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Old 31-05-2011, 01:14   #16
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Re: Keel repair - PICS

Believe all the matt now available has binders soluble in Epoxy. Older matt may not, so be sure what you buy is compatible with Epoxy Resin. Other than that, it makes no difference whether you use epoxy or polyester resin. Fiber Glass construction gets it strength from the fibers that are held in place by the resin. The first boats built with resin bonded fibers used cotton cloth. You can make a decent boat ouf of old T shirts. Go to West Systems web site. They have a lot of how to information.
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Old 31-05-2011, 01:25   #17
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Re: Keel repair - PICS

Never use matt of any kind in an epoxy layup. Epoxy will instantly dissolve the starch that is the only thing holding the matt together, causing it to turn into a sticky mess on you. If you are using DB 1708 with stitch matt and you encapsulate all the matt it can work out ok, but that only works on huge lams with little or no relief cuts. Matt and epoxy do not agree.
I also would reccommend staying away from carbon or kevlar in repairs. Kevlar because it cannot be ground for fairing, it turns into a fuzzy surface if you do, and carbon because it wont really do anything for you on a repair of this size, costs a lot, and is super itchy when ground. Way worse than regular glass. Stick with polyester iso resin, not ortho; or vinylester. Then you can bang it out quick. If you go with epoxy you have to fair with epoxy as well. Finish with some interlux 2000 and bottom paint and off you go. Good luck!
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Old 31-05-2011, 02:59   #18
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Thin on the ground?

From the look of it the bottom and front of the keel may have been a bit on the thin side right from the start. If it were mine I'd be tempted to add a fair bit of thickness (say 1/2") to the bottom (and front?) of the keel. Not that my boat would ever touch the bottom.

A few extra layers on the side running half way up and tapering in may be desirable, not so much now but as you crack on the genoa into a stiff breeze...

It goes without saying that it must be completely dry. As you abrade back to good glass there may be a few weep holes. Maybe dig them out and a bit of wet set mastic or epoxy to stop any weeping and then get it all perfectly dry.

There could be more voids void under the fibreglass. This would be a good time to make sure they've all been filled.

Complete throw away overalls, full face filter mask, boots, the works in safety gear are in the cards.

Do make sure the boat is well propped up. Having it fall on you could spoil your day.
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Old 31-05-2011, 10:09   #19
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Re: Keel repair - PICS

yes, steel punchings...usually round or square rems about 1/2" to 1" were used a lot in NW fishing boats too for ballast...encapsulated in cement... The key to this repair appears to be drying it out. The rest aint brain surgery... exotic mat etc is not needed. I get the impression this is a small boat (looks pretty thin glass for a keel!) maybe it was a give away?
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Old 31-05-2011, 10:29   #20
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Re: Keel repair - PICS

matt has no strength--was used in hand laid hulls as a filler between layers of roving... use roving for strength, and use more than one layer of it. epoxy soak it well--- let the keel dry for a while before fixing--should probably take a month to dry if has been in water-- less time if has been on hard. goood luck. should fix ok, if done right-- clean well with sanding the keel to the fiberglass and use mek to remove any waxy stuff from original lay up
remember to overlap more than just a couplafew inches.....
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Old 31-05-2011, 11:03   #21
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Re: Keel repair - PICS

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Stick with polyester iso resin, not ortho; or vinylester. Then you can bang it out quick. If you go with epoxy you have to fair with epoxy as well. Finish with some interlux 2000 and bottom paint and off you go. Good luck!
That would be my thinking use dbm or matt and roving with one of your suggested resins. you could still fair with epoxy and an additive or vinyl ester filler.
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Old 31-05-2011, 11:18   #22
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Re: Keel repair - PICS

Sorry, I should have said cloth not matt. If it's been in salt water you should hose it out good before drying. A small A/C unit with a plastic tent will get it the best. Just air drying will likely leave a lot of moisture in there.... hard for it to escape... maybe a vacuum hose pushing warm air through there forcing moisture out??
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Old 31-05-2011, 11:49   #23
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Re: Keel repair - PICS

Wow 22 posts with everything from lawyers to carbon fiber and the OP appears silent...Gotta love CF.
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Old 31-05-2011, 16:59   #24
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Re: Keel repair - PICS

Hi, I am happy to have found another great FORUM
The deal is done and this is preety much the only deal in town. So I either fix it of I have to wait some years $$$ for a better boat.

