting in). This will be a wet locker for the anchor, bucket, lines, etc. The locker aft bulkhead will provide support for the centerboard trunk forward end.

Tom

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[Guest]

Well, there is better paint for lockers than Brightsides, that is an epoxy based two part paint, that works for the long haul. It has also been my experience with birghtsides, without a primer it mildews terribly and does not even hold up unless you put around six coats of that stuff on a surface. I am sorry to say, you have not done yourself any justice with it. Find yourself a bunch of cotton rags and remove it with mineral spirits, repeating the wiping and finding a new place on a wet rag.

. The stuff will give you nothing but grief in this application. This is only my take from previous experiences with it. Lockers can be painted with Glidden epoxy mix, colored to any color that you wish, but comes in white tintable base and works well. Sherrin Williams makes a TIle Clad two part paint, and Benjamin Moore does also, called Polymide Coatings. Be careful with the fumes indoors.

[Frank Hagan]

You can get a reaction between epoxy and oil based paints, so its wise to try a small area and do a scratch test first. In this case, the point is moot ... if it never cures then it is probably an incompatibility. I don't fully understand all the chemistry involved, but it doesn't really have anything to do with the amine blush you hear so much about. So all the prep in the world wouldn't have made it cure. And because paint formulations change, what you used 2 years ago may not be the same formulation today, so you have to test it again.

A lot of people are using high quality water based latex paints inside boats now, although it is softer than I like for inside of lockers. You avoid the chance of a reaction between the paint and the epoxy, but you can still have adhesion problems if you don't wash any amine blush off the epoxy first. But, latex is easy to apply, easy to touch up, and cheap to boot. But, you will touch it up a lot if the lockers get a lot of action.

Practical Sailor is testing paints, and several readers have said they use Rustoleum for boat interiors ... they are testing Rustoleum right now, and its holding up well (although its been only one season). Its a "hard shell" oil based paint, which can take a lot of abuse, but you would need to do a scratch test for adhesion with your epoxy.

Scratch Test: prepare and paint a small area. Let cure. When fully cured according to the label directions, take a metal straight edge and razor blade and make a series of light cuts in the paint, about 1/8" apart. Make another series of cuts at right angles, so you have a cross-hatch pattern of cuts in the paint. Take a piece of cellophane tape and place it on the cross-hatch, burnishing down one end of it well. Then, rip off the tape. If the paint came off in little checks onto the tape, you have an adhesion problem, and the paint won't last. (This tip is from the Systems Three Resins' book on epoxy).

[Scott Dufour]

I ran into a similar problem with a small boat I painted last year. It was an oil primer on epoxy, well prepped. For some reason, those oils can take forever to dry over epoxy. I just got really, really patient, and let it sit for about six weeks. It eventually hardened up.

I used a water based primer (Kilz II, I think) on some my CS17 lockers, and it dried in about a day, and stuck really well. I haven't painted over them yet, but I'll probably use a Benjamine Moore "Impervo" oil based paint. It's a lot like the Rustoleum, I think.

[Guest]

The oil base Kilz is a fine primer on bare epoxy resin and glass, creating a very strong bond, if you intend to use an oil base paint, if you prep it right. Apply it in thin coats, as it has a tendancy to become thick at the half and bottom of the can. Thin it with some mineral spirits. It dries in no time. Fumes are a little a strong in a closed enviroment. Roll it, as it will lap with its drying time being pretty quick in new cans. This also hides any pin holes and the likes that you may get in resin and some fairing compounds.

[Howard]

Don't consider me an expert at all....but as per the System 3 Epoxy book:

"alkyd enamels (and Brightside Polyurethane is an alkyd....look on the ingredient list) may not properly dry on epoxy. The reason is that epoxy resins, despite sanding and long time curing, remain chemically active to certain components of alkyd paint and varnish systems. The free unreacted amine in the epoxy resin coating interferes with the action of the metallic driers in some of these paints. If this happens, the paint surface may dry, but remain soft and tacky next to the epoxy resin surface."

No mention is made of the primers for these paints, and if they buffer this chemical reaction. I've used Brightside on epoxy, but primed it first, and I don't feel I had any problem. I did paint a epoxy/glass covered foam wing once, and felt the paint reacted with the foam to soften it....which I now feel was due to the oil base and solvents working on the foam. Polyester resin will eat foam, epoxy does not.

The S3 Epoxy book goes on to say that the reason polyester based gel coats do not work on epoxy is that the amines also inhibit the peroxide catalyst, preventing cure at the interface.

In comparison, it says that 2 part LPU paints may actually bond with epoxy.

And lastly, it says that you should avoid dark colors. This last bit is hard to understand as S3 also offers a waterbased LPU paint, but mostly in dark colors!

The waterbased LPU paint is appealing to me. The results are said to mimic the gloss and durability of 2 part LPU paints, but can be sprayed on without special breathing equipment and multiple coats can be applied without sanding. I've got their sample kit, but haven't tried it yet.

