Fiberglass repair recommendation.

Rain Man

Super Anarchist
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Wet coast.
You can do it all in one go with polyester resin, if you don't go too fast. Grind in a taper on both sides of the hole, for a 2" hole in about 1/2" of glass the taper should end up about 6" in diameter (12:1). Get some mold release wax (borrow, don't buy, you won't need much) and coat a piece of smooth hard linoleum with the wax - you can get a piece at the local building materials recycling place if you don't have one. Place the lino wax-side up on the outside of the hole. Jam it in place with whatever works.

Start the layup from the inside by placing some wetted out 6 oz cloth down in the hole. The cloth will have to be a circle as big as the outer edge of the taper. You'll have to have some kind of instrument for poking it flat since the cloth will have to be pushed down through the hole. Smooth it out as best you can.

Then start placing more layers of thicker cloth on top, or just keep going with the 6 oz for a few more layers, whatever is easier. You can just place them on top of the existing layers and wet them out with a brush. Make sure they are fully wetted out. Monitor the temperature - stop if things appear to be getting too hot. You will probably need to stop every 30 minutes or so and have a coffee or a beer to let the laminate cook off.

Keep adding layers until you have filled up the hole and started on the inner taper. Pre-cut pieces of cloth will help here. When you have reached the top few layers start using a roller to get it smooth and get the bubbles out.

Let it cure, remove the lino, you will have a small amount of fairing to do around the edge of the taper on the outside. Epoxy + cotton fibres will do nicely. Sand to taste.

Done.

This method was used to fill in the hole where my saildrive used to be when I converted my boat to an outboard, and it was the first time I had done anything like this. It was easy. A half day's work at the most. Worst case? You grind it all out and start again.

dash

 

Memopad

Super Anarchist
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Marquette, MI
I would seriously be fine with an experienced person guiding and correcting me while I do all of the work. After doing it once, I'll be ok.
Ajax, I cut the deck off my boat, recored, reglassed, and repainted the thing with 0 prior experience armed with nothing but help from this forum. You can do it!

 

A guy in the Chesapeake

Super Anarchist
23,965
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Ok. Which one of you geniuses is going to come help me un-fuck it, when I start screwing it up and ask for help?
Gimme a day or two notice, and I'll be happy to swing by and fetch the tools you throw... You're in Edgewater, right? That's only about 1.5 hours from my office in Springfield.

 

Ajax

Super Anarchist
14,999
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Edgewater, MD
I would seriously be fine with an experienced person guiding and correcting me while I do all of the work. After doing it once, I'll be ok.

it should be fairly easy.. just think of it as a round hold that has a bend in the middle.. the question remains, are you going to take the whole thing out or replace what's there with new equipment..
Dread-

There is already a new, non-penetrating transducer installed nearby. This through-hull should be removed and filled.

Question:

Why are you guys recommending the use of polyester resin, instead of epoxy? I was in a recent discussion where I was told that -ester resins have a poor secondary bond to old fiberglass and resin, and that epoxy (such as West Systems) have a much stronger mechanical bond to previous fiberglass work.

Money is not really my issue here. I'm willing to pay for all the West Systems necessary to do the job right. All past attempts at cosmetic fiberglass work has resulted in total crap, especially where gravity was involved (working upside down). Which only brings out more questions:

What types of cloth? Some kind of bi-axial cloth, or just woven roving, alternated with CSM?

What weight of cloth?

Should the final exterior layer be CSM to avoid print-through, or will I be slathering on epoxy loaded with enough filler to hide the weave?

Am I supposed to paint this with barrier coat when I'm done, before I put on anti-foul?

I watched a Youtube video where a guy repaired a crash hole on a Laser. He used automotive Bondo to achieve the final fairing, but only because the boat is hauled from the water after each use. For the final fairing, do I just use one of the 400 series of West fillers? Which one is most appropriate for this job?

 

Memopad

Super Anarchist
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Marquette, MI
I'd definitely use epoxy.

I wouldn't use just roving or csm, you could get away with just using cloth (biaxial or otherwise). I don't know what the perfect material would be for this job but it isn't really a structural repair, maybe someone else will chime in here. The West System guides have a great bit about repairing a hole in a hull. You could follow that almost exactly and get good results. Only difference is you're working in a thicker area of the hull.

