: Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

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LittleCleo
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: Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by LittleCleo » Tue Jun 13, 2017 10:09 am

This past weekend I took the time to refinish my Souris river canoe. The underside of the ribs was experiencing a lot of wear, so I contacted the rental store where I bought the canoe. Their maintenance guy suggested putting strips of fiberglass veil on the underside of the ribs while doing the epoxy coat.
I kind of regret this decision since the veil left a very rough surface on the underside of the boat. I am going to sand it down and refinish it. This being a lightweight (41lb) portaging canoe I would prefer to keep the weight down.
Looking for advice here. Will sanding the bottom of the hull and coating with polyurethane give me a smooth fast finish, or do I need to apply another layer of epoxy?
PS for anyone curious the boat is 90% Kevlar but the outermost layer is fiberglass which is why you can sand the outside.
PICTURES:
https://imgur.com/gallery/RELBq

Thanks

Al



Jaysen
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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by Jaysen » Tue Jun 13, 2017 10:14 am

I think you need to use some fairing compound to fill the weave and smooth the hull. This will not be transparent though. You will want to finish it with paint. Between fairing, sanding, painting sanding, and painting (and sanding) you will be able to get the slicker than snot finish you want. Just takes time and patience.

LittleCleo
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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by LittleCleo » Tue Jun 13, 2017 10:21 am

Not looking to paint the canoe as I really like the color right now. It is smooth enough for my liking on the portions where there is no veil (really regretting putting those strips on). I'm sure if I resanded the entire canoe and recoated with epoxy it would smooth out. Just worried about all the weight that would add so I'm wondering if a polyurethane coat would do the trick.

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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by Jaysen » Tue Jun 13, 2017 10:28 am

Hard to tell from the photos, but I think you can add just a bit more to "fill the weave" then feather the edges to create smoother transition. If you don't use a fairing filler you will need to sand a bit more but I think a tad more epoxy and sanding will get it for you.

What did you use for those strips? biax tape? woven tape? What weight as well. i don't think you need to work to get it off, just fill and then the right amount of sanding for the type of tape you used.

LittleCleo
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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by LittleCleo » Tue Jun 13, 2017 10:38 am

This is the stuff I used:
http://www.noahsmarine.com/itemMatrix.a ... trixType=2

.5 OZ X 38" FIBERGLASS VEIL MAT that I cut into strips.
A very fine version of chopped strand mat.

My plan is to resand the entire of the bottom of the canoe (epoxy has cured so that is a necessary step regardless).

I may test a small area to see if polyurethane will smooth it out, but I'm guessing I will have to use epoxy

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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by Jaysen » Tue Jun 13, 2017 10:57 am

That stuff should go on light and smooth. Take a few close ups of the strips. My guess is that you just need a bit more epoxy and you will be happy. Hard to tell without a close up though.

LittleCleo
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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by LittleCleo » Tue Jun 13, 2017 11:29 am

I will get you a close up when I get home. You are probably right just needs more epoxy. But even in the areas where it is fully wet it still feels "rough". Hopefully sanding and another coat will get the job done

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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by TomW1 » Fri Jun 16, 2017 7:25 pm

That mat you bought says it is for gel coat repair not Kevlar or fiberglass or the use of epoxy. There are some mighty fine fiberglass patches and coatings out there that will work well for you. Check the store here under boat building supplies. If you have to adhere fiberglass to anything use epoxy.
Restored Mirror Dinghy, Bought OD18 built by CL, Westlawn School of Yacht Design courses.

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Re: : Epoxy VS Polyurethane for giving a Smooth Finish to Epoxied Fiberglass Veil

Post by bnaboatbuilder » Tue Jun 20, 2017 10:51 am

The patches used should be fine. They are fiberglass chopped strand mat so epoxy is appropriate.

My suggestion would have been to lay a full sheet of 2oz or 4oz woven fiberglass on the complete underside and wet out with epoxy and one or two additional weave-filling epoxy coats while a previous coat is still green. Using a full sheet won't create as much of an undulating bottom. As is, adding only the patches creates more thickness in a repeating pattern perpendicular to the water flow.

An oil poly or varnish will certainly make it very slick on the water.

- John

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