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Thread: Refinish Cedar Strip Canoe

  1. #1
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    Oct 2006
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    Default Refinish Cedar Strip Canoe

    Hey, y'all. So I have a glassed over cedar strip canoe I recently bought. The varnish/urethane needs to be replaced. I sanded it down then discovered it's best to maybe use a heat gun?? Anyway, all the varnish is not sanded off, it's a little spotty. Can I, should I use a heat gun to try to remove the rest of the coating?

  2. #2
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    Default Re: Refinish Cedar Strip Canoe

    I would not use a heat gun. The canoe is probably glassed with epoxy which will soften under heat. I would hit the spotty spots with sandpaper but take care not to start abrading the fiberglass.

  3. #3
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    Default Re: Refinish Cedar Strip Canoe

    If the underlying glass was not laid on with several over-coats, you may not get all of the old finish off. This is OK.
    Don't go near the epoxy-glass with a heat gun or chemical strippers.

  4. #4
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    Default Re: Refinish Cedar Strip Canoe

    As Bill says, I would NOT use a heat gun unless you intend to remove the fiberglass or otherwise damage it. If the spar varnish over the glass is "blotchy" you want to remove it because when you over-coat with a new layer of varnish, you don't want to see that through the new layer of varnish.

    If you sand down to the epoxy - removing all the spar varnish, I'd recommend another coat of epoxy, a wet-sand after about a week of cure time, and then more spar varnish. Depending on what particular brand of epoxy that you use, you'll want to pay attention to the manufacturer's instructions on what surface prep procedures you should follow to get a good bond between the epoxy and varnish and a proper cure.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  5. #5
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    Default Re: Refinish Cedar Strip Canoe

    As mentioned, do not use a heat gun - and it doesn't matter whether it's epoxy resin or an old polyester resin fiberglassing job. Heat is bad for either one and only used to remove them (destroying the resin in the process and not likely something you want, or need, to get into if the boat is in decent shape). Other than maybe filling a few old scratches if you have any, or making any needed spot-repairs, I can't see any reason to apply any new epoxy. The resin filler coats under the varnish are quite a bit harder than the varnish and it's not a big deal to sand off the varnish and give it a couple new coats of a good UV-filtered marine varnish to protect the fiberglass and resin from sun damage (which is critical to the life of the boat).

    Unless you're using a very powerful sander (like a big disk) it's very unlikely that you will sand deeply enough into the resin filler coats or fiberglass to do any serious damage in the process of just removing old varnish. Just take it easy, either by hand, or with a good high-speed orbital or random orbit sander (100 grit or so). You can usually test for blotchy spots by going over the surface with a wet sponge. While it's wet, the surface will have a similar color and look to what it will eventually get with a new coat of varnish. If you've sanded evenly and you're pretty sure the varnish is gone and you still see discolored or milky areas when you wet it down, then you may have some spots where the fiberglass has some UV damage. This isn't all that rare on strippers where the varnish has been neglected, which unfortunately is one of the quickest ways to ruin one.

    In the mean time though, I'd continue careful sanding and giving it the wet sponge test to see how It's coming along. You'll know soon enough if it's not going to do the job and is going to need more substantial repair.

  6. #6
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    Default Re: Refinish Cedar Strip Canoe

    I always find that when I strip all the varnish off a boat, invariably there are some spots - usually at the stem reinforcement strip where it is blended out - where I see that a little of the glass fiber has been exposed. Also, when I glass boats, I only apply one more coat of epoxy after I've buried the weave to keep the weight down. (Actually, on the interior, I usually only apply a single coat of epoxy to the glass on the small boats that use 4oz loth because I want the texture to keep from slipping around.) That's why I generally figure that it's not bad practice to add epoxy.

