Painting Over Epoxy

Hello, I Am New To This Site And Had Some Questions. If Anyone Can Help, Would Be Greatly Appreciated.

I Have Just Had To Do Some Major Hull Repair With My Yamaha Ls 2000 Boat And Had To Add A Lot Of Epoxy To Smooth Out Hull. In Regards To Paint, Is There Anything I Can Do To Just Paint The Patches And Have The Rest Of Paint Remain The Same? I Keep Hearing About Gel Coat, Is This Necessary? Is There A Recommendation For Correct Paint To Use, Damage On Bottom Slightly, More On The Sides.

Any Advice Appreciated.
Improp

 

Good question. You can't gel coat over epoxy, thats one of the nice things about polyester.

I'm kind of interested in hearing what variety of coatings folks apply over epoxy, now myself!

Mike

 

I have used epoxy in all my boat building projects and when requiring a colour finish always use two pot polyurethane marine quality paints. As long as the epoxy is sanded first to provide a good key (I use about 240# wet & dry) the results have always been excellent. I always use a brush or roller, the paint being solvent based is a bit toxic, and I don't like the idea of spraying.
Interesting, that on one boat I wanted a tougher finish than the 2 pot, so decided to lightly wet and dry the final coat of polyurethane, then brush on a thin coat of epoxy resin. Worked a treat, and was even was more glossy than normal.

 

Frosh,
Considering that epoxy is not UV stable, wouldn't that top layer of epoxy have rather quickly died?
Did you have that boat long enought to find out.
When varnishing wood, one way to do it is to undercoat with epoxy resin, and then topcoat with varnish. This works because the varnish is UV stable, and will shield the epoxy...

 

Hansp, you are quite right regarding UV degrading exposed epoxy, however I was not recommending the final coat of epoxy over the paint to any one, just making a point of what can be done.
For your interest this is on my home built sailboard that has a 1.5mm marine ply bottom that has a partial blue pattern and the remainder clear woodgrain. The exposed epoxy has a UV retardant formulated in the hardener, (probably would only slow the process) and is only on the bottom of the board. The board spends 99% of its time in a bag. The finish still looks perfect 3 years later.

 

Sorry IMPROP- butt in if you want-
Frosh, Interesting, and now I understand.
Is this done, or recomended, very much?
Also, could this be done over laquer?
just curious- probably wouldn't anyway- But..
For instance, I could concieve of epoxying over the extensive laquered woodwork inside my cabin (30ft Van De Stadt Seahorse).
Theoretically this might give me more life for my upcoming laquer job, and a harder surface. Very small windows- UV damage probably wouldn't be much of a problem, especially with UV retardent.
Possibly just more work when it finally does need it- or maybe the heat gun and the different layers might just strip off a dream...
Probably a stupid Idea but- What do you think?

 

Hansp, I don't think the final coat of epoxy is ever recommended. I thought that a continuous hard coating would be great where colour and woodgrain are both present on one surface, particularly when abrasion by sand is going to occur. Therefore I wouldn't bother for in your boat cabin. But give a lot of thought to which lacquer you will use. Polyurethanes are tough and very water resistant. You can get water based, solvent based one part, and solvent based two pot. All are excellent in a marine environment, and the biggest enemy of all types is..... you guessed it prolonged UV exposure.

 

Again, IMPROP, sorry,
Thanks Frosh,
The stuff I have gone for,
but have not yet opened so theoretically am not locked into,
is the 'International Goldspar Original', one pot solvent based.
Any opinions on this?
I plan to do a small amount of woodwork on top, first penetrating wood presevering epoxy, then normal west system epoxy, then sikkens two pack polyrond (to fill the valleys and lay a good final base), then finally the Goldspar... Sounds like a lot, but I have it on pretty good advice.
Inside, I am not too sure what to do. I am trying to get my boat finished quick, to get it back in the water. I don't know if I should actually strip back the inside- with the help of heat gun, to do something similar as on top, or just leave it all till we are on the swing mooring and do a simple sand and laquer. (I am thinking while we have the power, strip it now, and epoxy and laquer it later?)
No stress really about the inside, we can after all leave a few things to next year, as at the moment we have just gone over the three weeks dryed out mark, where the yard rates have just doubled. In another three weeks, yep, double again. Can't afford that next double, so speed is important.
Hans.

 

Goldspar is polyurethane designed for marine use and good to my knowledge. One part is good for inside the cabin. For external work on a boat I would go for the Goldspar Perfection, which is 2 pot, therefore will be harder than the one you have now. However if underneath you have West Epoxy, it wont matter that much whichever version of Goldspar varnish you use as the wood will not be penetrated by minor abrasions. Good Luck

 

If you were to use epoxy on the interior surfaces, personally, I'd strip the current finish and apply the epoxy to the wood itself, then apply a varnish finish coat. The problem is, it's work, work, work, .... I built a 16' wood, epoxy, glass sailboat that is completely "bright." Major, major time investment in the finish.

Personally, since you have an existing interior, there will be little benefit to using epoxy since you will not be encapsulating the entire interior joinery. The exception would be in high wear areas where durability would be an issue. In those areas, I'd still use epoxy as a substrate. I feel that varnish is more durable over such a substrate.

In your circumstance, since time is an issue, I'd sand and varnish and go on to more important things. Being a protected environment, that might be all that it needs.

The product that I've found that gives the best (so far) finish is Z-Spar. It's also the most expensive varnish I've used. I varnished my boat with it using a 3" foam brush and I could almost swear it was a spray finish. No brush marks what so ever!

Good luck on your project.

 

I use any epoxy high build primer and then good ole PPG car paint to finish. seems to work well for me.

 

Car Paint?
Really?

What is PPG?

I happen to have a big tin of car paint enamel, a rather nice color, that I got mixed up for my 74' Transit van. I wonder if this would be any good?

The guy before me has been using Dulux Weather Shield on my boat, Oil on the topsides and acrylic on the deck and cabin. I was simply going to continue this tradition as while the deck and cabin is stripped back to wood, the topsides are not (also, here they seem to be recomending this paint for comercial fishing boats).

Hans.

 

Great thread.

I hope to get around to redoing my teak this summer. Had lots of bad luck with finishes that don't work. I like the epoxy / 2-pot idea, and the West system manual agrees that that is the most durable finish with the best UV protection.

Manual also says you can gel coat over epoxy, so I just wanted to correct myself above. I have read in multiple cases that this is not recommended, but I guess you can. Still in the shallow end of the learning curve.

Regards,

Mike

 

Yes Pittsburg Paint and Glass (PPG). Been using it for years, Gives a good finish holds up well against the sun even holds non-skid. I do not use clear coat but have worked around a boat painter who says it holds up better than any varnish he has ever used. But he said that no epoxy needed. me , I'm a firm believer in epoxy as long as you coat every piece inside and out and all the edges.

 

Bilgeboy

You were correct the first time, don't use gel coat over epoxy. In the West System information it says it's ok to do, so I called WS and discussed it with them and they agreed that while it may work (sometimes), it's not the best or easiest product to use over epoxy. None of the chemists in our lab, nor any from other gel coat companies that I know of will recommend applying gel coat over epoxy. I'm not saying it's impossible and can't work, but in my experiance and in our lab testing, it's difficult to get a good bond.