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Thread: exposed fiberglass weave prior to varnishing?

  1. #1
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    Default exposed fiberglass weave prior to varnishing?

    Hello, I'm building a cedar strip kayak and am currently doing the final sanding before varnishing. I am using 80-120 grit sandpaper on a ros. In a few spots, the glass underneath is faintly visible; I've attached some pictures. It doesn't feel like I've hit the glass and it is smooth but the weave is visible in several places. Should I skim coat with epoxy and sand again or will varnishing hide this? I skim coated a few places where this occurred and sanded it after it had cured. I ended up exposing the weave again trying to get the surface to match the rest of the dullness of the sanded epoxy with my ros. So if I do skim coat it, the coats should be somewhat thick? or could I just lightly wetsand the lightly skimmed surface by hand to try and get rid of the shiny surfaces?







    Also, is it better to use a sanding block when wet sanding or just use your hand?

  2. #2
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    Default Re: exposed fiberglass weave prior to varnishing?

    I'll find out in a few minutes. I am clear coating with automotive paint right now. Second coat to go. I probably won't know really until I get the boat out in the sun. Right now with one wet coat I don't see any of this.

    Same thing - a kayak with 6oz cloth in west system.

  3. #3
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    Default Re: exposed fiberglass weave prior to varnishing?

    You can wipe the spots down with water to get a temporary look at how much they will or will not show up when varnished. Usually, spots like this, where you've sanded down into the glass slightly, aren't a big deal and will pretty much disappear when varnished. Sometimes they'll show up as patches of tiny silver sparkles when bright sunlight hits them at just the right angle, but will otherwise usually look fine. Adding resin over the top of them isn't likely to make them disappear any more than just varnishing them will, so it's probably not worth fooling with. Don't sweat it.

  4. #4
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    Default Re: exposed fiberglass weave prior to varnishing?

    Lagomorph,

    My second coat of clearcoat has dried and there is no evidence of this kind of weave. Everything else I did poorly showed up including some things I never noticed. I might never clear coat again. But my skills are minimal.
    Good luck

  5. #5
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    Default Re: exposed fiberglass weave prior to varnishing?

    It will disappear if you just touched the weave and may mostly disappear if you didn't fully wet-out the glass. Either way, not much you can do except try the varnish and if not happy, light sand and paint.

  6. #6
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    Default Re: exposed fiberglass weave prior to varnishing?

    Thanks for the replies folks. It mostly disappears when wiped down with a wet rag. All the glass was fully wet out originally so all this is just from sanding. Looks like i'll be alright just varnishing.

    upchurchmr:
    Did you clear coat over varnish or did you clear coat directly over the epoxy/fiberglass?

    edit:
    Also, I just came across this article about placing polyester film over a wet out surface to achieve a flat finish with minimal sanding: http://duckworksmagazine.com/03/r/ar...ass/bottom.htm
    Anyone here ever try that before?
    Last edited by Lagomorph; 01-29-2012 at 07:06 PM.

  7. #7
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    Default Re: exposed fiberglass weave prior to varnishing?

    Lagomorph,

    I followed other peoples suggestion and applied the clear coat directly to the epoxy. I don't know what else you could do, since primer, etc would cover the wood look. The salesman at the paint store really did not want to sell me the clearcoat since he did not know what might happen without the typical process.

    The clearcoat was much easier to get an even coating than varnish. Some of my application was spotty in places so I will be doing a couple more coats. Wouldn't have been necessary if I was any good.
    Reading the line above looks like I contradicted myself. The spraying operation seemed very easy, used the material directly out of the can, no cutting, etc. I'll probably forget the can of varnish I still have.

  8. #8
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    Default Re: exposed fiberglass weave prior to varnishing?

    Is your clear coat UV resistant? If not than you will still have to apply spar varnish. The epoxy will turn milky white over time if it is not coated with the correct product.

  9. #9
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    Default Re: exposed fiberglass weave prior to varnishing?