1-The boat is a Tur 80. [LINK]
2-Its now out-of-the-water for almost 2days and the bottom is still wet. (But no water inside the boat at all. It looks dry and clean inside.)
3-The keel is iron, although I dont see any rust. (no orange liquid coming out). Maybe it will appear after some days with the oxidation.
4-The hole is not actually a hole because the BLACK you see on the picture is the Iron keel. So its just there!

Thanks for the input. I have to digest all that info and I will come back with more info soon.
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Old 31-05-2011, 17:57   #25
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Re: Keel repair - PICS

Not the end of the world, as long as you understand that you must first grind away all the bad stuff before you can replace it with good stuff. Don't just patch! Grind first, then patch.
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Old 01-06-2011, 13:48   #26
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Re: Keel repair - PICS

I'd say dry it as best you can, do good fibreglass repairs and use it. If a little moisture is in there....it will probably never be known unless you keep it 20 years!
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Old 01-06-2011, 22:08   #27
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Re: Keel repair - PICS

I agree with the grinding away all damaged fiberglass. You will see more of the iron keel after that. Use Ospho to "prime" it.

Measure the thickness of the current fiberglass in that area. You have to bevel at 12:1, meaning that if you have 0.5" thick fiberglass, you need 6" of bevel around the damaged and cut away area.

After all the grinding/cleaning/drying is done, start the repair like this:

- use epoxy, not polyester. You want a molecular (primary) bond for high strength which only epoxy can give you here.

- brush epoxy onto the iron keel and bevelled edges. Then take a stainless steel brush and brush the wet epoxy "into" the iron keel. This treatment promotes adhesion to the iron.

- wait about an hour so that the epoxy starts gelling. Now put fiberglass cloth over the patch area and cut it so that it touches the bevelled edge for 2-3". immediately brush epoxy onto the cloth to wet it out, until it turns transparent. do this again and again with 30 minute - 1 hour intervals to fill up the weave of the cloth. You can thicken the epoxy to a syrup consistency to make this easier. Use colloidal silica filler (=cabosil) for that and a roller.

- now put woven roving over the cloth and cut it so that it covers the bevelled edge for all but 1". Fill up the weave again. If you need multiple layers of woven roving to get the thickness of the laminate, cut the first layer smaller... every additional layer must be bigger than the previous one.

- end with another layer of cloth. On top of that, do a 90% accurate fairing with epoxy + colloidal silica mix (peanutbutter consistency). This gets rock hard. Use a grinder to shape it where needed. Let cure overnight and wet sand it. Now you can do final fairing with a light filler like micro-balloons or better West System Microlight.

- Sand & wet sand until satisfied. Paint with anti fouling.

ciao!
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Old 02-06-2011, 02:25   #28
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Re: Keel repair - PICS

Matt is a necessary part of any resin/glass layup. The matt adds rigidity and cuts down on the resin/glass ratio. Some people claim that the old thicker hand laid hulls are less strong than the newer thinner laminates. The old layups have a high resin ratio to glass fiber content. The new laminates are made with infused fiberglass and/or are often vacuum bagged which makes for a better saturated, less resin and thinner laminate. The reason these newer laminates are supposedly better is resin is brittle and if there is too much resin in comparison to fiberglass, the laminate can crack and actually be structurally inferior. The matt cuts down on the resin/glass ratio by filling the uneven surface of the roving cloth with resin coated fiberglass strands rather than just resin. Don't use thickened epoxy in place of matt. You can use thickened epoxy as a fairing but not in the laminate unless you have a good reason. A good reason if you are laminating a radius and the first layer is unfair and lumpy. You may need to use a layer of thickened epoxy to make a smooth radius.

