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#1
posted to rec.boats.building
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Gellcoat (I think) flaking off
On Apr 8, 10:33*pm, wrote:
On Thu, 8 Apr 2010 09:44:19 -0700 (PDT), wheewhoo wrote: Any advice, opinions, etc welcome What size boat? *Can you flip it upside down to work on it? Look at thread " Peeling fiberglass surface" that was running a couple of weeks ago. Does your peeling look like this?http://s958.photobucket.com/albums/a...0Seas%20Skiff/ Rick Hi Rick, it is a 20ft boat, but access is ok to the effected parts. It does look similar to those photos, but my coating is much thicker, and is flaking off in much smaller parts, with only very small areas of fiberglass showing where pieces have fallen out. The surface looks more shattered than peeling, but that is due to the thickness of the coating I suppose. I'm thinking to just remove the coating, or gel coat if that's what it is, and seal it up again. A very gritty belt on a belt sander would do it I think. If this is a gel coat, is it normal to be so thick? Could this also be layers of paint applied over the years? When crushed the flaked pieces snap and are brittle. I suppose you are going to ask for a photo now |
#2
posted to rec.boats.building
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Gellcoat (I think) flaking off
On Apr 8, 10:33*pm, Phantman wrote:
On Thu, 8 Apr 2010 09:44:19 -0700 (PDT), wheewhoo wrote: Any advice, opinions, etc welcome What size boat? *Can you flip it upside down to work on it? Look at thread " Peeling fiberglass surface" that was running a couple of weeks ago. Does your peeling look like this?http://s958.photobucket.com/albums/a...0Seas%20Skiff/ Rick Hi Rick, it is a 20ft boat, but access is ok to the effected parts. It does look similar to those photos, but my coating is much thicker, and is flaking off in much smaller parts, with only very small areas of fiberglass showing where pieces have fallen out. The surface looks more shattered than peeling, but that is due to the thickness of the coating I suppose. I'm thinking to just remove the coating, or gel coat if that's what it is, and seal it up again. A very gritty belt on a belt sander would do it I think. If this is a gel coat, is it normal to be so thick? Could this also be layers of paint applied over the years? When crushed the flaked pieces snap and are brittle. I suppose you are going to ask for a photo now Well... yeah, a photo is worth 1000 words. But even a photo might not be enough. If you can actually see the resin and the glass though, then the gel coat is missing. So either it's flaking off now, or it was knocked off previously and somebody painted over the ding and now the paint is flaking off. Or possibly someone tried to patch it with Bondo or something and now THAT is falling off. Lots of possibilities I suppose. But without actually seeing it, it's tough to know. And even a photo might not show the situation clearly. You'll have to scrape around under there to figure out what layers are (or were) there, and if you're looking at a new situation or an old failed patch job. But sounds like you'll need to clean out the dings or whatever they are and then fill and fair the bottom. Then repaint with bottom paint if you're leaving it in salt water. Rick |
#3
posted to rec.boats.building
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Gellcoat (I think) flaking off
On Thu, 8 Apr 2010 15:32:24 -0700 (PDT), wheewhoo
wrote: On Apr 8, 10:33*pm, wrote: On Thu, 8 Apr 2010 09:44:19 -0700 (PDT), wheewhoo wrote: Any advice, opinions, etc welcome What size boat? *Can you flip it upside down to work on it? Look at thread " Peeling fiberglass surface" that was running a couple of weeks ago. Does your peeling look like this?http://s958.photobucket.com/albums/a...0Seas%20Skiff/ Rick Hi Rick, it is a 20ft boat, but access is ok to the effected parts. It does look similar to those photos, but my coating is much thicker, and is flaking off in much smaller parts, with only very small areas of fiberglass showing where pieces have fallen out. The surface looks more shattered than peeling, but that is due to the thickness of the coating I suppose. I'm thinking to just remove the coating, or gel coat if that's what it is, and seal it up again. A very gritty belt on a belt sander would do it I think. If this is a gel coat, is it normal to be so thick? Could this also be layers of paint applied over the years? When crushed the flaked pieces snap and are brittle. I suppose you are going to ask for a photo now If you can actually see the underlying fiberglass material, and you know that it is fiberglass then, if you want to fix it, you will have to at least sand the areas back until you know that you have reached some sort of solid foundation. The "blisters will need to be "dished out" with the, now, sharply delineated indents, sanded back to blend them into the remaining surface. You can then paint the repair area with activated epoxy resin (this wets out the area and ensures that you do have 100% epoxy coverage) and then fill the dished out area with epoxy filler made with epoxy resin and a thickener. Sand smooth, paint with epoxy high build primer and sand again, spray finish coat of two part polyurethane paint. Have a look at the WEST System web pages for more detailed information complete with pictures. .. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#4
posted to rec.boats.building
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Gellcoat (I think) flaking off
Hi guys, thanks for the replies.
