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After visiting the website of the friendly folks at www.fibreglast.com, I've decided to gelcoat my hull instead of painting it. The materials are about the same cost as paint, and I would say it's almost exactly the same amount of work. Never done it before, but there's a lot of info on the site, and when I called, the sales guy was VERY helpful, and took his time to converse with me about my potential project.
Essentially, the plan is to grind the gelcoat to clean, removing as much as I need to so as to arrive at either clean gelcoat or even the mat/cloth. Fill and fair with regular resin/MEP-K where the gelcoat is missing or repairs are needed, using microballoon filler, and mat/cloth/roving as necessary. You can also fill/fair with "Bondo" type filler, as long as it's polyester based, which most Bondo and I think Everlast products are. From earlier reading (mostly West Systems materials) I thought epoxy resin would have been better, but the guy at Fibreglast convinced me otherwise. (Heat generated/ same material equals primary bond, not secondary.) Whalers are normal resin boats, and I'll get actually a better bond with the regular. Then sand down the fairing to make it all shaped properly. Above the waterline on the outside of my hull is in good shape, so all that's needed there is to scuff it with 100 grit with a random orbit sander (and hand sand the corners and edges).
Wipe with acetone. Mix white gelcoat with high gloss additive (one to one) and add catalyst, and spray on hull with an HVLP sprayer, using at least a 2mm tip. (That's what I painted the deck with, and Fibreglast sells HVLP sprayers, and recommends them for gelcoating.) About six coats will take me to the recommended thickness of 20 mil. There is a cardboard guage you can buy to check the thickness. Last coat could include a special wax intended for below the waterline, but makes the surface "a little blotchy". I'm considering leaving it out. The coats go on one after the other -- more than 10 minutes apart, less than 25 minutes. One gun cup of my sprayer will do about half the hull, so I'll do one side at a time. The timing works out to spray a little acetone through the gun, mix up another batch, and spray some more.
Then spray PVA sealer over the whole thing. Gelcoat won't set up hard unless it cures covered. After it kicks hard, you wash the PVA off with hot water. Sand the surfaces wet with wet-dry sandpaper, finishing with 600. Buff with rubbing compound, then polishing compound. Wax. Flawless surface, highly abrasion resistant. Attach stickers. Go fishing. The sanding removes "orangepeel" or spray marks, and the compounds take care of the fine sanding scratches and bring it to full gloss.
White gelcoat kit is about $50/ gal and the gloss additive is about $100 / gallon. My 17' whaler should need a little over 2 gal, total. Maybe two and a half. Add sandpaper, resin and microballoon filler, etc, and you have maybe $300/ $350 in materials. Shipping for my whole caboodle is under $50, including a $20 charge for the high gloss additive, which is consider a special handling hazard by the shippers.
I'm still going to drill my bottom every winter for a while... at least I know how to repair the holes and gelcoat! And I'll save a little of the gelcoat just for that.
Will post as I go along on this thread. Would welcome advice of any kind.
Dan, I read your post here and at the other site and either you are being mis informed or maybe you don't understand either way it is very easy to lose your way when dealing w/ so many different products (been there).
1. You are not supposed to put polyester resin over epoxy but you can put epoxy over polyester.
2. You thin the last 1 or 2 coats of gelcoat not the first.
3. PVA is more difficult to use than wax as far as getting an even cure.
4. If you use epoxy resin you need to let it fully dry and some companies want you to use a tie-coat between the epoxy and the gelcoat.
I hope this helps, check into it a little more.
John Fyke
Re-Fit or Reef It
1979 15' Sport with Super Sport conversion and 70hp mercury.
I did know the first item... hence my question on the other site about what to do with those repairs. Your fourth point has given me something to look into.
As far as thinning goes, I was told that the duratec would thin the gelcoat properly one to one (the last coats, as you said) but won't I have to also thin the first coats with acetone enough to achieve a good spray pattern?
The PVA point is helpful. I'll look into the wax. Last thing I want is something else to be difficult! Is it "styrene" wax that you're referring to? If I add wax the last coat, I won't have to cover it with anything else for it to kick hard? Will it make the surface blotchy? (They told me it would at fibreglast.)
Thanks again, and I'll be watching your other thread!
DelawareDan
Eventually i will have to refinish my 79 Montauk, so i am trying to get some insight into the factors that i need to consider when deciding to how refinish.