    Frank R

    The great thing about the Automotive Clear Coat is that is the only thing providing UV protection on a car. So it should be good enough, especially since my cars sit out in the weather all their life. Possibly I should have gone with the $400/ gal stuff not the $100/ gal, but this Kayak should not sit out every day.
    I guess I can report accurately in a couple of years. My son's 10 year old Car needs a touch up of the clear coat - not sure I am brave enough to try.

  10. #10
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    Default Re: exposed fiberglass weave prior to varnishing?

    I paint cars for a living, the $100 a gallon should work just as well as the more expensive type. Usually the more expensive ones are a higher solids and need a little reducing. Two or three coats unthinned will be fine. If you want a real shine you can sand with 1500 grit and buff. Be warned when sanding and buffing you risk cutting through any high spots. If your epoxy work isn't blocked out complety flat don't sand and buff.

  11. #11
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    Default Re: exposed fiberglass weave prior to varnishing?

    Hunky,

    Thanks for the comment, I was going on trust. Unfortunately my prep work isn't good enough to spend too much time. The epoxy work is pretty good, but I'm about done. 4 months over my promise date.

  12. #12
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    Default Re: exposed fiberglass weave prior to varnishing?

    In reference to the original question, this old photo is of the first strip kayak I ever built, back about 1973 or '74. Unlike many these days, there was no internal sheer piece and the hull and deck were simply joined with both inside and outside, double-layered, fiberglass-taped seams. Those on the outside were then filled with resin filler coats and sanded smooth, tapering down the edges of the seam tape and yielding a continuous surface. This exposed a fair amount of sanded, feathered-out glass tape weave along the edges of the tape strips, similar to the spots your photos show. For all practical purposes, when varnished, the weave disappeared and the seam was basically invisible.


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    Default Re: exposed fiberglass weave prior to varnishing?

    I am at the same spot right now. I noticed a bit of fiberglass weave showing through my sanding as-well. This post made me feel better about it. However, there is a spot on my deck where i sanded through the epoxy (no fiberglass) straight to bare wood. Is this going to be noticeable after varnish? IMG_2409.jpg

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    Default Re: exposed fiberglass weave prior to varnishing?

    Epoxy makes wood turn a different color than varnish usually, so that is something to consider.
    Did this area have no glass or did it all get sanded out?

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    Default Re: exposed fiberglass weave prior to varnishing?

    In addition to potential color variations, you may even get texture variation in time, as the epoxy areas will behave differently from the varnished wood areas when exposed to moisture, UV and time. It takes a certain amount of resin coating thickness to achieve the sealing power that we are usually looking for when epoxy coating something. Gougeon generally suggests two thin-ish rolled-on coats (about ten mils total) on surfaces which will not get sanded, and three coats on surfaces which you intend to sand smooth (figuring that about one coat's worth will get sanded off during the smoothing process). If you are all the way down to bare wood in spots, then you obviously have some areas which are no longer epoxy sealed, mixed with areas which are, and that's asking for trouble down the road. Unlike a few patches of visible glass weave patterns, this one can be pretty serious and more resin coating and smoothing is in order to repair it.

  16. #16
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    Default Re: exposed fiberglass weave prior to varnishing?

    No fiberglass. epoxy on bare wood. I know that some people just varnish straight to bare wood for the trim. I did the epoxy as an extra safety step. Just wondering is this spot is going to be an eye sore.

  17. #17
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    Default Re: exposed fiberglass weave prior to varnishing?

    Yes, IMHO

  18. #18
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    Default Re: exposed fiberglass weave prior to varnishing?

    Quote Originally Posted by Littleta621 View Post
    No fiberglass. epoxy on bare wood. I know that some people just varnish straight to bare wood for the trim. I did the epoxy as an extra safety step. Just wondering is this spot is going to be an eye sore.
    Depends on your tolerance for imperfection.
    It'll be different to the surrounding areas, but i'd live with it. Build it up with epoxy layers so it is a similar thickness to the area around it. That'll minimise the difference i think. Uniform coatings of varnish and she'll probably be very discrete.
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