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Jimmy_Hill

bending ribs?

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ok so ive ruined about 25 feet of ribs so far and ive decided to stop being stubborn and ask on here. i soak the ribs for maybe 20 minutes, set my bending iron to 4 or 5 untill the water bounces off. then i procede to bend my ribs, so far i havent gotten past making a simple c bout.

is there a way to make metal forms to heat up in the shape of a violin. i get tons of springback the next day when i go to clamp and glue it into the mold and im having a hell of a time trying to get the desired c bout shape.

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Do you use a bending strap?

How thick are the ribs?

Perhaps your technique is not quite there: the part of the rib you want to bend needs to be heated properly against the flattest side of the bending iron before you slide it slowly around the tighter bends.

I don't soak the ribs, I just wet them on both sides to help heat distribution. I also put a folded wet paper towel between the rib and the bending iron.

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Don't soak you're ribs, Jimmy. Never, ever. When I have my rib stock in the bending strap, and am ready to go, I just dip a finger in the water and give the stock a quick wipe. It's moist, at best.

Don't think of water as a wood softener, all the water does is make the heat travel faster through the ribs. Which means you need hardly any at all. Ribs are thin, the heat will travel from one side to the other fast.

Make sure you're ribs aren't too thick. They need to feel flexible before hand.

The spring back will disappear once you stop using a lot of water.

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Jimmy, I have posted this same question in the past. The most important suggestions I can give you are:

1. The iron must be hot enough

2. The ribs must be thin enough (particularly for the C-bouts) But not too thin (no less than 1mm.)

3. Clamp and glue the little bastards right off the iron. Don't let them sit over night - they will straighten up on you.

What you do before bending is SOO much more important than the bending itself. Make sure your ribs are prepared and consistent!

CB

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yes, jimmy

my method may only be applicable for my "one peice" ribs

others will have effective methods

its seems you are around some qaulified luthiers

perhaps one of them may be able to show you?

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Hi Jimmy,

I'm just making my first one and had troubles with rib bending, too. I think it's just normal so don't worry. The most important hints were already given. My first mistake was that I left the ribs too thick (1.2 to 1.3 mm). I planed them down to 1 mm (don't make them any thinner as CB already said) and they were much easier to bend. Steam the end with a moist piece of cloth for a short time. If you soak them, you'll get distortion and spring back. Jacob already explained the procedure. I've only one point to add: Rib bending should be fairly fast. The rib will become very brittle if it takes too long. There is a certain "point" when the rib becomes "soft", try to feel that moment and use it to bend the rib quickly.

You can clamp the ribs to the mold to allow them to dry and glue them later.

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I use a thick piece of leather between my fingers and the rib. My fingers are directly at the bending point. I move the rib back and forth until I feel the softening point. We could use a good video on youtube, but I don't have a camera.

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Don't waste materials, it's the worst thing you can do appart from injuring yourself.

Pretend your materials are all you'll ever have, and don't hurt yourself.

Ribs.

Prepare them by cutting to width but leave some extra length for trimming.

1. scrape them down to 1.4mm

2. sand them with wet and dry 400 grit, used wet down to 1.2mm

3. use a hot iron.

4. use steam, produced by soaking a towel in water, then apply it between the rib and the iron.

5. whilst steaming, bend the rib with a spring steel strap with handles.

6. removed the steamy towel and finalize the shape on the iron.

7. See that it fits the form and the block shapes perfectly.

8. Turn off the iron

9. Have a beer or a coffee.

10. You can now bend violin ribs, have a go at violas, but dont try 'Cello ribs until you are more confident.

Cheers. :)

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I've used alot of different materials as a bending strap.

The one I keep coming back to is lead flashing.

You can find it with a little searching.

Very flexable and it offers alot of support.

And, to say it yet again, don't soak your ribs.

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any tricks to clamping corner blocks to ribs?

Try clamping the ribs to the blocks.

Over the last week there have been many posts on that exact subject, Jimmy, just do a little reading, perhaps make a few prints for workshop use.

Good luck.

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