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Capt's. Varnish

Discussion in 'Wood and Canvas' started by Chip, Feb 28, 2005.

  1. Chip

    Chip Curious about Wooden Canoes

    I put a first coat of varnish inside the Guide canoe today.

    Writers on WCHA forums suggested thinning the varnish for the first coat, and I did. I'm curious why the label instructions don't suggest thinning. What is the reason for thinning? I must say the varnish flowed nicely and was not running.

    It struck me as odd that the instructions on Captain's Spar Varnish state not to apply the varnish if the moisture content of the wood is below 15%. I figured the dryer the better. The canoe has been inside since December, so it ought to be about as dry as it is going to get without a kiln. My recollection is that it's unusual for air dried wood to get below 12%. I briefly considered wiping a wet rag over the wood, but then I figured since I have no way to measure moisture content I would just apply the varnish and hope for the best. Why do you suppose Captain's prints this prohibition on their label?

    Lastly, will somebody please tell me an easy way to varnish the sides up in the bow and stern? Brush only fits up there when held parallel to the sides, and it doesn't work too well like that.

    ~~Chip Walsh, Gambrills, Md

  2. martin ferwerda

    martin ferwerda LOVES Wooden Canoes

    For varnishing the ends of the bow and stern, I use a 2" foam brush, with the wood handle cutoff to about 2 inches.
  3. robert

    robert Enthusiastic about Wooden Canoes

    Although I am by no means an expert on varnish, here are my initial observations – it would seem a thinned varnish penetrates better, allows the brush to ‘flow’ well, this resulting in a better finished product with few runs, and as an added bonus; dust that shows up in the first thinned coat is easy to sand out.

    As for the under sides - I have been using an air powered spray gun (Lee Valley). Although if you take this route you have to be aware that mixing requirements change.

  4. Andy Hutyera

    Andy Hutyera The Red Canoe Guy - Life Member


    With regard to the thinning issue and label instructions: I recently attended a seminar by Bob Flexner who wrote the excellent book "Understanding Wood Finishing." In his lectures, Bob points out that unlike the food business, there is no regulation of finishing labels. He demonstrated many instances where the instructions on can labels were just plain wrong. In some instances even the description of the product was false. What I took away from this is to largely ignore the label instructions when they run counter to my own experience and understanding. In this case you've done far better to follow the advice given here. Flexner also recommends thinning the first coat 50% as a sealer coat.

    On the moisture issue I can only conjecture that perhaps 15% is a fairly low moisture content. The only reason I can see for this recomendation is concern of moisture driven wood dimensional change. If the moisture content of the wood is too low at the time of application the finish may not have enough elasticity to accomodate the dimensional increase in size when the wood is exposed to water as it inevitably will be in the hull of a canoe or boat. Just a guess.
  5. ebeeby

    ebeeby Novice Canoe Restorer

    You are right that the thinned varnish improves penetration. It is also an opportunity to detect cracked ribs that are hidden by sanding dust!

    But don't forget the human angle. Un-thinned varnish is used up faster than thinned varnish adding another quart purchase to the maker's revenue total.

    I used the, um, let's call it the "Miller Method", of 50/50, 75/25, full strength. It doesn't seem to matter if you cut it with turps or mineral spirits except to the nose.
  6. Dan Miller

    Dan Miller cranky canoeist Staff Member

    Nope, gotta pick someone else to name it after, I sure didn't come up with the thinning schedule on my own. (That's not to say I'm not honored by thought... :D ) And as well, I don't ever use varnish full strength; I thin third and subsequent coats roughly 10%...

  7. OP

    Chip Curious about Wooden Canoes

    Umm, yes. Only the cracked ribs were already obvious, and still are.

    If I knew what I was getting into, I'd either not have done it at all, or would have gone after those cracked ribs. As fascinating as this journey has been, it is not one I set out on. I turned down the "opportunity" to buy into this boat, only to have my paddling buddy, Steve, buy into it. He lives in a tiny townhouse in DC with no workshop to speak of, so he never even took the boat home. He brought it directly to my workshop. Neither of us knew jack about wood canoes, except I knew I enjoyed paddling this boat.

    There were a number of obvious breaches in the fiberglass skin of the boat. In our ignorance, we figured we'd just throw on a couple patches and be off paddling. I'd seen the cracked ribs. In fact, when we were using the boat on Moosehead in rough conditions, I studied the ribs and neighboring planking while we were pounding big waves. I couldn't see any movement at all. In the shop, the hull had no give, and we decided to ignore the cracked ribs. And so the repair has proceeded with no attention to the ribs.

    While working on the boat, I've come to appreciate it more. Now, I wish we had decided to reglass the whole hull instead of just patching, which was a big gamble to start with. And if we had the skin off and are doing all this work, we should have tackled those ribs, too. But that, I think, is a whole different level of skill, and if it means steam bending, another level of equipment I don't have. I can't even imagine removing the clinched tacks without tearing up the planking. So, at least for this go round, the cracked ribs are staying.

    The wisdom of the forum seems to be that fiberglass won't last too long, so maybe we'll have the boat in the shop again in the not too distant future, and we'll have another chance to tackle the ribs.

    Thanks all, for the varnishing info, and previous help with my other questions. Time will tell how she holds up to the rigors of paddling, but if nothing else the interior varnishing will look great when she comes out of the shop!
  8. MikeCav

    MikeCav Restorer/Videographer

    Today's varnishes are formulated thicker than those of a few years ago to meet current clean air standards. The ratio of solids to carrier is what determines the EPA rating. The manufacturers are required to meet the standards of various states (NY and CA, primarily) as well as some federal standards. Because they don't want to develop formulations on a state-by-state basis, they formulate for the strictest standard. It does result in a product that lowers VOC (volatile organic compounds) emissions and is better for the environment. That said....

    I thin the stuff! :eek:
  9. OP

    Chip Curious about Wooden Canoes

    After sanding and cleaning, applied the second varnish coat, thinned 25%. I'm really pleased with the way it looks. The varnish levels wonderfully and doesn't drip. On past wood projects (not boats), I've always used polyurethane, but I like the way this varnish goes on and think I'll switch for future projects. I guess this will be no news to you WCHA forum posters, since I am simply following your advice.

    To get up in the bow and stern where the brush won't work, I used a Shur-line trim tool I got at Lowes for $2.50. Its a spongie pad about 1.5" square with a plastic handle that slopes away at about a 40 degree angle. I may heat the handle and bend it a little flatter for the third coat. There is a layer of short, erect "hairs" on the working side of the sponge, almost like a velvet.

    I used the Shur-line on one of the thwarts to see how it compared to the Purdy china-bristle brush I used on the rest of the boat. I can't see any difference. I think this must be due to the self leveling character of the varnish.
  10. Dan Lindberg

    Dan Lindberg Ex Wood Hoarder


    There is a big difference between boat grade varnish and the usual hardware/home store stuff most people are used to using.

    Once you use the good stuff, it's hard to go back. :)

    BTW, I use a bristle brush for the insides and those foam ones for all the a trim, which I do "off boat". It's a lot easier to clean the foam ones. :)


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