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Peyman
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Hi Jonathan,
I don't know if this is of any help. There is a method that I am using to build a kamancheh and a setar which have ribs. It's a bridge-mold method.
You draw a series of "polygons" and put them on fiber board, that represent the inside graduation of the instrument. They make it easy to see where
your ribs go. I learned it from a setar building book and also a brief description apears in GAL volume 1.
Check out the picture (no this isn't a torture device). The fiber boards are hard to see. You fill around them with whatever wood you got and use
hooks and rubber bands and the wedges to hold down the rib. You start placing ribs from the sides. For the last rib, you take a piece of paper and
measure the place where it should go and make it fit.
I am not sure if this method would work for an oud. This setar soundbox is 27 cm. I was thinking about making a small oud with this method.
Hope this helps.
Peyman
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Jonathan
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It does help. I hate to get sidetracked on this thread, but this has been occupying a lot of my time over this past month.
I like that device. My problem is knowing how much pressure to put on the rib. I am assuming that you put the rib in there wet? It seems that they
tend to crack as they dry.
My father told me that, when his father made ouds and lutes, he soaked the ribs over night, and apparently pressed them in steel moulds (perhaps a
series of them), and then literally cooked them in the oven. I have seen his ouds from the 20's and 30's, and they have all held up really very very
well. The idea is appealing to me. So, I did make a series of moulds, but I have really wasted a lot of good wood. As the ribs dry, they crack on
me. I guess I am trying to bend too quickly. Still working on it. I picked up a couple of books on wood bending, but no new ideas.
Thanks a lot for the picture. It seems like it would be applicable to an oud.
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Peyman
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This mold isn't for bending. It's a guide for making sure all the ribs are the same size and have the right bevel, even though you could hold the ribs
in shape with a series of them.
I have had the same problems as you do with bending. What I noticed was that the ribs that were inconsistant in thickness cracked. So I got a wagner
safety planer for my drill press. After planing I use a scraper and a 60 grit abrasive paper to make them flat on both sides. It's worth spending the
time here. Also the thickness has to be around 3 mm or so.
I tried to bend them dry but no luck. I don't know how Dincer and Jameel do it. So I soaked them over night. The walnut bends like cardboard with some
heat. I use a pipe with a heat gun. There is also another way of doing it which is what they used in the old days and that's to soak for several days,
then with clamps they simply bend them over a form, letting them dry for a while which is similar to your grandfather's method. But they didn't put
them in an oven.
If you need more info on the mold let me know. I can send you more pictures of the molds and the bending forms.
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Hank Levin
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I'm having a LOT of trouble understanding the difficulty you guys are having bending ribs. First of all, in my experience (which includes about 3000
dulcimers, each with 4 bends per side) as well as ouds and lutes, I found that soaking the would caused any wood with cross-grain (which includes all
figured wood) to disintegrate when bent.
Second, I previously posted a system for bending ribs dry, with just a "brush" of H2O on the outside of the bend immediately prior to bending, a light
touch to the hot iron of the outer surface (to vaporize the H2O you just brushed on), then flipping the rib over and bending it. Most can be bent
rather sharply, and those that have a tendency to splinter can be coaxed around the iron by putting pressure with a wooden block immediately over the
"weak" spot. You should thus be able to bend even a rib that has a knot or other weakness in it, though you will normally try to avoid these when
cutting the ribs.
Taking the bent rib and rubbing it against sandpaper that's been spray-glued to a flat table top (or board) will give it a fine anged surface to
connect with its adjacent rib.
How much pressure to use in gluing? Only enough to make firm contact---which is really very little. You can use patches of newspaper dipped in thin
hide glue and pasted along the joint in critical places (it will pull the joints really tight---you scrape it off later), or just masking tape will
work too.
This system also works with three strips of purfling between each rib, Karibyan style.
What am I missing here?
Fondly,
Hank Levin
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Peyman
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Thanks Hank. I think my problem is inexperience. I'll give your method a try tonight. I haven't had any disintegration with my method.
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Jameel
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Ditto what Hank said. Before I made my first oud, I never bent a piece of wood in my life. I think you guys are not letting the wood get hot enough.
