Help with hull cracks

[Boatman53]

I've got a question for these esteemed members here. I'm a wood guy and when I'm faced with fiberglass work I pass it along to a buddy of mine. But this is different. I've got three Mad River Malecite canoes in the shop at the moment and I'm making a bunch of gunnels for all three boats. Two of the boats are paying customers and they are getting mahogany rails. The hulls are fine just needed a bit of compound and wax and they look great. The problem child is my boat. It was given to me about four years ago 'cause the owner didn't want to have me fix it, they just bought a new boat. The hull is badly sun damaged and didn't buff out so I decided to sand and paint it. It's a Kevlar hull and the gel coat has some fractures in it that I know will telegraph through the paint. So here is my question what is the best to seal up these fractures, or do have to sand through them. I don't think that is the best option. Would crazy glue run in the crack and fill it? I'll be painting it green again and will have cherry rails, decks and seats. Here are the photos.

Jim

 

[sailsman63]

You might find part of this thread interesting, start around post #9.

​The user there, Mike McCrea notes that this is the "wrong way" to fix gel coat, but it seems effective.

Don't try to sand through. Once you have sanded through the gel coat, you are immediately into the various fibers, glass or Kevlar, that make up the structure of the boat.

I'd be concerned about the long-term stability of super-glue. Marine epoxy is rather easy to handle, especially when working with smaller batches. If you can handle thinning varnish or blending a couple of stain tints, you can handle marine epoxy.

Question: have you started sanding yet, or is the surface haze still just the sun damage?

 

[Boatman53]

Thanks for the input. The photos are are just after we washed it off, no sanding yet. I use West System epoxy all the time for only about thirty years but felt it might be too viscous. Never really tried thinning it, this might be the time.
I'll check out the link you noted now.
Jim

 

[scoutergriz]

I'd second the west system, But first I'd take a dental pick and probe the larger cracks looking for de-lamination. If there is, you'll need to remove any loose bits. At that point you might need some tinted gel coat. When done give it a good rubdown with rubbing compound on a soft wheel.
Going by the last picture you've got some serious oxidation, but because it scratched green, you still have some solid stuff to work with, a second buffing with polishing compound and a final paste wax will have it looking real good

 

[Guest]

. I use West System epoxy all the time for only about thirty years but felt it might be too viscous. Never really tried thinning it, this might be the time.

If you opt for the epoxy fill cheat method it will help to have the resin as least viscous as possible. I have never thinned epoxy, perhaps someone can address that possibility.

I know that there are less viscous epoxies (or hardeners) available, but my epoxy supply has never gotten more involved than West 105/206 (or 205) and G/flex.

I just make sure that the 105/206 (slow hardener) is warm before mixing and that the boat is positioned with the cracked area as near to horizontal as possible. Unless the cracks are fortuitously all on the same level plane that means doing them one at a time.

Box out a small area around a crack with tape to catch the drips, paint on the epoxy and let it seep in and harden. You may need to repeat that procedure on the same crack, either while the 1[SUP]st[/SUP] coat is still green or after sanding and blush removal.

There are a couple of advantages to gel coat repairs. Using like materials for starters; if you do an epoxy repair you will not want to do gel coat re-repairs in that area. You can find gel coat repair kits in very small quantities. And you can TRY to color match the gel repair to the hull, although with that sun faded hull that is unlikely, and you plan to repaint it anyway.

Is it worth buying a specialty un-viscous epoxy just for those repairs if you have regular West System on hand?

As Scoutergriz suggests remove any loose chips or flakes whatever you do.

 

[Boatman53]

West System it will be. A little research on line and I now remember why I never thinned epoxy. I'll use heat instead, that should be no problem with the weather we have been having. I'll start on those tomorrow.
Here is a shot milling two canoes worth of scuppers on the inwales.

Jim

 

[Jim Dodd]

Good advise so far !

Jim

 

[Will Derness]

Wouldn't a gel coat repair be the best approach?

Some time ago I had a sea kayak that had a quarter size chip in the gel coat, deep enough the fabric below was exposed.

A gel coat patch kit from Current Designs, with matching pigment did an excellent job of filling it and with a extremely fine wet sand you can't tell there was ever a void there.

My instincts would be to use a gel coat patch, regardless of tinting issues. It should bond well to what needs bonding and you'll have a consistent hull material to work with in finishing. If it doesn't hold, epoxy could be a fall back option.

 

[Guest]

Wouldn't a gel coat repair be the best approach?

My instincts would be to use a gel coat patch, regardless of tinting issues. It should bond well to what needs bonding and you'll have a consistent hull material to work with in finishing. If it doesn't hold, epoxy could be a fall back option.

All true, and the cracked areas are small and distinct, unlike the massively spider cracked dumpster-ready hull bottoms I typically try to resurrect.