Matt makes the layup stiffer by separating the roving layers from each other. That small separation allow each roving layer to act like each side of an I beam against the previous roving laminate. That makes the laminate way stiffer than if the separation wasn't there.

Many summers ago I bought a new Morgan that I took delivery of at the factories yard in St. Petersburg. The hull was laid up in two halves. The schedule layup called for roving and chopper gun matt. One side was laid up according to schedule. The other one had a serious problem with the chopper gun. Either the gun malfunctioned and the operator didn't see that it wasn't delivering any chopped fiberglass along with the resin or they just didn't bother laying any of the chopped fiberglass between the laminates of roving. By the time I'd sailed the boat from St Pete to Norfolk, on the side without the chop/matt, you could see every tabbed bulkhead from the outside of the hull and that side of the hull flexed significantly in a seaway. Without the random strands of chopped glass/matt, that side seriously lacked rigidity. The side with the chop/matt looked normal and was stiff. BTW, both sides supposedly had the same number of layers of roving.

Polyester resin does not stick all that well to old laminates. I've ripped newer polyester tabs clean off old laminates. The new laminate just didn't have a very strong bond with the old laminate, despite that the old surface having been ground and chemically cleaned before the new laminate went on. The polyester resin actually stuck better to the wood than it did to the old laminate. Epoxy will bond with the old laminate stronger than the old laminate has with itself. Epoxy is also waterproof so it acts as its own barrier coat.

Matt has a resin binder to make it possible to work with. Without the binder, you'd just have a pile of fiberglass strands. Matt used to be made with a binder that dissolved in polyester resin as that was pretty much all the resin was around. Then the Gougeon Brothers polularized epoxy and they had to change the binding agent. The newer matt uses a binder that dissolves in both polyester and epoxy resin. The binder has to dissolve so the individual fiberglass strands can 'flow' into the underlying surface. It is a lot easier to work with matt that has been sewn to a cloth or roving backing. You can easily work with matt separately if you lay cloth down on a board or butcher paper, put the matt on top and wet it out on the board/butcher paper. Then you can pick up the wetted out cloth/roving that will hold the matt in place and put it in position matt side down. If it's easier for you to work with, you can do the same thing laminating in place by laying the matt onto a resin wetted surface, putting cloth or matt on top and then wetting out the sandwich. When you are laminating over a void, the first layer should go all the way to the outer edge of the ground taper of the old laminate. Each successive laminate should be slightly smaller allowing for the taper ground into the old laminate.

Be careful working with epoxy, its a strong skin irritant. My last epoxy job involved working upside down in a small lazarette. I tore my latex gloves early on but forged on because it was so hard to get in position to do the lamination. Cleaned up with alchohol soap and water as soon as I was done but that didn't do the trick. The outer layer of skin on my hands peeled off over the next week or so. It's the first time I've had a problem with epoxy but it's also the first time I worked without gloves.
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Old 02-06-2011, 10:55   #29
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Re: Keel repair - PICS

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Matt is a necessary part of any resin/glass layup. The matt adds rigidity and cuts down on the resin/glass ratio. Some people claim that the old thicker hand laid hulls are less strong than the newer thinner laminates. The old layups have a high resin ratio to glass fiber content. The new laminates are made with infused fiberglass and/or are often vacuum bagged which makes for a better saturated, less resin and thinner laminate. The reason these newer laminates are supposedly better is resin is brittle and if there is too much resin in comparison to fiberglass, the laminate can crack and actually be structurally inferior. The matt cuts down on the resin/glass ratio by filling the uneven surface of the roving cloth with resin coated fiberglass strands rather than just resin. Don't use thickened epoxy in place of matt. You can use thickened epoxy as a fairing but not in the laminate unless you have a good reason. A good reason if you are laminating a radius and the first layer is unfair and lumpy. You may need to use a layer of thickened epoxy to make a smooth radius.

Matt makes the layup stiffer by separating the roving layers from each other. That small separation allow each roving layer to act like each side of an I beam against the previous roving laminate. That makes the laminate way stiffer than if the separation wasn't there.