My bending iron is hot enough that when I sprinkle some water on it, it literally bounces off. It should be VERY hot. Notice some of these pics and
videos from the middle east of luthiers bending ribs freehand over an open flame. The wood is getting HOT. No water is really needed. Make sure your
ribs are not too thick (mine are 2.5mm or so). And let the wood tell you when it wants to bend. When it gets hot enough it will bend readily without
cracking. Ideally, ribs should fit against the previous rib with no pressure, just enough to hold the rib in place. You don't want to build tension
into the bowl.
Hank, I was under the impression that clamping hide glued joints after the jell stage is pointless, since the glue can't squeeze out and pull the
joint together further. If glue-soaked newspaper pieces draw the joint together only as they cool, jell, and cure, isn't that too late to draw the
joint itself tighter?
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Jonathan
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It is just that, if it were possible to form a mould, that the wood blanks could be inserted into, that was gradually tightened over, say the course
of a month or two, such that each rib was uniform and created essentially without labor, I would love to find it. Or design it. Or build it. You
get the idea.
Probably impossible.
As always, thanks for the input.
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Hank Levin
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Jameel,
Whoops, you're right about that! (I've actually only used mechanical pressure along with tape. See Robert Cooper's book on lute making.) What was done
traditionally is to place the glued paper patch and immediately force-dry it with a hot iron held above it. (That would be an old-style heavy
soldering iron heated in a small furnace. We use to use them in high school metal shop---really clumsey things, but great for force-drying glue.) The
technique is described in Musik's Monument by Thomas Mace, an incredible book that may be available in facsimile issue. It has lots of stuff about
lute repair and playing. I don't remember the date on it, but it was written just before the lute disappeared from the scene in Europe.
Hank
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Peyman
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Thanks Jameel and Hank. That method worked! 2.5 mm thickness is the best. I held the spot to be bent with my left hand over the pipe and once I felt
the heat coming through, I moved the rib about 1/2". Once again when the heat came through, with right hand I pushed down a bit, and the rib started
to bend like a copper wire. It was easy. My mistake was not being patient. Also I didn't hold the rib at the ends because that leads to cracks.
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Hank Levin
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BTW, if anyone's interested, abebooks.com has facimile copies of Mace's book starting at $50…and going WAY up.
http://dogbert.abebooks.com/servlet/BookDetailsPL?bi=440475934&...
Hank
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Jameel
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Hank,
Interesting info, thanks. I've used the hot iron technique to quick dry hide glue, but never on the bowl. I also used an iron from the hobby shop
designed for affixing labels. Works great and they are only about $25. The same item from a luthier supply is way more.
Payman, glad it worked out!
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Hank Levin
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Good idea about the labelling iron. I would not hesitate to speed the drying on the patches, but I don't think I'd trust it on the main joints
force-drying them. Just a guess. --Hank
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carpenter
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I have a Coverite iron, with handy heat setting knobbie - a model airplane item for covering wings. Worked great on heating up the hide-glued rib
end/bowl joints. Dial in the heat setting on a scrap...gets hot enough to scorch light wood.
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Jonathan
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OK, on to the rosettes. Wasn't sure what to use, but this Abalam material looks awesome. Some sort of synthetic abalone. It comes in a lot of
different shades. It is really hard to get a picture of it, because the colors change so much with the slightest movement. A lot of turqoise,
greens, and a tiny bit of pink. Unusual, but there are old ouds out there with abalone roses. I am even thinking of using it to make an incredibly
thin ring for the purfling around the roses. It would have to be super thin, though, and I am not sure how well this stuff will cut. And, I would
probably use a much softer shade if I decide to do it, so as not to detract from the rosettes. Some are just a nice, pearlescent white. Might be
cool to have a thin, thin, thin ring of that.
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Jonathan
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Now for my lazy man's approach to the rose.
I took a picture of a rose that I liked. I printed it. I fiddled around with it on a copier until it was the exact size I needed.
Then, I sandwiched the abalam between particle board, and pasted the pic of the rose on top.
