attaching ply subdeck

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Roberta
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Re: attaching ply subdeck

Post by Roberta » Sat Dec 22, 2018 7:58 am

I always test fit all the sub-decking before gluing it down. I use enough screws in strategic places to ensure it lays down properly. Re-fair if needed. I use the ring shank nails whenever I can, but if it takes all screws to get it right, that's what I use. I also would not trust just the glue, especially on a large boat. It is especially helpful to start in the middle of any deck panel and work your way out to the corners when test fitting. I start on the straight edges along the strongback and work out to the shears and framing. As panels are laid out you may see that the straight edge along the strong back may curve. This can be later trimmed to the centerline. Bending panels over the framing takes some adjustment to get them to fit nicely. Use clamps to get the panels flat to the mating surface before anchoring. These areas can be trimmed to the shears once the fit is completed. Even after doing cold molding on the hull, Glen L recommends a row of screws or nails to secure edges to the longitudinals. You don't want all the work on expensive materials to unravel.

Roberta
Roberta "Queen of the Boat Builders"
Built Zip "Oliver IV", Super Spartan "Jimmy 70", and Torpedo "The Glen L".

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Jimbob
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Re: attaching ply subdeck

Post by Jimbob » Sat Dec 22, 2018 9:58 am

My barrelback's plans called for a 1/4" subdeck with a 1/8" veneer for a total of 3/8" thickness. The 1/4" subdeck conformed to the underlaying support easily so I just used staples to hold in place until the epoxy cured. If you are using 3/8" subdeck, you probably will want to screw down especially on the edges next to the coverboards.
Jim
Jim Neeley
Building a Barrelback in Sacramento, CA
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Brian
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Re: attaching ply subdeck

Post by Brian » Sat Dec 22, 2018 8:35 pm

Yeah, it's a good feeling to know there is metal in the boat taking up the shear stresses. I like the idea of a few screws and then nails. As I thought about it more, it doesn't really matter if there are some slight imperfections in the ply from nails pulling it down into slight imperfections in the structure. First of all, I think my fairing is pretty good. But the finish planks are 1/4", glue only, so the will bridge any depressions, with epoxy filling in. I'm a "How many angels can dance on the head of a pin? guy, so I then to overthink everything. That's why this is Year 6 on my Monte Carlo! Hoping to launch at Lake Tahoe in Sept 2019.

When I pre-fit the two pieces that cover the rear deck (the barrel back), I screwed them down with dry wall screws. I can tell you from that test that screws are absolutely needed in 3/8" ply to make it flatten in the center and get it down all the way on the shear. Maybe nails would do it, but I doubt it. So I think it's screws #6 or #8?) in the center and shear, and nails everywhere else.

One thing I am going to do however, is to go to the guys who make epoxy here and ask them if there is a way to slow it down to give me more time. The problem is not so much on the boat, as in the pot! Once out of the pot, you have like an hour. I've been wondering, if you pour the mix immediately into a large tray instead of a typical container, so it is spread out, wouldn't that make the pot life longer? Billy, I'm also going to try your suggestion to avoid epoxy squeeze out, but I will probably err on the side of too much and have to get under there. All my Mahogany work under the decks is done, so I will tape up plastic to catch drips. Hopefully, I can get my old body in there and scrape off the residue while it's green.

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DrBryanJ
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Re: attaching ply subdeck

Post by DrBryanJ » Sun Dec 23, 2018 5:35 am

Brian, put your epoxy in something like a roasting pan to spread it out. Nestle that in another pan with ice in it. ( I use freezer packs that i get with my blue apron meals) The cold will extend the pot life.
Bryan

Building a malahini "Mona Lisa"

My wife said "If I build a boat, she's getting a divorce."

TomB
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Location: Holland, MI

Re: attaching ply subdeck

Post by TomB » Sun Dec 23, 2018 6:35 am

Brian,

It's easy to over-torque a small bronze screw, stick with #8.

I am a long way from sub-decking...but I'm an expert at making drips and runs...Have you considered epoxy in a tube to control how much you put down and mix just the right amount? Something like Thixo?www.jamestowndistributors.com/userporta ... ?pid=64347

Tom

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Bill Edmundson
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Re: attaching ply subdeck

Post by Bill Edmundson » Sun Dec 23, 2018 8:05 am

I have used aluminum pie pans. Pour your mix in one and nest it into another that you have frozen about 1/2" of water. I keep the resin and hardener in an a/c area of the house.

Thixo is expensive. I really like it for gluing to frames. It goes on fast. I spread it with a tongue depressor.

Bill
Mini -Tug, KH Tahoe 19 & Bartender 24 - There can be no miracle recoveries without first screwing up.
Tahoe 19 Build

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