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Old 02-06-2011, 11:31   #31
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Re: Keel Repair - PICS

Repaired a hole in the encapsulated ballast keel of my boat last fall.Very similar. Hit a rock or maybe a buoy weight when Lake Champlain was near historic lows last summer. Used West epoxy and ALL heavy roving for the repair, 12+ layers in all and fairing, well over an inch of solid glass, feathered out a good 16". Forget mat. It is difficult/impossible to work overhead and has little strength. Roving is very tough and easier to work with. The hull in your pix looks like about 3/4" thick?? You need 12:1 taper around the hole. Just mark out a radius around the hole and start grinding. Largest piece first when you start glassing. You can cut all your pieces before you start and lay on as many as will adhere without sagging. Toward the last few layers, get a flexible piece of wood or aluminum to eyeball fair curves. You want to get it close with the glass so as to avoid a lot of filler/fairing at the end. I did four layers at a clip, sanded, then the next. West's website has all the info. on how to do it. Moisture needs to be completely gone of course. It's really not a difficult repair so don't be too upset except at the guy who sold you the boat without pointing this out. In grinding off the bottom paint I discovered that I was not the first to do this job in the same general spot and that the previous repair was not very good at all, so it actually amounted to an improvement.

Invest in a good organic vapor mask, disposable Tyvek jump suit(s), and some heavy rubber gloves. Light latex/nitrile gloves are not nearly durable enough for this kind of thing.
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Old 02-06-2011, 12:33   #32
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Re: Keel Repair - PICS

You can check out my profile pics to see what I had to deal with. 100 times worse than yours. Here is a few tips.
I found I needed 25 layers to get 1/2 thickeness can't remember weight of cloth.
I tried doing 10 layers at a time, bad idea it all slumped off in a wet soon to be solid heap. Max 5 layers at a time. To support don't be afriad to attach wet mat with screws.
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Old 02-06-2011, 12:54   #33
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Re: Keel Repair - PICS

I'm not a professional, just an amateur whose too dumb not to take on major projects and learn as I go. I've built a boat from a bare hull, am rebuillding one, and beat the crap out of a couple. In building, rebuilding the boats, I've changed the position of bulkheads and furniture very occasionally. Found that sometimes, not always, could rip the fiberglass tabbing off the hull by brute force flexing the plywood panel. The tabbing didn't come away completely cleanly but much of it did. When I started torqueing the plywood, expected the tabbing to break away from the plywood, not from the hull. Pleasantly surprized myself the first time I did it as I didn't want to have to cut and grind all that tabbing. Didn't always rip iaway mostly clean but much of it did come away from the hull.

I sailed the hell out of my first boat, a Columbia 26, here in Hawaii. The boat was fairly thin skinned, would pound going to weather and probably oil canned. After one too many trips going to weather across the Molokai Channel, the main bulkhead tabbing popped off the hull and left the plywood dangling. Hey, it was a '70s Columbia and Columbia was not noted for rivaling Hinckley in construction quality. Maybe the factory FRP guy had a bad day. I'd laminated the bulkheads into the boats I'd built and they had been done properly, however. Polyester resin will stick to previously laminated resin but not nearly as well as Epoxy. In this case, we're talking a lower keel area that's likely to get severe abuse if the boat is actively sailed. For me, I'll stick with Epoxy.

As far as time involved, it would probably take me more than two days 'cause I'm just damn slow. Have done a couple of repairs on a probably thicker hull than this and it only took me a day to laminate it up. These were smaller repairs in area but not in thickness which is really the controlling factor, however.

I will grant you that naked matt is hard to work with. Don't remember ever doing it with polyester but have with epoxy. You want to apply the matt, wet it out and then quit messing with it, If you don't, the fiberglass strands will lift and slide around leaving you with a mess that you'll have to grind smooth, btdt. Laminating with a matt/roving facing mostly solves this problem. Forget about where I read about the binder problem with Epoxy but if untrue, someone is spreading misinformation. If true, really shouldn't be a problem unless you have some really old matt lying around. I did but didn't want to waste the time testing the binding with epoxy.

