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just made a Concert sized side bender. I have thin sheet metal inside, for a liner and over the top (where the wood gets bent). Inside I have two 100 watt bulbs.

I did a test bend yesterday and the piece of wood came out quite well. I have some spring back but not too much for a first time.

I am curious how hot you let your bender get? I am putting a thermomerter in mine later.

also, How long do you leave the wood in the bender with the bulbs on? I first wet the wood, then when the box was hot enough that water boiled off when dropped onto the sheet steel, I bent the side. It took about five minutes to bend it into place. Then I left it in for about 10 minutes and turned it off. I turned it back on 20 minutes later and left it on for about 30 minutes. Then let it cool completely before removing the side.

It depends on the wood really. But most get the wood up to 275-310*F to start bending.

You want to measure the temperature at the wood and not inside the bender. 2 100w bulbs usually won't cut it for heat, when I had blubs for my bender I used 3-200w bulbs and that get everything nice and hot (didn't have a thermometer back than though).

Check out this artical by John Mayes on side bending to give you an idea of the range of bending temperatures.

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I have the longer insides of my bender covered with the same tin that's on the outside, but the short sides are uncovered. I guess I'll have to cover them as well, I imagine that 300 degrees would set something on fire.

Would a heat gun work to add the heat I need? On the test piece I didn't use anything ontop of the wood. I see that many people make a sandwich of something. I could wrap the wood in tin foil, then use a heat gun to heat the wood along with the heat from the bulbs..? My main concern I think, would be inconsistent heating.

Well, the heat gun doesn't work so well..

I Think if I used the gun to pre bend the waist, it would work. As it is, I tried to bend the wood with the gun while the wood was in the bender. I wasn't able to get the waist hot enough.... Plus, I think I'll soak the wood next time.

You need to read the several recent discussions on bending in the main forum! You'll find a lot of your answers. Specifically, I think 2 bulbs 100w will never do it. (I use 3 @ 150w minimum). Toss the heat gun.

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Dave
Milton, ON

This guy says he uses two 40watt bulbs...
http://www.ukuleles.com/BuildingHowTo/sidebend.html

Forget using 40 watt bulbs unless all you want to do is light up your sides. When I was using bulbs in my Fox style bender I used 2 x 150's and 1 x 100 bulbs and that was just getting hot enough to bend IRW. I now use a thermal blanket from John hall and swear by the thing.