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Greetings!

I am finishing a bending machine for a concert uke, and have bent the steel over the form in anticipation of attaching it to the contour of the form. I've just felt my way to this point as I have never made a bending form before, so am looking for advice on how to best attach the metal to the wooden form. The steel is just a mid-stiffness slat I bought at Ace hardware. I'm going to try to attach a picture of it.

I built a bender like that one for the Uke I made. I used nails along the edge to hold the steel down. I can’t remember if I punched the steel or not before I nailed. This leads to my next point.
The steel I used was thin (if it was steel at all). When I was doing this, I had somehow anticipated that the steel would provide some support. When I cranked the waist down, the steel creased and didn't support the bend. So make sure that you have supports where the pressure will be applied to the form. Look at the LMI site to see a pic of their fox bender where they use the bars between the plywood forms.

Of course you may have already done this. The bender looks good.

John

Thanks John! I thought nails might work. Galvanized? (because of the moisture in the wood during bending?). I'm really glad you mentioned the supports in the middle....I didn't build any in, and it makes sense that you need them where the pressure comes down. I think you saved me a big headache!

Beth

Be careful that the nails or screws that you use are galvanized because the heads can oxidize with heat and water and can stain the sides quite deeply. If your sides are wrapped in paper or foil the problem disappears and the bender doesn't get stained by the wood.

I use countersunk 3/4 screws to hold my aluminum flashing in place. If your mold is much over six inches wide there is a chance of the metal oil-caning out of shape.

That mold looks first class.
Good luck.

Bob

Bob,

Thanks for the tips and encouragement! Can I ask, what is "oil-caning"? I get the jist from context of the sentence, but it's not a term I'm familiar with.

Beth

Bob,

Thanks for the tips and encouragement! Can I ask, what is "oil-caning"? I get the jist from context of the sentence, but it's not a term I'm familiar with.

Beth

I use regular nails to hold mine down. Actually they were brads from a pneumatic nail gun, but they were not galvanized. I've had no rusting. The nails are installed along the edge of the form they really don't come into contact with the wood.

Beth:
Oil-canning must date me. The old oil-cans had a bottom that was dished outwards so that when turned upside-down oil could be pumped out by pushing the bottom and it would pop back when released. Oilcanning means dishing-in under pressure but popping back when the pressure is removed. It can lead to odd shaped sides.

Some usless information just for you.

Bob