    One of my friends who has a sea kayak we built together stripped his varnish and we noticed that he had some areas in the field of his boat at the turn of the bilge and the crown of the deck where the sanding had removed more epoxy than we would have liked. A simple coat of epoxy doesn't hurt much other than weight. Still as Todd mentions, it depends on how much resin was originally applied to the boat - it may not be necessary if you've buried the weave quite a bit.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  7. #7
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    Default Re: Refinish Cedar Strip Canoe

    Okay. Thanks for the help. I won't use a heat gun. Here is the detailed version of what happened... I picked this canoe up, in disrepair, and need to refinish the varnish. I sanded it down and had the blotchy spots like I mentioned. I did the wet wipe and I even spar urethaned a test spot. I was able to accept the light blotchy spots with what I saw because I didn't want to spend the hours necessary to get it all even. I haven't urethaned the whole thing yet, but transported the canoe on top of my car, in the rain. When the canoe was completely wet down with water the blotchy spots popped out pretty bad and also around the perimeter of the blotchy spots I could see white scratch-like areas that made them pop even more. I'm afraid if I go ahead and urethane the canoe as is, that my initial assessment of my test spot will be poor and that all these imperfections will show through. The blotchy spots are a kind of light greenish-yellow. Maybe now that I haven't been sanding for a while I can give it another go with some sandpaper and see if they start to clear up. I've only worked on the exterior of the canoe so far... How the heck is the best way to remove the chipped and faded finish from the inside, which is glassed as well. I guess this also leads me to the question of what is the best way to maintain this finish without having to go through all this again. I know I should keep it out of the sun, dry it off when I'm done, the basics. But should it be waxed? recoated every couple years? ...?

    1) Do you think the blotchy spots will pop as bad when I urethane it, or will the urethane even it out?
    2) What is the best way to refinish the interior with its concave curvature?
    3) How do I maintain the finish once its on?

    Thanks so much for help everyone. You're saving me hours of time and a huge headache.

  8. #8
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    Default Re: Refinish Cedar Strip Canoe

    Be careful. The white "scratch-like areas" may be glass starting to be exposed - do you see a weave pattern? Pictures would be a great help here.

    The blotchy spots will likely be just as bad when covered. It sounds like they are residual varnish or urethane from the previous coat.

    As far as the finish that you put on, you want a varnish or urethane with UV filters in it. Some are referred to as spar varnish, but read the can carefully to see that it contains the UV protection that you're looking for. You will want to re-coat it every few years or when it get's scratched from use. Storing the boat out of the sun and weather prolongs the life of the coatings and is probably the best protection. Ignoring maintenance of the varnish or urethane on a bright finished boat is a sure way to ruin the epoxy or polyester resin that the fiberglass is applied with.

    For the interior, a curved scraper will help to get of the flaky bits and a very soft sanding contour pad will help you sand the interior. You'll still need to get up into the ends by hand if there aren't bulkhead panels with some sort of floatation or storage in the ends.
    "Anyone who says they like portaging is either a liar or crazy."
    - Bill Mason


  9. #9
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    Default Re: Refinish Cedar Strip Canoe

    If you're seeing greenish-yellow and whitish blotches that are not just flaking old varnish that sands off easily, and which look just as bad or worse when the area is wet, then you may be looking at delaminated and/or UV-deteriorated spots in the fiberglass (or possibly even impact damage). It's impossible to say for sure without at least getting a good photo to look at, but buying used strippers when you aren't very familiar with fiberglassing can be a very risky proposition. There are an awful lot of old neglected ones sitting around in back yards that would be more work and more difficult to restore and repair properly than it would be to start over from scratch and build a new boat (and possibly nearly as expensive). The $100, semi-trashed stripper is usually a great deal for the seller, as it saves him the trouble of sawing it up and carrying the pieces to the dumpster - but it is seldom a very good deal for the guy who buys it and has to do the work and spend the money to fix it up. It can be a massive job that still never ends up quite right. It would be very helpful if you could post some good-quality pix showing the problem spots so that we could give you a more accurate assessment of what's actually going on and how it should be fixed.

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