So what I need to do is sand off the gelcoat (and whatever other layers are there), as I can definitely see the fiberglass where flakes have come away. Do I just need to prepare the bare (fiberglass) surface, and apply a new gelcoat? Or do I need layers of other stuff also? Lets say I have a large area of hull/keel that I have sanded back to the fiberglass. What are the steps I should take? Phantman mentioned bottom paint, and Bruce mentioned epoxy. Would it be epoxy, then gelcoat, then bottom paint? Thanks for the help! |
#5
posted to rec.boats.building
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Gellcoat (I think) flaking off
On Sun, 11 Apr 2010 11:13:54 -0700 (PDT), wheewhoo
wrote: Hi guys, thanks for the replies. So what I need to do is sand off the gelcoat (and whatever other layers are there), as I can definitely see the fiberglass where flakes have come away. Do I just need to prepare the bare (fiberglass) surface, and apply a new gelcoat? Or do I need layers of other stuff also? Lets say I have a large area of hull/keel that I have sanded back to the fiberglass. What are the steps I should take? Phantman mentioned bottom paint, and Bruce mentioned epoxy. Would it be epoxy, then gelcoat, then bottom paint? Thanks for the help! The basic task if to protect the underlying fiberglass from UV damage (a real threat in tropical climates) and water ingress which may take place over a longer period of time. There are two basic methods, to apply a gel coat or to paint, usually with an epoxy based paint. The gelcoat is much harder to apply and have a nice smooth shiny surface. The paint is much easier to apply but perhaps not as long lasting. Gelcoat Method. Grind/sand, the damaged areas back to a good solid surface. This surface can be either fiberglass or gelcoat but it MUST be a good solid surface. If gelcoat you must be certain that it is attached firmly to the underlying fiberglass. Once you have reached your base surface you must then "fair" the surface as smooth as possible as any craters, dips humps, etc. on the surface will be mirrored in the final finish. You can do this by grinding/sanding the surface until it is flat or you can build up the low spots with an epoxy filler using any of the harder, stronger fillers. Once things are fair you then sand with varying grades of sandpaper to about a 500 grip sandpaper. Gelcoat is nothing more then polyester resin with a coloring agent in it and comes in many colors. The mix also has a "wax" incorporated in it that when it is applied floats to the surface and causes the polyester to harden with a non-sticky surface. The gelcoat can be applied with a brush or by spraying but no matter how it is applied will probably not be the smooth, shiny, beautiful coating that you have envisioned. It needs work. Sand the gelcoat with progressive grades of sandpaper down to at least 1,000 grit and preferably finer. Once you have the surface as smooth as possibly then buff the surface to the required finish using a buffing wheel and polishing/buffing compounds as used for paint. If you did a good job it will be beautiful. Painting - Basically you do all the preparatory steps to get the hull smooth and fair and then apply two coats of epoxy resin to seal the hull. One method to avoid the "epoxy blush" problem is to apply the second coat of resin before the first coat is completely hardened. When it is no longer sticky but not hardened completely so that you can press your finger print into the epoxy apply the next coat. Finally after the last coat of epoxy (before it completely hardens) apply at least one coat of epoxy high build primer. Sand the hardened primer with about 400 grit sandpaper and do any touching up, sand again if necessary, and spray two coats of two part polyurethane paint. It will be beautiful if you did a good job. But don't kid yourself , either method is a substantial amount of work. The gelcoat considerably more work, but neither is a Sunday afternoon project. Cheers, Bruce (bruceinbangkokatgmaildotcom) |
#6
posted to rec.boats.building
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Gellcoat (I think) flaking off
On Sun, 11 Apr 2010 11:13:54 -0700 (PDT), wheewhoo wrote:
Hi guys, thanks for the replies. So what I need to do is sand off the gelcoat (and whatever other layers are there), as I can definitely see the fiberglass where flakes have come away. Do I just need to prepare the bare (fiberglass) surface, and apply a new gelcoat? Or do I need layers of other stuff also? Lets say I have a large area of hull/keel that I have sanded back to the fiberglass. What are the steps I should take? Phantman mentioned bottom paint, and Bruce mentioned epoxy. Would it be epoxy, then gelcoat, then bottom paint? Thanks for the help! On Mon, 12 Apr 2010 07:34:06 +0700, bruceinbangkok wrote: The basic task if to protect the underlying fiberglass from UV damage (a real threat in tropical climates) and water ingress which may take place over a longer period of