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Old 22-03-2011, 14:33   #1
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Question Fiberglass Repair

I just bought a 27' Aloha fractional sloop but it's got a bit of damage that I need to repair before I can put it in the water. I've never done fiberglass work before and so far I've mostly just done some reading online. While I've seen a bunch of how-to's I'd like to get some specific recommendations for my boat. I've attached a pic of the damage, it occurred from another boat at the marina getting out of its slip and hitting this boat.

So far my plan based on what I've read is:

1. Cut away the damaged fiberglass on the deck.
2. Reinforce the hull from the inside with fiberglass and repair the gel coat where it's cut.
3. Create a foam molding in the shape of the deck.
4. Use an angle grinder to create an indentation on the underside of the deck where I will be attaching the new fiberglass.
Now comes the tricky part:
5. Lay fiberglass on the underside of the deck and over the lip of the hull and use the foam molding to shape it.
6. Glue a new wooden core to the old wood. (tips on how to do this effectively would be appreciated)
7. Apply fiberglass over the wood core.
8. Sand the fiberglass so it's smooth and then apply gel coat. Not sure if a barrier coat is required first.

So far that's the plan but I would really appreciate anyone that could either give me some advice or point me in the direction of a good resource.

Thanks!
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Old 22-03-2011, 14:56   #2
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Re: Fiberglass Repair

Everything you need to know should be in here (187 page manual):

http://www.westsystem.com/ss/assets/...aintenance.pdf

More links to reference materials:
WEST SYSTEM | Use Guides

This technical info, with the exception of mix ratios and brand-specific product names, pretty much applies no matter if you use West System, System Three, Raka (I use Raka because of cost - bought my first West epoxy in 1981, then switched to System Three when it was new, then to Raka when System Three started thinking too much of their products...).

Most brands have tech advisors who will talk with you. Be careful accepting tech advice from just anyone online... (like me ).

If you need specific advice after studying up, ask here.
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Old 22-03-2011, 15:06   #3
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Re: Fiberglass Repair

not a very difficult repair apart from removing the alloy toe rail.

personally if the toe rail runs the whole lenth of the boat i would cut out the section where the repair is needed.

grind out all the damaged glass,and feather about 3' into the good glass.

run a batton along the line where the hull deck joint terminated,using self tapping screws into the hull.

using 450 gm chopped strand mat,and polyester resin,progressively lay up untill the required thichness is achived.

fair using grp auto body filler, sand and refair untill uniform finish.

gelcoat,fair,gelcoat,fair untill uniform.

remove batton,fair,apply last gelcoat

replace straightened toe rail.

sand hull ,fill,sand and respray
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Old 22-03-2011, 15:11   #4
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Re: Fiberglass Repair

Gracias, I'm actually in the process of reading that manual right now. It gives the general repair process but doesn't say give any specific advice on how to do what I need to do. The process it gives for repairing a core assumes that either the top or bottom skin is still intact which is not the case here. As I said above I think I need to replace the bottom skin with a foam mold, replace the core, and then replace the top skin. I'll definitely contact some of these companies to see what kind of advice they can give me.
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Old 22-03-2011, 15:15   #5
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Re: Fiberglass Repair

Yeah, that damage looks a bit severe to just get a quick opinion here. It appears that your toerail is also bent and that will need to be addressed as well. I don't know where you're located but where I am at the pro's don't usually mind giving some advice to DIY folks. Of two friends, one recently found a large crack in the rudder. After looking at it, I told him how I would approach it. He got a free second opinion from the local pro. (It happened to match mine ) but he did the work himself.

My other friend found some rot around his chainplates; the pro told him what to do, again for free. In his case, after starting, he decided the work was a bit beyond him so he paid the pro to do the major part and then did all the finish up work himself. Maybe not as inexpensive as doing the job totally by himself but he still saved a bundle and now has more faith that his chain plates aren't going to get ripped out.

Something to consider,

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Old 22-03-2011, 15:24   #6
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Re: Fiberglass Repair

I just did a similar but smaller repair on the the stern of my boat. Ground out all the bad glass which left a bit of daylight showing into the lazarette. Went inside the lazerette, roughed it up a bit and then laid FabMat on the inside from about 5" under the deck and bending down onto the transom. Waited for this to go off as it acted as a backing for the glass work on the outside. Laid a slurry of thickened epoxy along the area to be repaired then immediately laid on a layer of FabMat. The slurry filled the irregularities in the interior glass work and made it relatively easy to form a nice radius matching the rest of the hull to deck joint. Took a bit of massaging to get the curvature right between hull and deck but it came out quite good. Once it had stiffened up laid on successive layers of FabMat till it was built back up to the original thickness. Left it overnight and went back the next day and laid on a light slurry of expoxy fill material to smooth out the indentations in the FabMat cloth. Ground everything smooth with a Milwaukee sander/polisher fitted with a foam pad and 80 grit sandpaper. Still waiting to repaint the entire hull with AwlGrip.