I am curious why you decided to gelcoat rather than paint. From what i understand paints like Awlgrip are more durable than gelcoat and gelcoat is porous. given the difficulty in applying gelcoat and PVA described above i would think painting is the easier option. (i have no experience with using awlgrip so i have made a big assumption that it is easier than gelcoating, it may not be).
Now that I've looked into it more, I would agree essentially with what you said. It's easier to paint, even with Awlgrip or Imron, which are 2 part catalysed paints. Those paints are very durable and watertight. I would recommend Interlux Interprotect 2 part primer for below the waterline. And, of course, scrupulous surface prep.
Gelcoat boats do very well when they are trailered. If I were going to park the boat in a slip, I might do an Awlgrip paint job for above the waterline, and antifoul bottom paint over Interprotect for below.
If I get around to it, I'm going to post some pictures of the hairline cracks and blistering my boat has. Now that the bottom paint is ground off, it shows quite clearly, and it is extensive. I've discussed this it seems endlessly with a variety of experts and "experts" (sometimes it's hard to tell the difference!) and I still am researching, but I've GOT to get this boat in the water! I'm very close to deciding to grind all the gelcoat off the bottom, grind out a few epoxy repairs that I just did, and re-repair them with polyester resin and cloth. Then I plan to lay cloth over the whole bottom below the waterline, in polyester. If I had Derwd24's boat, I'd repair his bottom with epoxy, prime with something good, and bottom paint. But since I'm going to gelcoat, which is polyester, I'm going to bond the new layer with polyester. (It will take 38 inches X 6 yards of material.)
I'll get some argument that epoxy is better for repairs. The advice is this: epoxy has a better secondary bond, so it's great for repairs. A primary bond is chemical; a secondary bond is mechanical. When layers are built up in boatbuilding, they have primary bonds.
Regelcoating is a study in compromise. You're doing it backwards. Normally a mold is coated with PVA release, then the gel is sprayed on, then the layers of fiberglass are built up. You can't get a chemical bond regelcoating. But polyester resin bonds well to itself if the old surface is properly prepared, so I'm going to do that and be sure that I'll have no incompatibility with the gelcoat.
Mat is thicker than cloth, and is compatible with polyester (not with epoxy) but it's weaker than cloth, and being thicker, would add more weight to the boat. I think a single layer of cloth below the waterline will GREATLY help against cracking of the gelcoat surface while adding little weight. I'm going to start with the transom, doing the cloth and then immediately adding fairing filler to the remaining catalysed resin, then going over the cloth with a notched trowel for even distribution, and then flattening that out with a squeegee. If I think I can do that whole process before the resin kicks, I'll do a whole side of the remaining hull at a time. Otherwise, I'll lay the cloth, let it kick, sand and prep, then do the fairing filler. I'll ramp the filler up onto the topsides (it's a very small ramp!) and go over the cloth with this stuff, so that when I sand, I won't be cutting the fibers of the cloth. The filler makes the resin much more sander-friendly.
The remaining issue for me is whether this "hairlining" is caused by damp foam freezing and expanding. I'm just not sure that's what is occuring. I'd like to hear more discussion on this. It's quite difficult separating the theories from the realities. Above the waterline, I have an almost perfect gelcoat... 38 years old. A couple of hairlines by the bow eye, is all. And it's oxidized a little, but could be brought back, though there are some dings and scratches. That's part of why I'm gelcoating my baby. If Awlgrip were applied over a perfect surface 38 years ago, I doubt it would look as good as my topsides today. Just my opinion, of course.
But again, I'd paint with Awlgrip in certain situations. But I also like the idea of having a fresh factory-like finish, and I've done a fair amount of research, and think gelcoating is within my capabilities. Believe me, painting with Awlgrip is not easy, and for a perfect finish, one would have to wetsand it with 400, then 600, then 1000, then rubbing compound, then polishing compound. That's no different than what I'll have to do with the gelcoat. Plus I can spray all 6 coats one after another for a chemical bond, with no prep in between coats.
That's my logic anyway, and I would very much welcome any corrections, comments or even flames! Don't hold back on my account; I need all the help I can get. I realize that's more than you asked about, but I wanted to do an update anyway on my plans, in case others had comments.
Nothing like a Whaler.... look at the LINES on her!
