Bending Wood

Ben M

Ben M

Active member
As I was bending the 2x4 keelson over the frames, I heard a crack. Of course, I stopped immediately. After some careful, slow application of pressure, I heard another crack and it came from the 2x4 keelson up toward the bow (furthest away in the attached pic). It was slight and there is absolutely no visible damage. I'm just wondering how much I can bend this board? It is a 2x4x12ft white board (fir I think) and I'm bending it about 6in. I don't think I've done any real damage to it. I just don't want to ask too much of it. There's also the issue of downward pressure (upward pressure once the hull is flipped) on the 1x4 cockpit sides as the full weight of the bend is on the center frame and then to the 1x4s. I guess once the hull planks are installed, the load dynamics will change. I just don't want to do anything stupid here.

IMAG1352.jpeg

 
Ben,
three choices.
first is to laminate it. Get two pieces of 3\4 inch thick stock and glue them together bent into the frames in the shape you want. This can be done with more than two layers but you need a pretty good saw to make the thin strips if they are really 12" wide.
Second is time consuming. Put the board out in the weather and bend it over a couple of objects that mimic the curve you want. Trick is to add weight to the ends slowly over time. Keeping it wet helps. This can take weeks.
Lastly is steam it. You create a steam source(Boil water so you can direct the steam into the Steam Box). The steam box can be any thing that will hold the board and the steam without building pressure. After a good treatment you can bend it right into the shape you want.
Give the plan designer a call. He may have a solution as well. That is a lot of curve for a 1 1\2" thick board without some help.
 
Ben,
I read your numbers wrong. I see you said 12 feet long not wide.
Are you sure the piece is calling for a 2x4. The notches in your frames look like they are for a 1 inch board. 3\4 inches planed stock?
The ply wood usually is flush to the frames when a boat is built. The 2x4 looks high in the notch by about half.
 
I agree that 2x4 seems a little thick to bend (not an expert, just saying).

To get wood to bend like that, you need to get a clear piece without any knots. I've bent long pieces of wood before, you can soak it in water, either throw it into a pond, or with rags for a few hours and balance it on something, with wieghts on either end, to bend it; kinda like a see saw. Hope that helps.

Anthony
 
Thanks for the help, guys! All these ideas take time . . . and I grew up with a microwave oven in my house, so I'm not much into waiting on things! Hahaha . . . Plus, I'm trying to get this boat ready to hunt by Sept!

SO . . . I went and bought two 1x4s and will attach and laminate them this evening. A lot quicker than building a steam box big enough for a 12ft long board! And a lot quicker than soaking the board . . . and waiting for it to completely dry before I do anything else with it. I'll post some pics later tonight when I get it in place so you can see your advice in practice. :) Thanks!

As for the frame notches for the keelson we're talking about bending . . . this is sort of a semi-V hull. The plans call for the keelson to be attached at the bottom of the V and planed/faired down to the angle of the frames, does that make sense? The part sticking out over the line of the frames will be faired down.
IMAG1353.jpg

When the planking is attached, it will lay flat on the frames and the keelson will have a V on the bottom to match. I've got a LOT of planing to do!
 
Got the two 1x4s attached and laminated last nite. Thank you so much for the help, guys! I really really appreciate it!!!

IMAG1356.jpg

 
it makes sence but seems like the hard way to do it.
Click to expand...

What's the easy way? Just skip the keelson altogether?

I kicked around the idea of trying to build her stitch & glue, but decided I'd be better off just following the plans straight on my first build . . .
 
hey ben m looks like you got it
i'm liking the look of your new boat
do you have plans/specs your working from if so from who
and do you have a pic of what the boat will look like when all done
thanks
 
Notch the bulkheads for a 1X4 and attach it..Plane the edges to the angle of the bulkheads and mark the centerline of the 1X4 (length wise). Rip a 1 1/2 or 2inch piece of 1X4 and attach it exactly on the center line. When you attach the bottom pieces to the 1X4 and just butt the edges of the bottom pieces against the 2 inch piece. Takes maybe 45 minutes to an hour and you don't break anything.
 
We bend wood with a piece of 4 inch cast and a tea kettle ,rags in the end ,tube from the kettle into the cast through more rags. work the piece hot wear gloves.
 
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