More fiberglassing questions and issues

I recoated my boat last night and it turned out ok, but I had a couple issues.

  1. Air bubbles in the resin. I know this comes from over working the resin, but I tried not to work it more than I had to. I mixed it in a cup, poured it on the hull, spread with a spreader, then rolled with a west systems foam roller. I saw the air bubbles as I was rolling and followed WS’s book’s advice of using a hair dryer on cool to try to blow the bubbles out, but it didnt work. They’re not terrible, but still noticeable. What can I do better?

  2. The Kevlar on the bottom was more exposed than I initially realized, and became fuzzy/rough when the resin cured. Its not terrible, but it certianly isnt smooth over 20%+ of the bottom. I know if I sand it it will fuzz more… what’s the best remedy to this? light sanding and more resin? or should I just go to a couple coats of Varnish?

  3. I cleaned the hull with lacquer thinner before I began, but apparently not well enough. In a couple areas I got fish eye and ‘waterfall’ due to the resin being repelled (not a curtian/sag due to too much resin). Now I have some small areas that aren’t the prettiest. They’re all above the water line so its just cosmetic, but I love my boat and want it to be pretty. Can I re-clean those areas, sand, and glass/varnish over them?

  4. How do Pros get the glass like finish?!?! I hate resin!

    Overall, the fiberglass patches turned out very well. I had about 10’ of cuts on the bottom from the previous owner that I patched over with fiberglass tape. That part actually went very well. You can only tell they’re there if you look very closely, so Im happy about that. The issues arose when I recoated the entire boat.

I think the bubbles
may be a result of rolling too fast. You need to roll smoothly and slowly. You also need to use the very thinnest roller available (1/8" I think).

You can avoid all that by forgetting about the roller and simply spreading with a plastic spreader. There is no need for a roller.


– Last Updated: May-29-14 10:00 AM EST –

A foam roller is an OK way to apply epoxy. I don't do it that way but a lot of pros do when they need to cover a large surface. But your roller will leave a textured surface, if not bubbles, and you need to tip it out with a brush. A disposable foam brush works fine and ideally you could possibly arrange to have someone follow behind you and your roller and tip it out as you go. I apply epoxy pretty much as I would varnish. This video might be of some help.

As for the aramid fibers, if they are impregnated with epoxy and raised above the surface you might actually be able to shave some of them off with a sharp knife like an Exacto knife. I would try that and then wet sand to remove any residual. If you have a coat of epoxy on the aramid and don't get too vigorous with your wet sanding, you will be sanding epoxy, not aramid, except for the raised fibers.

Any area of the hull that did not take the epoxy well I would wet sand down. If you are patient and careful, I have found it is pretty easy to tell when you are starting to abrade the aramid fibers and at that point you stop. I would clean the hull well using first soap and water, then acetone, then denatured alcohol (I don't have any data to support this sequence but it is what I do and it seems to work) and then recoat with epoxy.

Any areas of cured epoxy to which you are adding more epoxy should be washed with dilute soapy water (I use Dawn dish washing detergent) then rinsed well and gone over with alcohol before applying any more epoxy. This is done to remove any potential amine blush which can interfere with epoxy bonding.

Excellent video
Best tutorial on varnishing I’ve seen. Did you apply that varnish straight, or do you thin any of the coats?


– Last Updated: May-29-14 10:50 AM EST –

Alrighty...Looks like I have more sanding in my future =/

Ill give everything a good sanding, a thorough cleaning, and another coat of resin.

I dont know if I should varnish it after the issues are fixed. I see boats with flaking varnish and it looks like hell. Is that just a result of poor preparation? or does it inevitably end up flaking over time?

UV protection
The purpose of the varnish is to protect the epoxy from UV degradation. It takes a good bit of continuous UV exposure before epoxy begins to become chalky, crack, and start to flake off, but when it goes is can go pretty quickly.

It too looks like hell and is harder to fix than checkered varnish.

Varnish does not last forever but it lasts a good long while, at least several years for most folks. Virtually all stitch and glue or strip built canoes and kayaks that are not painted are varnished.

The thing about varnish is not to wait too long before refreshing it. Revarnishing is a bit of a chore requiring some preliminary sanding, multiple coats, and wet sanding between coats (if you want a really nice result) so sometimes people put it off too long. If the varnish has not deteriorated much, a preliminary light sanding and cleaning is all that is required. Once the varnish becomes excessively checkered there is usually no recourse but to sand it all off.

Once you have your hull epoxied and smoothed to your satisfaction, wet sand it with waterproof paper of around 330 grit or so and clean it well to prepare it for the varnish. I would suggest three coats but you might get by with two.

I got the glass like finish by sanding
after the last coat. But if I understand what you did, there were several differences in what I was trying to do.

I had removed residual Kevlar fibers by torching and scraping. Then I sanded things reasonably smooth. And then, on a hot day in the carport, I rolled on about five successive layers of West 195/205, using the method of rolling the next layer after the previous one was just hard enough, but had not had amine blush rise too much to prevent adhesion.

Yes, the surface was orange-peeled after the fifth layer, but perhaps because it was a hot day, any bubbles had popped. Maybe I tipped them off, I don’t remember.

The final orange peel disappeared with random orbit sanding.

One reason I would not recommend this approach is that the coating is just a bit brittle. A high tech varnish might have been better. But there it is.

what grade sandpaper for orange peel?

– Last Updated: May-29-14 12:15 PM EST –

You had to be pretty careful to use an orbit sander to even out orange peel, didn't you? What grit did you use? Or were you using something like rubbing compound?

Be careful - sanding dust
Be careful as you’re sanding down the newly coated areas. Sanding dust of any sort is bad for you but I’ve always heard that epoxy that wasn’t fully cured (just because it’s hard doesn’t mean it’s cured) is some really nasty stuff. I sprung for a $30 respirator and it’s some of the best money I ever spent. Much more effective than a mask.


I painted
I painted in the past and always wear a nice dust mask or respirator. I always wonder how people can work in that and not have their lungs literally hurt the next day…

Only normally careful. I don’t remember
the grit, but it was upwards of 120. With a random orbit sander, one doesn’t need to use super fine grit, just a light, quick approach.

The other thing is to make sure any amine blush is cleaned off the surface. Otherwise it fouls the paper.

One wants to wait until the epoxy IS
fully cured. Otherwise the sandpaper may load up. And amine blush must be removed from the surface too.

I used to be quite epoxy sensitive, but I have not had problems with West epoxy, neither with the fumes nor with the dust. I wear a simple “paper” mask. Another thing is that my random orbit sander doesn’t raise much dust, and vacuums up some of the dust on its own.