Many summers ago I bought a new Morgan that I took delivery of at the factories yard in St. Petersburg. The hull was laid up in two halves. The schedule layup called for roving and chopper gun matt. One side was laid up according to schedule. The other one had a serious problem with the chopper gun. Either the gun malfunctioned and the operator didn't see that it wasn't delivering any chopped fiberglass along with the resin or they just didn't bother laying any of the chopped fiberglass between the laminates of roving. By the time I'd sailed the boat from St Pete to Norfolk, on the side without the chop/matt, you could see every tabbed bulkhead from the outside of the hull and that side of the hull flexed significantly in a seaway. Without the random strands of chopped glass/matt, that side seriously lacked rigidity. The side with the chop/matt looked normal and was stiff. BTW, both sides supposedly had the same number of layers of roving.

Polyester resin does not stick all that well to old laminates. I've ripped newer polyester tabs clean off old laminates. The new laminate just didn't have a very strong bond with the old laminate, despite that the old surface having been ground and chemically cleaned before the new laminate went on. The polyester resin actually stuck better to the wood than it did to the old laminate. Epoxy will bond with the old laminate stronger than the old laminate has with itself. Epoxy is also waterproof so it acts as its own barrier coat.

Matt has a resin binder to make it possible to work with. Without the binder, you'd just have a pile of fiberglass strands. Matt used to be made with a binder that dissolved in polyester resin as that was pretty much all the resin was around. Then the Gougeon Brothers polularized epoxy and they had to change the binding agent. The newer matt uses a binder that dissolves in both polyester and epoxy resin. The binder has to dissolve so the individual fiberglass strands can 'flow' into the underlying surface. It is a lot easier to work with matt that has been sewn to a cloth or roving backing. You can easily work with matt separately if you lay cloth down on a board or butcher paper, put the matt on top and wet it out on the board/butcher paper. Then you can pick up the wetted out cloth/roving that will hold the matt in place and put it in position matt side down. If it's easier for you to work with, you can do the same thing laminating in place by laying the matt onto a resin wetted surface, putting cloth or matt on top and then wetting out the sandwich. When you are laminating over a void, the first layer should go all the way to the outer edge of the ground taper of the old laminate. Each successive laminate should be slightly smaller allowing for the taper ground into the old laminate.

Be careful working with epoxy, its a strong skin irritant. My last epoxy job involved working upside down in a small lazarette. I tore my latex gloves early on but forged on because it was so hard to get in position to do the lamination. Cleaned up with alchohol soap and water as soon as I was done but that didn't do the trick. The outer layer of skin on my hands peeled off over the next week or so. It's the first time I've had a problem with epoxy but it's also the first time I worked without gloves.

The binder in mat is starch and always has been. The problem with epoxy and mat is not that the binder wont dissolve in epoxy, but just the opposite. It takes about ten minutes for the styrene in poly resin to dissolve the starch in the mat, giving you that long to work with it before it turns into a ball of goo on you. Epoxy resin dissolves the starch instantly, making stitch mat your only option for epoxy. And, as I stated earlier, if you've made any relief cuts in your stitched product you'll have exposed mat that will be a problem. Better to stay away from mat and epoxy. I've built several large boats by famous designers like Carl Schumacher which had no mat in their epoxy layups whatsoever. And to say that poly resin doesn't mechanically bond to poly resin well is crazy. If that was true most boats would just fall apart, as thats how all sorts of secondary bonds are done in the factory. I've repaired hundreds of boats using poly, above and below the waterline, major and minor. All of our work gets a ten year warranty and I've never had someone come back for a failed repair. Poly is fine for this and would be much faster and cheaper. With epoxy you have to wait for cure times. I'd do this job completed in 2 days, except for coating...
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Old 02-06-2011, 11:15   #30
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Re: Keel repair - PICS

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... And to say that poly resin doesn't mechanically bond to poly resin well is crazy. If that was true most boats would just fall apart, as thats how all sorts of secondary bonds are done in the factory....
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.
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