Use epoxy not Polyester resin. Polyester just does not stick well enough to old laminates for such a high stress area. Be careful not to get epoxy on your skin. My gloves came apart fairly quickly working in the Lazarette but forged on to get the job finished. Despite cleaning the expoxy off after I got out of the Lazarette ended with all the skin on my hands sloughing off for the next couple of weeks.
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Old 22-03-2011, 15:32   #7
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Re: Fiberglass Repair

atoll - Why is removing the toe rail that difficult? I had planned to do it this Saturday and only alloted a couple hours. I'm not really following your instructions. It sounds like you are describing repairing the hull but not the deck, could you please be a little more specific?

cabo_sailor - The previous owner got a quote from the marina of $3000 to fix it. I actually talked with the repair guy before I bought the boat and he just gave me a very basic idea of what would be required. I'm hoping I will run into him at the marina once I've read up a little more on fiberglass repair.

I've included a picture showing the scope of the damage.
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Old 22-03-2011, 15:44   #8
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Re: Fiberglass Repair

atoll - Why is removing the toe rail that difficult? I had planned to do it this Saturday and only alloted a couple hours. I'm not really following your instructions. It sounds like you are describing repairing the hull but not the deck, could you please be a little more specific?

i think you will find that taking off the toe rail is quite difficult,as this is what holds the hull/deck together.especially if it is through bolted.

also resealing it when putting it back can be a challenge.

have done these types of repairs many times on a proffesional basis.
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Old 22-03-2011, 16:09   #9
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Re: Fiberglass Repair

After removing all hardware in the way, including toerail (and headliner and/or other interior items if applicable), cutting/grinding/removing all damaged glass and core, and grinding 8:1 or 12:1 scarphs on all glass edges, you are correct in the idea of needing a "mould" to hold up the first layer of glass. I have used anything that will hold it up, from tape and cardboard, to elaborate pieces of foam and plywood, some of which have then been left in the repair. ETA: Anything that can hold the first layer is OK.

You might try some thin (2 or 3mm) ply (or "door skin") under the deck (interior), cut to fit the side hull curve, covered with thin plastic like food wrap or plastic drop cloth material (to prevent epoxy from bonding to it) and held/sealed in place with either masking tape and/or duct tape. Make another piece if needed for the hull side as well, depending on how much of that is damaged and must be repaired.

After the first layer or two of glass is in and cured (from the exterior/top - its not meant to fully bond to the scarph, being on the 'wrong' side for that, but merely to support the 'real' laminations), remove the mold - it should peel right off. Then you have a start on your inner skin and the rest of the layers can be added to the interior to make the correct thickness and properly complete the bonding with the interior scarph.

Then you can add core material as needed from the top - usually plywood, cut into 2" square blocks if needed to fit curves, bedded into the repair area in a medium density bog (for a repair of that size it is not necessary to use anything special like balsa or foam...). Screw the core into the new lams if you like, or from under. When it sets, remove screws and fill holes with bog as part of the fairing process prior to adding the outer lams.

Grind/fill/grind core to make a nice fair, solid surface for your outer lams, and then complete outer laminates.

Then it's just cosmetic fairing, using low-density bog, as outlined in the manual, then painting.

I'd not mess with adding gel coat unless you have experience and can easily match the colors. I use System Three WR155 high-build two-part epoxy sanding primer (water reducible), and Sys3 WRLPU (two-part, water reducible LPU - aircraft and marine grade linear polyurethane). You can save money by skipping the primer if you don’t need a perfect finish... If you want to avoid expensive high-tech coatings all together, maybe go with Brightsides or similar one pot paint.

**!! BE AWARE that the dryers in alkyd based paints (like Brightsides) are neutralized by the amines in the epoxy and they will not dry but will remains a gummy mess. Use a proper primer between epoxy and alkyd based paints!!!

It is my understanding that epoxy has been the standard resin choice for many years (decades) now to repair production hulls originally made from polyester resin.

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Old 22-03-2011, 16:22   #10
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Re: Fiberglass Repair

BTW: To determine the number of layers needed as you go, each time you add a layer of glass to the repair, add a layer of the scrap cloth to a 6"x6" "test laminate" on a piece of plastic wrap on your work table or where ever.

That way, when you think you might have enough glass layers on the repair, you can cut the edge of the test patch and measure the thickness to see if it is greater than or equal to the laminate you are repairing...

