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Permalink Reply by Rick Newman on July 28, 2011 at 9:23am

The major purpose for a sealant/adhesive between the frames and plywood skin is to seal the holes caused by the screws. There is a great deal of andecotal evidence that shows that water less frequently enters a hole that has been sealed with something that flexes with hull movement. When water enters the wood often bacteria also enter, the same bacteria that can form "dry rot".

 

Another part of the concern often discussed is that adding an adhesive between the frame and plywood adds strength to the overall build. From where you mention you are going to boat I would have to assume that the point of highest stress your boat will commonly see will be unloading and loading.

 

Based on this a commonly available sealant such as Loctite's PL Polyurethane

http://www.loctiteproducts.com/p/17/26/pl_seal_dws/overview/Loctite...,

which is available at the big box stores should work fine. It is also not as messy as epoxy. The smaller the hole you cut in the spout the finer the line of adhesive you will apply.One thing you might do to confirm that you want to use this product is to do a few practice joint that resemble the different joints in your boat and test them to confirm they work for you. Build them, let them dry the recommended time and then test to see what fails, the wood or the glue. This will also give you an idea how much adhesive you want to apply to ensure that your screws will actually go through the adhesive.

 

Epoxy is heat sensitive, so a cheap heat gun from Harbor Freight and a putty knife can help if carefully used. Round the end of the putty knife so if you slip you won't create a big divot.

 

Good luck with your build, keep sending pictures!

 

Rick Newman

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Permalink Reply by Ron Bakken on July 28, 2011 at 9:50am

Thanks Rick!  We will test the Loctite PL.

 

Do you have an opinion on whether we should seal the interior with epoxy or not? 

 

Not a picture of my son or I but of a friend who guides for the Hayward Flyfishing Company.  This is what we are after. 

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Permalink Reply by Rick Newman on July 28, 2011 at 10:32am

Epoxy would seal the wood in a general sense, however several issues occur as the boat is used and flexes. If movement or damages or failure to get every single surface covered water can enter. Then potentially so can the bad organisms. Plus epoxy needs to be covered with a UV resistant film, for example, varnish, polyurethane or something similar if you want a clear finish.So your initial expense and maintenance costs for more coating can add up. Does it look great, yes.

You haven't mentioned what type of plywood you are using, Douglas Fir has the habit of "checking" or different rates of expansion and contraction between the now exposed growth rings. Look at an older piece of Douglas Fir plywood that has been left uncovered to see what I mean.

 

On the other hand an oil treatment, (see the search engine for {boat soup}) is much less expensive, lower maintenance and allows the woods' beauty to show.It won't take you long to apply the oil, just make sure that don't leave any puddles, wipe up the extra.

 

So that's my opinion, I know that there are others. Do a search on this site and you can probably spend an hour or two just reading all the other opinions.

 

I am going to try the Penofin Marine oil treatment on the frames in my build. The Sapelle sides are laminated with S-Glass and epoxy. I need to add an additional coat of epoxy and then I plan to spray a polyurethane clear gloss on top of that. I am pre-finishing all the wood before I assemble my drift boat. I live in Washington State and plan to use the boat in some whitewater rivers, at least some rivers with mid-river rocks and obstacles. My concern is reducing the amount of damage that might occur if I hit an obstacle. Having the S-Glass laminated to the inner sides should help with that. It still will probably fracture but hopefully the wood and glass will hold together or only require a duct tape repair to get off the river.

 

Again, good luck with your build.

 

Rick Newman

 

 

 

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Permalink Reply by Ron Bakken on July 28, 2011 at 11:50am

Very helpful Rick!  Thanks!  I like the sound of less expense, lower maintenance and beautiful wood.

The ply we are using is called ACX. I think the outside layers are pine.  One side is sanded and free of any knots or checking.  It's recommended for exterior use.  $25 a 1/2" x4x8 sheet.  so not a high end ply but should look good oiled.  The frames and other wood is clear pine.

 

Prefininsh the wood before assembly?  Interesting!  Sounds like your building a fortress.

 

Ron

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Permalink Reply by Jonathan Clarke on July 28, 2011 at 12:47pm

Glad to see another Cheesehead with a wooden boat jones.  I'm in Hudson.  It's a small world - I was in your friend's boat this past Monday.  No muskies, but lots of nice smallmouth.  Your friend is very good at his job.

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Permalink Reply by Ron Bakken on July 28, 2011 at 1:04pm

Very small world Jonathan!

Cory is awesome. My son is good friends with him and we spend a fair amount of time in Hayward. We did a fly fishing for Musky trip with Cory last fall. My first time on a drift boat. caught 2 smaller fish and had a great time. My exact words to my son as Cory hauled his boat out of the water were "David, we are selling the walleye boat and getting a drift boat." So boat sold in April, 2011 and started this build in May

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Permalink Reply by Rick Newman on July 28, 2011 at 2:33pm

I am applying my paint and oil while the wood is laying horizontal. No drips, no runs, no crawling around upside down to apply finish.I purchased a HVLP sprayer from Woodcraft to spray on the varnish for the plywood pieces and the polyurethane finish. Already had the compressor. I am hoping that my skills are up to the task.

Maybe not a fortress but I have analyzed the problems others have had with their boats and repairs and tried to anticipate the needs I might have. The bottom of my boat has a layer of S-Glass on the inside and a coat of epoxy to fill in the pinholes and such. I will next cover that with a couple of coats of oil based porch paint. After the boat is assembled I will add a layer of 18 oz E-Glass more epoxy with graphite powder mixed in.  I know it won't be bullet proof but it should be tough.

 

Rick Newman

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Permalink Reply by Kevin C. on July 28, 2011 at 4:56pm

apply light heat with a heat gun to excess epoxy and use a good sharp scraper to remove any excess,don't epoxy your interior,just oil and use a sealant for your rib to side panel connection ,I prefer 5200.

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Permalink Reply by Ron Bakken on July 28, 2011 at 5:40pm

Thanks Kevin!  I appreciate your input.

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Permalink Reply by John Greenleaf on July 28, 2011 at 8:47pm

Ron, I am also a big fan of the oil finish and I also really like the 5200 stuff - it is truly amazing - flexible and bonds like crazy, but a couple words of caution regarding the 5200:  a) its pretty expensive b) it has to be cleaned up immediately with mineral spirits or else it is there forever (and you thought removing excess epoxy was bad..) and c) if you get it on your clothes, skin or hair...plan on having it there for awhile. Other than that, its awesome. John G.

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Permalink Reply by Ron Bakken on July 29, 2011 at 5:06am

Thanks John! 

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Permalink Reply by larry Hambley on July 29, 2011 at 9:26am

Ron:  I am certainly no expert but using 1/2" ply seems to add a lot of weight that is not needed. If you are fiberglassing the exterior, 3/8" or 1/4" should be plenty for the sides.  I also believe that by not using marine plywood you will have to be very careful to keep the boat dry in storage to prevent dry rot.  

I like the keelson as it will add some stability and strength. 

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