Bending Plywood

[John in CC]

I was talking to a woodworker friend of mine recently. He has some curved solid oak chair back slats on his workbench. He told me that the key to bending wood was not moister or steam, it is heat. He had bent these seat backs with just a heat gun. They looked good to me. Don't confuse this with a hairdryer (it does look like one) this is one of those high heat don't do your hair with it type guns.

Today I was joining the two lower pieces at the bow. I clamped the plywood to the cradle and continues forward to the bow with the stitching. As I work my way forward the amount of pressure increases dramatically the closer to the bow I got. I rigged up ropes across the hull and turned a stick twisting the rope to pull the sides together...I did this in three spots and it worked pretty well until I got to the last few 5 or six inches. I then remembered the heat gun trick. After applying the heat the bow pulled together with just my fingers. I will be be using this again in a couple of days when I stitch the sides on!

Hope this helps someone down the line like the many posts I have found on the forum. Hopefully this is one of those gov back moments : ) Thanks guys!

[truenorth]

That looks pretty good!

On a heat gun vs. steam, just be careful not to scorch the wood and the fibers below or raising the temperature so high you affect the glue. You can get to a bending temperature in just a few seconds. You might want to apply a little water with a sprayer before the heat gun. This will help keep the scorching down. Solid wood is different from plywood and so requires a little extra care.

[DanaDCole]

Now you tell me! Seriously, this is great information. I've already done the hull panels (with great frustration) but there are places I can use this idea in future. I'll do some practicing on scraps first. I have a heat gun that has been helpful for removing excess epoxy. There has been some scorching even on the low setting and it happens very quickly so take Truenorth's advice and be very careful.

[John in CC]

Yes be careful with the heat! It really does not take very much to soften the plywood for the bend. I kept the heat gun moving over a large area on the outside of the hull. I was a bit surprised how little it took, it does not take long. My suggestion to future builders is to go slow and keep testing the increased flexibility of the wood as you heat.



^^^^I got the bow this far without heat without too much of a struggle. (notice I clamped the hull to the cradle) This is when I applied the heat. I was then able to pull the two sheets together at the point of the bow with just my fingers on one hand.

[craig]

That's impressive -- I didn't know that heat alone would bend wood so effectively. I will certainly try this technique in the future. The hardest part of the build so far was getting the lower breasthook installed; the second hardest was bending those lower panels into shape at the bow. Good solution to the problem! (Part of my problem is that I'm using Meranti, which is stiffer).