Jeff, thanks very much. You're right; an excellent read! That guy obviously knows what he's talking about! Much of what he wrote confirms what I've been looking at, but I picked up quite a few great tips and details there!
jaemrich: The article responds pretty directly to your question:
The resulting finish and the nature of the gelcoat will far exceed a painted surface in terms of longevity and repair ability, but you'll see why painting is the less expensive alternative. Gelcoat is less expensive in terms of material costs, but that is outweighed in terms of labor costs... Over a 20 year period the gelcoat becomes more cost effective, especially when compared with Awlgrip on topside surfaces since there would be at least 1 if not more re-paint jobs needed.
jaemrich: The article responds pretty directly to your question:
Thanks - as the time to refinish gets closer I dive deeper into the subject. Can't wait to hear more on the re-gelcoating process and the results. keep the pics coming.
Nothing like a Whaler.... look at the LINES on her!
I'll second that. There is a lot of junk out on the water - sure they are shiney now but where will they be in 15 years - or 38 for that matter?
i am no expert on the issues of gelcoat vs awlgrip however i have been exposed to both while crewing on a yacht bound for antigua.
the yacht was on the hard in maine being refitted with a new teak deck as well as awlgrip for the mast, boom and spinniker pole. i asked both captain/crew and yard painters why use awlgrip over gelcoat or vise versa? (they all seemed to come to the same conclusion)
they said it depends on your use, if you are a small pleasure boat gelcoat makes sense because its more durable and can be patched with relative ease. if weight is an issue for racing or what have you than awlgrip is better as it is much lighter. they claim the downside to awlgrip is that it is very hard to fix scratches of any magnitude and have them match the rest of the hull.
dont take this as cast in stone as i am sure there are others out there that will disagree with me and my sources, but hope this helps shed a little light onto a complicated issue.
Here is an interesting reply to the article to which Jeff directed me. I posted a link to that article on my thread at fibreglast.com The guy who is responding does this stuff for a living, and seems to work a lot on bass boats with glitter and clear gelcoat. He's been very helpful and generous with his time, and I value his input. But here again you have two guys who are both doing it for a living, and their methods and opinions of what work best differ considerably:
I agree that was a good article. However, there are some things which contradict the way I was taught, so I feel I should address them, so nobody gets confused and throws their hands up in the air.
"Allow the gelcoat to harden for several hours between coats."
-I've never done it that way. I probably never will, and my foreman will not let a boat leave our shop that is not repaired to a very high standard. Waiting hours will obviously decrease the chemical bonding, and I suspect it may lead to cloudiness or porosity in the final product since that sticky film may be unable to find its way to the surface like it does when you spray all at once. Maybe that's one reason I've seen my share of bad repairs done by the other guys.
"The less you can thin it the better the gelcoat will be."
-This depends depends upon the job. For example, if it's a small repair, you can spray it real thin, skip to #1000 grit, buff it and be done with. If you spray even a large area with gelcoat that is too thick, your orange-peel will be much worse. I'd say just the opposite: You should thin your gelcoat as much as you can without making runs. Besides, more duratec turns low quality gelcoat into high quality gelcoat.
"Do not thin your gelcoat with acetone, MEK or lacquer thinner."
-Obviously do not thin with MEK-P, unless you want a fire. It's the catalyst, and it generates a lot of heat. Lacquer thinner? You've gotta be kidding! Uh, you can thin your gelcoat with acetone. It just leaves cheap gelcoat, well, cheap.
"Allow at least 24 hours for final cure & before sanding."
-Not necessary. In fact, if you catch it when it's still a bit soft, the orange-peel can be sanded out much more easily.
"Once you've reached the end of your sanding, the 1,000 grit will have brought your surface up to a dull luster. A course rubbing compound shouldn't be necessary and you may be able move to a fine compound like 3M Finesse-it."
-Don't skip the compound unless you go to #2000 grit. I guarantee, I would be able to find scads of #1000 grit scratches in gelcoat that wasn't buffed with compound.
I still say you should skip the wax, PVA, or anything like it, especially in clear gelcoat. I've seen too much porosity and cloudiness in bad gel. It's not pretty, and I suspect much it was caused by complicating the process with all that.
...Back to work!
Now the only thing I found in the article that I could argue with was that the author misspelled coarse. "A course rubbing compound..."