time. There are two basic methods, to apply a gel coat or to paint, usually with an epoxy based paint. The gelcoat is much harder to apply and have a nice smooth shiny surface. The paint is much easier to apply but perhaps not as long lasting. Gelcoat Method. Grind/sand, the damaged areas back to a good solid surface. This surface can be either fiberglass or gelcoat but it MUST be a good solid surface. If gelcoat you must be certain that it is attached firmly to the underlying fiberglass. Once you have reached your base surface you must then "fair" the surface as smooth as possible as any craters, dips humps, etc. on the surface will be mirrored in the final finish. You can do this by grinding/sanding the surface until it is flat or you can build up the low spots with an epoxy filler using any of the harder, stronger fillers. Once things are fair you then sand with varying grades of sandpaper to about a 500 grip sandpaper. Gelcoat is nothing more then polyester resin with a coloring agent in it and comes in many colors. The mix also has a "wax" incorporated in it that when it is applied floats to the surface and causes the polyester to harden with a non-sticky surface. The gelcoat can be applied with a brush or by spraying but no matter how it is applied will probably not be the smooth, shiny, beautiful coating that you have envisioned. It needs work. Sand the gelcoat with progressive grades of sandpaper down to at least 1,000 grit and preferably finer. Once you have the surface as smooth as possibly then buff the surface to the required finish using a buffing wheel and polishing/buffing compounds as used for paint. If you did a good job it will be beautiful. Painting - Basically you do all the preparatory steps to get the hull smooth and fair and then apply two coats of epoxy resin to seal the hull. One method to avoid the "epoxy blush" problem is to apply the second coat of resin before the first coat is completely hardened. When it is no longer sticky but not hardened completely so that you can press your finger print into the epoxy apply the next coat. Finally after the last coat of epoxy (before it completely hardens) apply at least one coat of epoxy high build primer. Sand the hardened primer with about 400 grit sandpaper and do any touching up, sand again if necessary, and spray two coats of two part polyurethane paint. It will be beautiful if you did a good job. But don't kid yourself , either method is a substantial amount of work. The gelcoat considerably more work, but neither is a Sunday afternoon project. Cheers, Bruce (bruceinbangkokatgmaildotcom) Took the words right out of my mouth ^^^^ ;-) .... and I vote for the gelcoat method :-) Rick |
#7
posted to rec.boats.building
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Gellcoat (I think) flaking off
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#8
posted to rec.boats.building
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Gellcoat (I think) flaking off
After writing that I happened to meet a mate who does this kind of stuff as a business. He was showing me some very pretty "Biminis" for a catamaran that he has just built with glass over foam. I asked him of it was gelcoat or paint and he went into details about gelcoat. He is now building these "bimini" or cockpit covers for Cats one right after another. He says that they are actually lighter then canvas and stainless, as less stainless is used. But he now uses gelcoat in preference to paint as gelcoat is good over polyester and less good over epoxy so he can build these things using polyester. The gelcoat hardens "right now" as apposed to " sometime tomorrow " for paint thus he has less idle time and he can build them faster. He thins the polyester gelcoat with "Styrene???" and sprays it but did comment that you didn't want to delay cleaning the gun :-) He recommends sanding to whatever grade wet or dry paper you can get 1,000, 1500, 2,000, etc. and then buffs. As far as the finish he gets, some of his stuff has been installed on million dollar boats and the owners were happy with it:-) He recommends paint over epoxy and gelcoat over polyester and is pretty much using it on everything that he does now. Cheers, Bruce (bruceinbangkokatgmaildotcom) Bruce, What does this bimini look like? a canvas and frame bimini or a smooth hardtop? Sounds very interesting. |
#9
posted to rec.boats.building
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Gellcoat (I think) flaking off
Thanks, Bruce, for the lenghthy and detailed reply, much
appriciated I need to work out which product to go with I suppose. I was looking at this on eBay: http://cgi.ebay.co.uk/Epoxy-Resin-Ha...item334f06460f How suitable would that be for my application? If not, that seller has a "resin shop", can you see anything in his shop that would do the job? Or if i go with a gelcaot, he has that too: http://stores.shop.ebay.co.uk/resinshop__W0QQ_armrsZ1 Thanks again |
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