The S3 book can be viewed or downloaded from the S3 website, by registering with them (free):

http://www.systemthree.com/m_register.asp

I ordered sample kits from both Raka and S3, and after working with them both, I ordered from Raka. It was just as easy to mix, and I got a better finish with nominal bubbles. And it's cheaper.

Howard

PS: The results of my primary/secondary bonding test? In both cases, the wood broke before the joint did. (Raka)

[Tom Williams]

Hey thanks for all the good inputs. I checked the paint this AM and it appears to be hardening. I think the fan is helping. I'll try the peel test Frank recommeds. If it peels, I'll strip it off and go with the oil based enamals most of you are recommending (I like the $ advantage as well ... $30/ quart is tough to swallow). If it appears to be sticking, I'll have to think on it some more.

I had no idea the most complicated part of building a boat is selecting paint! Everything else has been simple in comparison. I did look into epoxy paint (Sherwin Williams). The guy at the paint store told me he wouldn't recommend it for a boat, saying it would peel. I thought I was playing it safe going with a special paint made for boats. The guy at the marina where I bought the stuff said he had used Brightsides over epoxy lots of times and said it didn't require the primer (but he'd gladly sell it to me if I wanted it). He recommended just a good sanding.

I'll keep you informed!

Thanks again, Tom

[Tom Williams]

Thanks for the advise. I took Oysters advise and striped the #@#%**& stuff out of there. It must have been an epoxy incompatibaility issue as Ray suggests. The paint dissolved right off with paint thinner where I had sanded throughly. The areas that I sanding access problems with (corners etc.) seemed to cure well. For reference, I'm using Systems 3 epoxy.

I think Frank has the best idea, experiment before commiting to a big area. I'm going to try the Rustoleum idea. My boat will be primarily on a trailor with no more than a week or two in the water at a time. I've used Rustoleum on other outdoor projects with good success and I can get it easily at Home Depot. I'll let everyone know how it goes.

Thanks for the help! Tom

[Tom Williams]

I went with the Rustoleum for at least the lockers. I followed Franks suggestion for the bonding test ... no problems. I got two coats on the locker insides and on my locker drains. The paint was a pleasure to work with and has dried "hard as nails". Any reason not to use this stuff in the UV exposed cockpit? How about on hull bottom? Are the polyurethane paints really that much better?

I got the seat sides glued on this AM. Another couple of weeks and I'll be ready for the "flip". Can't wait for the maiden voyage!

Tom

[JeffM]

A useful thread.

For the reasons Ray mentioned, I'm not going to paint anything not exposed -- I like the idea of being able to check the condition of the wood under the hatches, and I don't think the ship's rats will object to the decor.

[Frank Hagan]

I went with the Rustoleum for at least the lockers. I followed Franks suggestion for the bonding test ... no problems. I got two coats on the locker insides and on my locker drains. The paint was a pleasure to work with and has dried "hard as nails". Any reason not to use this stuff in the UV exposed cockpit? How about on hull bottom? Are the polyurethane paints really that much better?

The two part, professionally applied polyurethane paints are better, and some of them can be applied with a roller and then "tipping off" with a dry brush. The spray jobs look like an automotive finish, very glossy and very hard. I've heard the results with rolling and tipping are nearly as good as the professional spray jobs once you get it down pat. The only direct experience I have with the two part polyurethanes being applied by hand was a rather interesting disaster my neighbor had ("disaster" is probably too strong a word, but suffice it to say it didn't look very professional!) But maybe someone here has done it and can fill us in.

The "one-part" polyurethanes are no better than Rustoleum, in my opinion. I've not been too happy with Brightsides or Petit, although I have to admit my can of Petit Easypoxy was on a clearance sale and perhaps there was something wrong with it.

[Scott Dunsworth]

Tom I am using rustoleum on the whole interior of my boat. I stoped by my local hardware store ( Ace, Truevalue ) and found out that rustoleum makes actual marine paints. They where able to order me rustoleum marine primer ( $18 quart). I can tell you that it drys very good on raka epoxy. Then I painted with regular satin white rustoleum. I did take Oysters advice and added mold and mildew preventer to the paint.

On the topsides I will order rustoleum marine paint ( $12quart). The paint is sticking and harding very good. I had a piece that I cut off of a painted plank and put it on the workbench I had to bare down with a sharp tool to damage it.

The book we looked at only showed about eight or ten colors in the marine line.

Scott

[Tom Williams]

Thanks Scott. I checked the Rustoleum website and saw the marine paint advertized as well. I'm thinking us midwest guys can probably get away without the premium stuff the coasters need to use. I think I'll order the primer & marine grade enamal for the cockpit and the hull. I'll keep you posted as I learn!

Tom

[Pat Mellema]

I was in Lowes today to get some varnish today and they had the full line of Rustoleum marine paints. You might want to check before you go somewhere and have to order it.