 

MW4506

New member
15
1
If you are intent on removing and closing the hole (versus leaving it and repairing the leak), then first find a good square piece of smooth thin plastic (like from a heavy-duty freezer bag, about an inch bigger than the hole, and tape it down tightly to the exterior of the hull. That will take care of what you experienced with previous gravity issues. Then patch from the inside using West System and cloth. If you are paranoid, over-do it on the inside with extra overlap at the inside surface level. It will be bullet proof with West System and cloth, and who cares what it looks like on the inside. After it cures, peel the plastic off the outside, It should already pretty much conform to the shape of the hull, and require only minimal light wet sanding. If that isn't perfect enough, a little lightweight microfiber fairing stuff mixed with a little more epoxy smeared over the area and re-sanding (like fairing a part of your keel) is all that would be needed. Having someone else fix this for you is like calling an electrician to change a light bulb. This is an easy fix.

 

BobBill

Super Anarchist
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SE Minnesota.
Ajax. I am beginning to get it. Epoxy is fine if not best...

Bondo on a Laser may do for a bit, but, considering any boat, even a Laser, supports a crew, keeping them or it from harm's way...always the prime consideration...safety...

I am imagining a simple through-hull opening, smooth...and I believe the West site and many others herein and elsewhere have simple methods to fill the spot.

I would consider the simplest relative to the hull thickness and the sandwich possible, including carbon patches inside and out, with layers and/or epoxy mix. In that I will defer to Vegas, Epoxymoron, Major Tom and Steve Clark, if they wish to contribute. Epoxymoron is associated with Epoxyworks and knows the product...

 
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BobBill

Super Anarchist
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101
SE Minnesota.
If you are intent on removing and closing the hole (versus leaving it and repairing the leak), then first find a good square piece of smooth thin plastic (like from a heavy-duty freezer bag, about an inch bigger than the hole, and tape it down tightly to the exterior of the hull. That will take care of what you experienced with previous gravity issues. Then patch from the inside using West System and cloth. If you are paranoid, over-do it on the inside with extra overlap at the inside surface level. It will be bullet proof with West System and cloth, and who cares what it looks like on the inside. After it cures, peel the plastic off the outside, It should already pretty much conform to the shape of the hull, and require only minimal light wet sanding. If that isn't perfect enough, a little lightweight microfiber fairing stuff mixed with a little more epoxy smeared over the area and re-sanding (like fairing a part of your keel) is all that would be needed. Having someone else fix this for you is like calling an electrician to change a light bulb. This is an easy fix.
Yes, Makes sense to me. +1.

 

Ajax

Super Anarchist
14,999
3,283
Edgewater, MD
If you are intent on removing and closing the hole (versus leaving it and repairing the leak), then first find a good square piece of smooth thin plastic (like from a heavy-duty freezer bag, about an inch bigger than the hole, and tape it down tightly to the exterior of the hull. That will take care of what you experienced with previous gravity issues. Then patch from the inside using West System and cloth. If you are paranoid, over-do it on the inside with extra overlap at the inside surface level. It will be bullet proof with West System and cloth, and who cares what it looks like on the inside. After it cures, peel the plastic off the outside, It should already pretty much conform to the shape of the hull, and require only minimal light wet sanding. If that isn't perfect enough, a little lightweight microfiber fairing stuff mixed with a little more epoxy smeared over the area and re-sanding (like fairing a part of your keel) is all that would be needed. Having someone else fix this for you is like calling an electrician to change a light bulb. This is an easy fix.
Your plan is the one I like the best, as it allows me to work inside the hull, where my mess will be hidden. I want to do the least amount of work on the outside of the hull, because my cosmetics skills are absolute crap.

The interior of the original hull, shows a very large weave cloth. I have no idea what is in the intermediate layers. I need solid recommendations on what kind of cloth to use. I barely even understand what "biaxial", woven roving and CSM means.

 

Innocent Bystander

Super Anarchist
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Lower Southern MD
If you are intent on removing and closing the hole (versus leaving it and repairing the leak), then first find a good square piece of smooth thin plastic (like from a heavy-duty freezer bag, about an inch bigger than the hole, and tape it down tightly to the exterior of the hull. That will take care of what you experienced with previous gravity issues. Then patch from the inside using West System and cloth. If you are paranoid, over-do it on the inside with extra overlap at the inside surface level. It will be bullet proof with West System and cloth, and who cares what it looks like on the inside. After it cures, peel the plastic off the outside, It should already pretty much conform to the shape of the hull, and require only minimal light wet sanding. If that isn't perfect enough, a little lightweight microfiber fairing stuff mixed with a little more epoxy smeared over the area and re-sanding (like fairing a part of your keel) is all that would be needed. Having someone else fix this for you is like calling an electrician to change a light bulb. This is an easy fix.
Your plan is the one I like the best, as it allows me to work inside the hull, where my mess will be hidden. I want to do the least amount of work on the outside of the hull, because my cosmetics skills are absolute crap.

