Jonathan
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Quick and easy rib bender.
Here's an easy rib bender to make that works great.
I had talked to a guy that builds side benders for guitars, and he came up with this. Really simple, but it works.
THe oud profile is made out of high grade plywood, about 2 inches thick, with 4 large holes to accept the clamps.
You also need a heating blanket and the two metal bending sheets.
With this, you can bend two ribs at a time, although it could easily be expanded to bend several more.
It is very quick, and very easy.
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Jonathan
Oud Junkie
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At the base, use a spring clamp and bring together, in this order: form, metal, wood, blanket, wood, metal.
I put a C clamp at the next hole.
1 minute after I turn the thing on, I start tightening the C clamp, and it is fully tight within about 30 seconds.
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Jonathan
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Now add the next two spring clamps. It is now about 2 minutes since you turned the thing on, maybe less
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Jonathan
Oud Junkie
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You can adjust the temperature of the heating blanket, but I don't. I just leave it on for another 3 minutes or so, or until I see significant smoke.
Then, I turn it off, and let it sit.
15 minutes later, I remove the ribs. If it looks like there is going to be too much spring back, just cook it a couple more minutes. I tapered the
form a bit so that it has a little shaper angle than I need to compensate for this.
Here is a bunch of quilted maple I did yesterday.
Fairly uniform. A lot more uniform than I was ever able to achieve with the bending iron. There are some slight differences due to differing lengths
of the boards in the picture, but you get the idea.
I had initially forgotten to "kick up" the wood in the back due to the 1 inch riser at the tail block. Ordinarily, it would not matter, but I don't
have much room to spare with this wood, so I actually redid them all. And not a single one broke, which to me is incredible (and it would be to you,
too, if you knew my track record).
I have bent about 20 ribs so far this way, and only my very first rib broke (I tightened that c clamp a bit too quickly).
I have even re-bent wood that I messed up earlier on a bending iron.
The super hard woods work great--maple, wenge, etc. Mahogany has more spring back, and burns easily--I may have to use the thermostat for that
wood.
I would recommend starting just bending one rib at a time just to get the hang of it.
I am going to find a way to bend the purfling, next. Maybe just somehow hold 20 or 25 purfling strips tightly between two pieces of hardwood, and
bend away.
I know some people don't like a bunch of machines, but I don't have any problem with this.
You can make the whole thing in about 30 minutes. The only real expense is the heating blanket, which will run over $100 (anybody have a cheaper
source for this?)
It is amazing how little wood I break this way--only one so far. Maybe it is because the heating blanket is heating up the entire length of wood
uniformly, rather than just the selective heat that you tend to get with the bending iron.
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Peyman
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Thanks for sharing the information. Can you also post what model heating blanket you are using? And what's the deal with "smoke?" is this smoke from
the wood or the blanket?
Regards,
Peyman
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Jonathan
Oud Junkie
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It is just a 6 by 36 inch silicone heating blanket. I think the company is protherm--i don't know if anybody else makes it.
I started to do some more mahogany last night, and I will admit that it is a bit more problematic. The wood bends very easily, but there is a fair
amount of spring back.
So, use the above numbers as a guidline for maple, and I will get back to you on the mahogany. Or, if you can figure it out, let me know. I think it
is going to need a longer cook time at a lower temp.
The smoke is from the wood. If I see smoke, I figure the wood is starting to burn, so I turn it off.
I do dampen the wood a bit before I bend it (not soaked), so there might be a very tiny amount of steam from that, although it hasn't been noticeable.
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Dr. Oud
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This is very cool stuff. or maybe I should say smokin'! I'm thinking the paper wrap and vent hole used in the bending tool videos at Taylor guitars is to solve the burning wood situation. Perhaps you just need to turn down the heat a bit. I would try to get the wood bent without
charring it since this will make the cellular structure brittle and more susceptable to cracking or splitting later. -very good work, though. I gotta
make me one of these things!
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