This can also be done after the fact if you counted the layers on the repair as you added them, and then can make a similar test patch wiht the same number of layers to cut and measure...
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Old 22-03-2011, 16:43   #11
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Re: Fiberglass Repair

**!! BE AWARE that the dryers in alkyd based paints (like Brightsides) are neutralized by the amines in the epoxy and they will not dry but will remains a gummy mess. Use a proper primer between epoxy and alkyd based paints!!!

good reason to stick to polyester as a first timer,no compatability issues,as long as glass is ground back enough,no reason why a good mechanical bond cannot be achieved using polyester resin,plus it is cheaper,easier ,faster to work with,and eliminates the need to respray with expensive polyeurathane paints.
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Old 22-03-2011, 17:07   #12
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Re: Fiberglass Repair

I've found that polyester makes a mediocre bond with cured glass. When We were building our Westsail decided to move a couple pieces of furniture that I'd bonded to the hull. I was able to rip the bulkheads off the hull with the tabbing pulling intact away from the hull but still bonded to the plywood. The hull was ground down and the area to be bonded thoroughly cleaned with acetone before the glass work. It was not a matter of residual mold wax, or poor prep. The polyester resin just didn't stick all that well to the older glass on the hull. Stuck real well to the plywood, however.

Polyester resin is easier to work with as you can vary the amount of catalyst to match the temperature so you can control how much working time you'll have. It also seems to be a little less finicky working with it and gives you more warning when it's time to step back and let the resin go off. Epoxy has to be mixed according to the mfg. specs. Working time is varied by the type of catalyst. Slow catalyst above about 75 degrees and quick catalyst below that temp. If you are working in temps much below 65 degrees, heat may be necessary to get it to cure suffciently quickly.

No matter what, you are going to have fill and/or grind the repair to get a smooth surface. You will have to coat the repaired surface with some kind of paint or gel coat to get a finished appearance.
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Old 22-03-2011, 17:14   #13
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Re: Fiberglass Repair

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Originally Posted by atoll View Post
...good reason to stick to polyester as a first timer,...,and eliminates the need to respray with expensive polyeurathane paints.
Plenty of good repairs have been done in polyester, sure, but I don't think this is even a real question anymore as regards real professional shops that do repairs of production glass boats - don't know of ANY that would still use polyester...

I've done plenty of epoxy/glass jobs, my own and others, and the "cheapest" method, an example done 20 years ago on an old dink, was just sanded and painted 3 coats with water-based floor & deck paint from Home Depot, no primer, and is still going strong (one new coat every five years, as usual for house paints). And all the jobs I've done in the high-end paint systems are all just fine as well.
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Old 22-03-2011, 17:35   #14
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Re: Fiberglass Repair

Quote:
Originally Posted by Whimsy View Post
Plenty of good repairs have been done in polyester, sure, but I don't think this is even a real question anymore as regards real professional shops that do repairs of production glass boats - don't know of ANY that would still use polyester...

I've done plenty of epoxy/glass jobs, my own and others, and the "cheapest" method, an example done 20 years ago on an old dink, was just sanded and painted 3 coats with water-based floor & deck paint from Home Depot, no primer, and is still going strong (one new coat every five years, as usual for house paints). And all the jobs I've done in the high-end paint systems are all just fine as well.
with a minor cosmetic repair like this one polyester is sufficient and hard to get it wrong,for a structural repair i would also use epoxy glass,fair,epoxy prime then respray with polyeurathane.

but the poster has allready stated he is a novice,may even be allergic to epoxy,and hasent a clue how the toe rail is fixed.
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Old 22-03-2011, 18:31   #15
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Re: Fiberglass Repair

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Originally Posted by atoll View Post
with a minor cosmetic repair like this one ...

I would hardly call 18" of broken and missing hull/deck joint at the widest part of the boat a "minor cosmetic repair".

Quote:
Originally Posted by atoll View Post
...the poster has allready stated he is a novice...
Quote:
Originally Posted by atoll View Post
and hasent a clue how the toe rail is fixed.
Even a novice, if indeed he is one, can apply himself to figure out how to remove and rebed a toerail, particularly with all this help at his fingertips - its not a space shuttle, itís a strip of aluminum, some nuts and bolts, and some sealant.

He seems willing enough to attack it, and I, for one, have confidence that he can do it well - the hardest part is usually just diving in and removing the first few bolts. Overcoming inertia and the discouragement of naysayers.

Quote:
Originally Posted by atoll View Post
...he...may even be allergic to epoxy...

My guess is that's about as likely as his winning the lottery and just buying a new boat outright.

But he should be warned - you think he canít do it.
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