The interior of the original hull, shows a very large weave cloth. I have no idea what is in the intermediate layers. I need solid recommendations on what kind of cloth to use. I barely even understand what "biaxial", woven roving and CSM means.
A DA Sander with coarse paper will turn a minor "mess" on the outside of the hull fair pretty quickly. Finish with a low density filler and sand with a mid sized long board. I like 3M Vinlyester marine filler for final fairing as it cures quickly (just like polyester) and sands pretty easily. I used some over a cradle ding on a lead keel 12 years ago and it is still sound and the repair is invisible under bottom paint.

Essentially, all the recommendations you are getting say the same thing. Grind to clean glass with an adequate chamfer. Use coarse paper/wheel to leave an aggressive tooth. Use a backer with mold release or wax. Build up multiple layers of CSM and cloth in sizes that follow the taper.

I prefer to chamfer both sides and start on one side until a green cure of the lowest layer then remove the backer and do the other side so that the repair "clamps" the hole from both sides. The green cure gives you a solid surface to bond to but the new epoxy will cross link to and bond thoroughly to the green cure material.

If you do this during a spring haul out, it's about 2 days at 1-2 hours/day tops using epoxy. You can grind and lay the patch day one. Fair/fill/fair day 2. Final fair and paint later on day 2 or day 3. You can do it all in one day using polyester but I'm really a fan of epoxy for secondary bonds. Sand, prep, mask and paint the bottom while the epoxy is curing.

 

Ajax

Super Anarchist
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Edgewater, MD
What is a green cure? Kicked, but not totally solid?

I understand to alternate CSM with cloth. In absence of recommendations, I guess I'll go with a heavy weight cloth.

Should the final, exterior layer of fabric be CSM to avoid the weave showing through, or does it not matter because I'll be applying filler and fairing material?

 

Slick470

Super Anarchist
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323
Virginia
I'll add, do not use automotive bondo for this. It will absorb water and swell and cause your fairing job to fail unless you can seal it completely. On a car this is possible, on a boat, below the waterline, I wouldn't chance it.

It is however great for fairing damaged wood trim in your house. (or plugging up a old kitty door hole in a solid wood door that you want to keep because it matches the rest of the 60 yo doors in your house)

 

Grande Mastere Dreade

Snag's spellchecker
ok, I'm seeing a lot of advice to repair the hole from the inside... this is not what I've read here before and not what west system recommends... hole repairs / patches are to be fixed from the outside of the hull I sure as hell wouldn't want a patch on the V of my bow on the inside especially if that's a point that might make contact with something in the water, nothing like having your plug knocked out inadvertently... I would want the force of the water pushing the patch against the hull, not away from it..

chapter 4.3 in the west system guide is where you need to start if you have not read it already ajax..

http://www.westsystem.com/ss/assets/HowTo-Publications/Fiberglass-Boat-Repair-and-Maintenance.pdf

the rest of the guides..

http://www.westsystem.com/ss/use-guides/

give west systems a call, 866-937-8797 , they'll help you with everything..

 
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MW4506

New member
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1
If you pour a thin amount of epoxy into the hole from the inside before you stick any cloth in, that layer will become your exterior face, and you won't have any cloth fibers to contend with if you have to do any sanding.

 

BobBill

Super Anarchist
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101
SE Minnesota.
Never Bondo...and, a question, is CSM, chopped mat, nec? Why not layered glass, with successive layers added to tacky layer (green) and so on, and finish cover of peelply etc. (I see replies in progress as I type...) not so sure my idea of hole to be filled is same as actual...but the idea is resonant.

 
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Ajax

Super Anarchist
14,999
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Edgewater, MD
Bob-

Yes, CSM is chopped mat. I've read that the typical 4kt shitbox hull is constructed of alternate layers of woven roving and CSM with the final layer being CSM to avoid the weave showing through the gelcoat.

This may not be a problem for me, if I use enough filler, paint the spot with barrier coat and anti-fouling. I dunno. Not getting any solid answers on that question.

Ok, repairing from the inside may not be wise, as the patch could blow into the boat. Plus, I have a structural member inside the boat, adjacent to the hole, that precludes grinding a 12:1 bevel, 360 degrees around the hole. This means that I probably MUST do the repair from outside.

The glass could be nearly an inch thick at the apex of the V, meaning I'll need to grind a one foot friggin circle into my hull.

 

Memopad

Super Anarchist
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Marquette, MI
Biaxial glass just has fibers running in multiple directions. You can get it in 45 degree and 90 degree variations usually. Again, not important for this repair. You can use a unidirectional cloth here, just turn it 90 degrees for each layer you add if you want the "bi" directional weave ;) I would probably hit this from the out side not inside. You're going to be fairing the outside no matter what you do, so just go from the outside.

 




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