Wooden Boat People
By McKenzieDriftBoat.com
Guy's Wooden Drift Boat Project
Hello Everyone,
My name is Guy and this is my first post in this forum. I am here because I want to build a wooden drift boat and, undoubtedly, I will occasionally need advice of the pool of experts and experienced drift boat builders on this forum.
In preparation for this project I have read and studied three books: Drift Boats and River Dories by R. L. Fletcher, Boatbuilding with Plywood by G. L. Witt, and Covering Wooden Boats with Fiberglass by A. H. Vaitses. I have also developed my own set of construction plans based off of the "Original McKenzie Double-Ender with Transom" in Fletcher's book. I used and MS Excel spreadsheet to calculate all of the dimensions, cut angles, compound angles, and bevel angles of all frame components and I used Pilot3D software to calculate the as-cut dimensions of the plywood sides and bottom. At this point I am pretty comfortable with the mechanics of construction and I think that I am just about ready to start purchasing lumber.
Presently, I plan to use Meranti Hydro-Tek plywood; 1/4-in. on the sides and 1/2-in. on the bottom. I found plenty of places to purchase these materials, but they are all far away from Idaho Falls, Idaho, and as a result shipping costs more than the materials. Are any of you aware of a business within a few hundred miles of Idaho Falls that sells this plywood? I have a few requests in to the local lumber companies, but I have yet to talk with someone who has heard of this material before.
I also plan to use Port Orford Cedar (CVG) for the straight frame sections and White Oak (quater sawn) for the bent frame sections (chine logs and sheer rails).
Thank you, Guy
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Replies to This Discussion
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Permalink Reply by Guy Fredrickson on
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Phil,
I did not thin the varnish. This was obviously a big mistake. First, without any thinner added, it seemed thinner than the paints I was just using. So I didn't think it needed to be thinned. Second, because I am applying it over epoxy coated wood, and not bare wood, I didn't think the "penetration into the substrate" was as much of a factor.
I gave it a second coat tonight with the stiffer brush. I think that stiffer brush would have helped a lot with the first coat. I will probably let this cure and then do some scraping as you and Tungsten have suggested. Things seem recoverable.
Guy
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Here are some observations:
For the first coat, I did not add any solvent to thin the varnish and I applied the varnish with a (more or less) standard paint brush. The combination of having the varnish too thick (too viscous) and the brush too flimsy resulted in laying down a layer of varnish that was too thick and this resulted in many runs forming on the surface.
For the second coat, again, I did not add any solvent to thin the varnish. But I trimmed the bristles by about ½-inch to stiffen the brush. This combination worked much better and there seem to be few new runs.
So now I think I get it. When varnishing, the idea is to lay down as thin a layer as necessary to prevent runs from forming. This requires a combination of thin (low viscosity) varnish and a stiff brush. Undoubtedly, the reason it takes so many coats of varnish to finish the job, is because each layer is supposed to be relatively thin. Varnish does not go on thick like paint!
Oh… I ordered a set of curved scrapers to erase my mistakes.
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I’m much less distressed today than I was over the past few days. Today I tried the orbital sander, on slow speed, with 220-grit paper. This seems to work just fine for smoothing out the runs in the varnish. Pretty much, all of the inside surfaces of the side-panels need to be sanded. For some reason, the frames and rails fared much better with the varnish. A couple hours of sanding and I’ll be back on track.
Next time, I will thin the varnish with solvent and use a stiff brush.
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Permalink Reply by Stephen Markley on
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At this point I would be majorly stressed and would probably get Rick's Woodriver HVLP sprayer and paint the whole thing -- LOL
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Stephen,
I'm sure that I would not have been the first to make that decision after a couple coats of varnish.
Guy
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Permalink Reply by Richard Elder on
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Hi Guy,
I've never had much success using traditional oil based varnish over epoxy. Always ended up using a two part like AwlBrite although they are not the best for UV protection. If I'm using varnish I thin the first coat heavily to get maximum penetration into the raw wood, then build up to 10 coats to get maximum UV protection. Usually have to sand after every other coat. I've built up teak which has a lot of grain definition to the point where it is glass smooth. Then the secret is coating with high solids clear Alwgrip for toughness, but only after the varnish is fully cured--- like three weeks. The sailboat picture I posted lives outside, and with this system I spent about 10 hours a year on maintenance for 7 years.
Also for "the next boat" WEST makes a tropical hardner that has some UV protection.
The reason I prefer tape seam boats without ribs is because they are so much easier to maintain. I think if I had a traditional style I'd oil the interior rather than try to bright finish it and keep it up.
I see you are close by in IF. Give me a shout some time.
Richard
ps Its impossible to apply varnish properly with a junk brush. Look for a Purdy ox hair. Badger is my second choice if the cheaper ox hair is unavailable.
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Permalink Reply by Phillip Westendorf on
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Guy,
If the runs are cleaning up with 220 grit paper your better off than I guessed. Moving forward I'd consider using a roller on the larger area surfaces and tipping it with a dry brush along the grain of the wood. Consider sanding the 2 nd, 3 rd. and 4 th. coats with hand sanded using 400 grit both thinned and then go lighter on the thinner. You'll like the result.
To apply a thinner uniform coat I have used Mohair rollers (they hold up with the VOC's in the varnish) , 1" dia x ~5" long (~ $ 5 per two, available at a local paint store) They don't apply as much varnish as a brush as long as you don't over load it. Foam rollers from WEst System will work also but I prefer the Mohair. Keep up the good work,
phil w.
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Thanks Richard.
Thanks Phil.
I've noticed something. I don't get the really good advice until after I screw up something. : )
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Permalink Reply by Rick Newman on
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Guy, that's because you do such good work we all assume that you will once again forge ahead with wonderful, professionally done results. This may be your first drift boat but it isn't your first rodeo as far as craftsmanship, attention to details, knowledge and application of technology.You do a great job.
If you want to read more about the controversial world of varnishing go to WoodenBoat forum and search for varnishing, varnish brushes, storing and caring for varnish brushes, etc. It's an amazing body of knowledge and controversy with strongly held opinions.
With great respect;
Rick Newman
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Permalink Reply by Dave Barnes on
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Agreed. I thought my boat looked pretty good, but it's starting to look like jhsc (junior high shop class) material in comparison. We expect plenty of wood boat porn when this thing is done, since you're too far away to visit.
db
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Guy,
That's a ditto, I could not have said it better! LOL:)
phil w.
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Rick, Dave, and Phil,
Thank you for your compliments and encouragement.
The only thing worse than applying runny varnish, is then having to sand the runs out of it. But at least I'm getting close to being finished. I should be able to start varnishing again by next weekend. And I will make damn sure to thin the varnish and use a stiff brush. I don't want to do this job ever again.
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