But I am scairt of gel coat. I’ve never done it. Hell, I’ve never even seen it done. My limited understanding of gel coat repairs is that there are different kinds of gel coat that require different application techniques and curing, and that the hardener agent needs to be relatively fresh.

I have heard enough ooops I effed it up stories of gel coat repairs to be leery of trying it without someone experienced lending a guiding hand.

 

[Boatman53]

If the hull itself wasn't so sun bleached I might be swayed to try the gel coat but as I said in the start I refer all my F/G work mostly gel coat to my friend. I also have a Kevlar ADK guide boat built by Hornbeck that has some similar features and I asked him about repairing those 'cause overall the hull looks good. He refused to do it, said it wouldn't hold up or something. Anyway the canoe is in need of paint so it shouldn't matter what I use as long as it gets in deep and holds.
Jim

 

[Will Derness]

Well this repair does provide you with an opportunity to work with gel coat with little downside risk. Its an old hull, if it doesn't hold up you can epoxy it later.

No one wants to do work twice, but if Mad River sells gel coat patch kits I would be be strongely pulled in the direction of giving that a shot and gain some experience on the journey.

 

[Jim Dodd]

Gel coat question.

Is it polyester based ?

If so, I'd go with epoxy for it's superior bonding.

I too have not used gel coat.

Jim

 

[Boatman53]

Yes gel coat is polyester based. It really is a skill I don't think I want. I have a gallon of epoxy so I don't "need" to buy anything. Unless it was proven better.
Jim

 

[Guest]

I expect the epoxy method will work fine for you. You may need a 2[SUP]nd[/SUP] coat atop the cracks to bring them completely flush.

I have a freebie (rotted wood gunwales) glass Independence that I rebuilt 20 years ago. The chines were a mass of spider cracks stretching for a five foot area on both sides. I sanded and epoxy filled that expanse of cracks Not my best work, I was still learning, but the epoxy covered cracks are as sound today as they were when I first covered them.

What is the painting plan? Wet sand the entire bottom, prime and paint….with what?

 

[Boatman53]

So far it is sanded with 220 and followed by scotchbrite. Once the cracks are delt with I'll hit it with 320 wet/dry and paint. No primer. I know I have some Interlux green paint in the shop, it is a standard color on the little Beetle Cats I take care of.
Didn't get to starting on those cracks like I thought. I coated the back faces of the new rails with epoxy today and was sure I would have some extra to play with but it took all I mixed to do the rails. Tomorrow is another day.
Jim

 

[pblanc]

There are lots of options if you plan to paint the hull. Cheapest is probably using a polyester auto body putty to fill in the cracks and chips. Evercoat makes gel coat repair kits for boats that are pretty easy to use. You need to cover the putty with waxed paper while it cures. I have also used high-build marine enamel primers also. The one I used, Z Spar Hi-Hide, has been discontinued but there are probably others.

Since you already have epoxy, your plan seems like a reasonable approach but your results will be improved by adding a fairing compound to the epoxy. I have used West Systems 410 Microlight additive with good results, however 407 micro-balloons might be a better choice if you plan to paint the hull with a dark color. The fairing compound will allow the epoxy to fill gaps better and is easily sanded when cured. Here is a table of fillers sold by West Systems: http://www.westsystem.com/ss/filler-selection-guide/

This pdf from West has more information than you ever want to know about filling, fairing, and finishing:

http://www.westsystem.com/ss/assets/...-Finishing.pdf

 

[Guest]

. No primer. I know I have some Interlux green paint in the shop, it is a standard color on the little Beetle Cats I take care of.

Interlux is great marine paint, as I’m sure you know. I had to look up Beetle Cats. Cool stuff.

http://www.beetlecat.com/store/scripts/default.asp

Please post some repair and repaint results.

 

[ezDuzit]

As long as you intend to paint, then WEST epoxy is best (remains flexible, compared to polyester), as long as you don't need to later adhere gelcoat to it (not so good). Never thin it!

But those cracks sound like they are structural failures. Plain epoxy isn't going to help with that--you need fiber reinforcement, if that is the case.

Any paint system is also going to add weight, in case that is important.

 

[Boatman53]

Thanks for everyone's input so far. There is no evidence of structural failure, I think it was just rough handling. I have a plethora of West System fillers and I'm not afraid to use them.
So here is what I did today. First I worked on the boat for the paying customer, and got the inwales fitted.

Then I got after those gel coat fractures.

That's where I ended today. Tomorrow they get epoxy. Then more sanding and filling. I know the paint will add some weight but that will be the price paid for a nicer looking canoe.
Jim

 

[Boatman53]

So here is the epoxy work. Using an artist palette knife I worked the epoxy into the opened up areas and the put tape over everything. The tape keeps the epoxy from running off and can even force it into the cracks some.

Tomorrow the results.
Jim