I tend to be a perfectionist and working on my own boats. I've had two boats that've tried to fall apart at sea, run aground and crunched a bit of coral and sailed 5 figure miles in total. I like things done in a way that I know from best experience will hang together. From experience, it's a bit nerve racking when things go to **** too far offshore to swim to the beach.

Just out of curiosity. If matt is not important in a laminate, why do they go to the trouble making the cloth/roving and matt composite material?? You can build up thickness fairly quikcly with woven roving. Trying to get substantial thickness using cloth takes a lot of laminates.

If you don't want to lose feel and flexibility of nitrile/latex gloves. put on 3-4 layers of these gloves. As they tear and/or get messed up, tear them off and keep working till you get down to the last layer. In most instances, you'll get the job done before running out of layers of glove.
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Old 02-06-2011, 13:13   #34
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Re: Keel repair - PICS

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Originally Posted by allanpeda View Post
First I heard of polyester being comparable to Epoxy for bonding to older pre-existing polyester. In the factory, one would presume the bonds would be polyester to freshly cured polyester.

This link explains why.
My 1965 Rhodes Reliant is a polyester/woven roving/mat hull layup. The multiple, alternating, mat and roving, 18" tabbing of the hull and deck joint is epoxy, as specified on the drawings by Rhodes.
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Old 02-06-2011, 13:24   #35
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Re: Keel repair - PICS

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My 1965 Rhodes Reliant is a polyester/woven roving/mat hull layup. The multiple, alternating, mat and roving, 18" tabbing of the hull and deck joint is epoxy, as specified on the drawings by Rhodes.
Exactly. I was emphasizing the utility of the Epoxy. Poor writing style on my part.
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Old 02-06-2011, 14:40   #36
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Re: Keel repair - PICS

Matt is used because it mushes around and fills voids enhances bonding surface. So the same reason we dont want to use it is what its intended purpose is. Wether its epoxy or polyester i never it layup matt without cloth on top. DBM. Thickening the resin has a similar effect. polyester comes in 2 diffferent breeds finishing resin has a wax added to enhance the finish and allow for sanding. Laminating resin does not have the wax. Laminating to finishing resin will result in a bad bond. Just a few notes to add
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Old 02-06-2011, 16:30   #37
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Re: Keel Repair - PICS

A lot of what looks like mat in some boats is actually sprayed chopped strand. It builds up really quick and was a pretty good production method when done right. I used to watch the poor guys who worked at a boat factory next door to where I kept my clam boat do this for 8 hours a day. Yech! It doesn't have as good a directional strength as hand laid mat.

S/V_Surya, I know what you mean about sagging. I lost about 1/2 gallon of resin trying to put on too many layers at once. Once it starts to go it's an awwwwwwwwww $^#t.

Using all heavy roving makes the most sense to me because you can really control both the saturation and thickness. It is much thicker than cloth, which I suppose would work too with LOTS of layers. The roving does not ball up and move around like mat but has enough flexibility to move where needed. If you grind to the 12:1 ratio, feathering outward from whatever shape the hole is, you can then cut the pieces of roving in exact decreasing incremental pieces ahead of time. Going out say 16", decreasing your outline by 1" on every layer, you are building up approx. 3/32" on each layer. The center of your void will be built up by approx. 1 1/2" . This method worked out really well on the job described in my last post and there was virtually no fairing when it was done. A layup like this out of heavy roving, criss-crossed is extremely strong. It also matched what was there to begin with. Looked like Pearson used mostly roving with a little mat in the top layer or two.

The most important part of the operation IMO is the first layer being very well contacted on a clean surface. I primed the entire area with epoxy first, let it cure then sanded it roughly before the first layers of glass and was satisfied that I had a good bond, much bigger than the holed area. I used 60 grit for all the sanding until the top fairing layer.

Next year the plan is to epoxy-coat the entire hull and maybe even lay on a thin, flexible cloth to cover the gelcoat spider cracks on the old hull. I hope the old girl appreciates all this work!
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Old 03-06-2011, 10:23   #38
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Re: Keel Repair - PICS

"...could rip the fiberglass tabbing off the hull by brute force flexing the plywood panel..." Yeah, when you think about it...the last coat inside the bare hull has the wax in it the resin to keep it from being sticky forever. Then when they tab the bulkheads etc in...if they dont grind it first...it aint gonna stick!
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