Steaming Plywood

[schlaboatnic]

O.K, newbie question here. I'm on the downhill side of my kayak build. I need to make the covering for the rear hatch. The plans call for using 4mm Okume plywood and cutting stiffeners at a 24" radius. My particular problem is that I don't have any 4mm left, only 6mm I cut the hatch cover out of 6mm but it is a real bugger to bend into the 24" radius needed. I was thinking about trying to steam it to make the radius. Is this crazy thinking??????

[RonW]

Why not kerf the panel on the inside of the bend.

[JimConlin]

or run it through a thickness planer?

[Mrleft8]

If you were me, you might consider making a 24" radius bending form and making a bent lamination out of a number of veneer cut offs.

[P.I. Stazzer-Newt]

Radius :eek:
That would be 4 feet in diameter. Where on the kayak does that fit?

I think you could do that in steam bent ash.

[Hedzer]

the normal procedure for bending ply is to wet it out. Then bend it round an object like an oil-barrel, a drainage pipe or anything with te correct radius. Strap it tight with straps, or rope and leave it to dry overnight. The ply wil hold the bend. Be sure to overbend because the ply will strech itself a little when you loosen the straps. G.L.

[Cuyahoga Chuck]

I bent 1/4" 3 verneer plywood for kayak paddle blades using a heat gun. I was duplicating the old blades so I wasn't interested in any particular radius. Only a small band of the wood can be heated at a time so the operation is kind of slow. I bent the panels over the edge of my workbench.
The advantage of this methhod is that you don't have to guess how much springback will occur. You just go over the panel repeatedly until you get the radius you desire.
Charlie

[Don Maurer]

You could use the piece you cut out of the deck to make a flush hatch. You will need to make 2 half rings with an inside diameter about 1 1/2" smaller than the hatch hole and the outside diameter about 1 1/2" bigger than the hatch hole. Laminate the half rings to the underside of the deck to form a rim around the hatch opening. Then bend the pieces you cut out of the deck to the same radius as the deck and reinforce with cross beams inside. Don't forget to cut the cross beams short enough to fit inside the rim. Put 1/8" rubber gasket material around the rim, add turn buttons to keep the cover in place and you have a watertight hatch. Caution, sometimes these hatches seal so well that a vacuum seal forms when the air inside cools.