The long, side-mounted back rest in the bow of a bow rider. Wood was rotted so I sent it to a car upholstery guy, who also happens to be a boater. He reuses the material and it looks great, but it doesn't fit! A touch too long. Quarter inch? Looking at the folds and such it looks like he sized it correctly. This bow curves so I'm thinking thats the issue as the wood is straight. I've got the board supported on the ends at the moment with some weight in the middle. Any suggestions?

Make a steam box. Put the section in it for an hour or so. It should be supple for about ten minutes to get into the right curve and place.

How thick is the wood?
I've had good success in wrapping a piece of wood in a hot wet towel, sort of the steam box effect. After 30-40 minutes, it became pliable.

I have not much experience in bending wood, but its my understanding that kiln-dried wood cannot be steam-bent, only "green" wood can.

But as I said, I have never tried nor confirmed this.

it's 3/8 or 1/2 I'd guess. What about balancing it on a towel rack in the back of a steaming shower? No direct water contact.
Should I drill vent holes in the back of this wood once it's bent?

Seabuddy..unless your talking about "Cool Hand Luke" I'm not sure what a steam box is.

If you can make a pattern of the curve you need, use clamps, or just use clamps to bend it in place. My dad has been working on a project that required laminating some strips of oak and he cut the necessary curve in a 2x10 and then fashioned some lateral bracing to keep the two pieces in a plane, and slipped the still-wet glued up strips into the curve, then used 14 pipe clamps to clamp the whole thing together and bend them into shape. The glue dried, and is holding the oak in the desired shape. Problem solved.

Laminating a curve is required in a tight bend. I've done the same with success, after a few tries. HINT: Your form is not impervious to the glue that bonds the laminate.

Is it like a full piece of plywood that you are trying to bend? You don't have much a chance at bowing plywood to hold shape for the same reason CJSDad's project held shape when dry.

Yes, full piece.

Pretty good article about bending wood, green and kiln dried.

http://www.danenbergboatworks.com/steam_bending.htm


And some steam box info and plans.

http://www.ceolas.org/instruments/bodhran/santin/MakeBox.htm

Depending on situations, lots of shallow parallel kerfs on backside, laminations glued using a form or steaming. For plywood, I would think kerfs or laminations best options.

Capn and HB...thanks. My buddy mentioned kerf cuts, but that kind of worried me. Lengthwise?

Are we talking a piece of plywood that the cushion is attached to??? If there were some screws or bolts to suck it up in the middle, it would hold a curve.

Let's save the wood bending steam baths for the restoration of classic sailboats, etc.

Yes, plywood backing of a back cushion. I'm assuming you mean push it in place and screw it. Tried it. Almost fits, but no. I'm not sure if bending it is going to make a difference, but it does need to curve. Might end up opening one end and grinding it for a minute.

You might have to kerf that plywood to get it to bend. To do that, you make a series of cuts about 1/16" deep on the back (the side you want to bend towards). The number of cuts and spacing are determined by the curve you want to effect.

I would also think that the radius of the bend will determine cut depth.