Then drilled in the holes, and started to get at it. Until my eyes started to give out. I can't do this for too long at a time, because it is kind
of tough on the eyes.
In the pic below, you are looking at the picture of the rose glued onto the particle board. The central section of the rose is completed. I am dying
to see what the abalam looks like under that wood.
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Jonathan
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For the small eyuns, I had planned on using that pattern with the small bird--pretty common old-school thing that I love (there's an example of it
below).
But, I think that the abalam might detract from the bird, and make the bird not even noticeable. So, I may end up just going with a geometric
pattern.
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Jonathan
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OK, I know I didn't wow any of you guys with that abalam stuff. You could be right. Anyway, I am going to keep going with it and see what happens.
In the meantime, I tasked it up behind my face to see how it would look.
I am not done with it yet--still have a bit of carving out to do, especially at the outer portion of it.
The bold pattern does detract a bit from the design, unfortunately. I could dull it down a bit with a super fine sandpaper, I guess, but I think I
will leave it like this. For the purfling, I am just going to go with the simple purfling strips, or else the whole thing is going to get way too
loud.
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Jameel
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Jonathan, glad to see you making some more progress. We can't wait to see it finished! I'm not crazy about abalam for roses, too busy, but I do like
your pattern. I'm curious how you are going to cut the mortises for the hole purflings now that you've removed any center point. Have you developed a
new technique we should know about? I'm attaching a pattern for the bird roses you mentioned. This is from a Nahat oud.
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Jonathan
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Jameel, I am not sure about it, either. I might even dull it down a bit with some fine grit paper. The back side of this is duller, and I almost
think it might look better.
The problem is that your eyes can't focus on the pattern because it is so busy.
The more I think about it, the better that sounds. I will dull down a scrap of this stuff, and post that, and see what you think.
This stuff was nice to work with, though, and it is fairly light weight.
I still have that mircata. I might even scrap the rose above, and re-do it with the mircata. I have to sit on this one for a few days and think
about it. It would be hard to scrap something that I have already spent that much time on, though.
As far as the purfling channels:
I mount this face onto a thick slab of wood that has the three center points, and the circumscribed line where the holes are. I initially used that
board under this face to cut the holes. I used one of those hand hole cutters (not the one that is attached to a drill). So, the holes are there,
and I can tell where to line up the face.
Hopefully, that will work. This face is bigger than the final face, and I tack it down with small carpenter nails--it has not been a problem.
Fortunately, the wood has not split at all. Don't look to me for new techniques. I am just trying to get through this with all of my fingers.
I love that bird. Beautiful, Jameel. Thank you very much. I don't think I will use it this time, unless I switch to the mircata.
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Jonathan
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I love that pattern, Jameel. Now I realize that those are grapes on a vine. A dove, grapes, vine. A lot of religous imagery that I don't think is
an accident.
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Jonathan
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You had me stressed, Jameel, so I figured I better start on the purfling.
Here's the board I was talking about.
I had initially cut the holes on this board, so the center marks were already there.
I have put in the purfling channels. I used one of those hand hole cutters. It just pivots around a central dowel, and you turn it by hand. I like,
but next time, I am going to put a mark on the blade at 1mm. The only problem is the fear of going through the face. The spruce is 2mm, and the
channel is supposed to be 1 mm, so there is not a lot of room for error.
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Jonathan
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I decided to use some 3 band purfling strips (black/white/black) that I got off of lmii
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Jonathan
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This step went fairly well. I like the way it turned out.
I bevelled the inside edge of each of the soundholes--I like that look a lot better than simply leaving it squared off. It caused a small
irregularity on the central soundhole at 1 o'clock, but otherwise, I am pleased.
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Jonathan
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I roughed up the back of that abalam with some sandpaper, and gave it a matte look. Might be better like this. The flip side looks the same as that
initial pic of it that I posted. I am not that happy with that version, but this duller version I might be able to live with.
Again, I still have some more carving to do on that rosette.
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SamirCanada
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OH! nice...
I like it much better like that. Not as much glitter going on.
Noice work on the purfling too!
Good luck for the rest!!
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