Jonathan
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Curving rib across its width
Didn't know how to title this one, and I am hoping that I can explain this well enough to understand. I thought I posted this a while ago, but I
don't think I got any response.
Any thoughts about bending the rib accross its width, as well as accross its length?
I am starting out with rib blanks about 1/8 of an inch thick--maybe a little less. By the time the bowl is assembled, and sanded, they will be a lot
less--perhaps 2 or 2 1/2 mm. So, there will be even less at the glue joint--not even 2 mm.
I know that this is how the great ouds have always been made, but I wonder if it would help to introduce a curve accross the width of the rib?
Nothing great--5 degrees or so. The degree would depend on the number of ribs used, of course. That way, it would not be as necessary to sand the
rib joints down to get a relatively smooth bowl. I know the bowl does not have to be perfectly smooth, and that the great ouds generally are not,
but why not introduce that curve into the bend initially so that less sanding will be needed at the joint?
It would not be that tough to do. I am using a very simplified bending apparatus. It amounts to a form of the oud profile, measuring about 2 inches
thick. Then, I sandwich the metal that comes with the bending iron (stainless steel??), a slightly damp rib blank (not soaked), a heating blanket,
and another piece of metal. I have holes cut in the mold so I can use c-clamps and spring clamps to hold that "sandwich" in place to the mould. I
let the sucker cook for 4 or 5 minutes, let it cool down, and it is done. And, every one turns out uniform, with no cracking. Even the most
difficult woods seeem to bend with ease like this.
It would be pretty simple to introduce that curve that I was talking about--just file or sand the top of the form to taper it to that 5 or 6
degrees.
Any thoughts would be appreciated.
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Hosam
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The rib curveture is good idea if the number of ribs for the oud between 13 and 19. If you have 21 ribs or more it will almost make no difference.
Can you please post some photos?
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Jameel
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I hope you try it Jonathan. I'd be interested in your result. I've been doing quite a bit of research lately on bowl shapes and techniques, consulting
with lute makers even, and I've discovered some interesting techniques. I'm trying them out right now on an experimental bowl. I would think that
you'd only have to curve the area of the rib at the widest point, tapering back to flat quite quickly towards the tail end (like only an inch or so,
since the plane of the ribs here changes so rapidly to being virtually flat to each other) and more gradually towards the neck, maybe for 3 inches or
so, since the narrowing of the ribs here negates the necessity of the curving. Lute ribs are typically 1.5mm thick and down to 1mm for tropical
hardwoods. Then again, lute ribs are kept flat to each other in wide-ribbed bowls, so there isn't much chance for post-construction curving. This
makes a good argument for your idea, since if the ribs were curved, they could start thinner. Lets see the results Jonathan.
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Jonathan
Oud Junkie
Posts: 1583
Registered: 7-27-2004
Location: Los Angeles
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Thanks, guys.
Jameel, you are right. I had not thought of that. The curve would only really have to be at the widest portion of the rib.
I will try it, and let you know what I come up with. I just hate having an area of only 1 mm with glue. And, on a lot of older ouds, of course, the
ribs separate from time to time.
Bending the ribs with that heating blanket really makes a lot of things possible. For whatever reason, by heating up the entire rib with the blanket,
I have no problems at all with breakage, and I can bend the rib much more quickly.
I have been doing a bit of reading on lutes as well. I picked up a copy of Lundberg's Historical Lute Construction, which is a pretty fascinating
book. There are a lot of differences between the lute and oud, but a lot of the ideas can be applied.
Thanks again.
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