WFBustard
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Bending Dias Ribs possibly for Ouds
Hello all. I am new here but I wanted to post something interesting as my first topic and since I am putting my Oud build on hold thought this would
be okay for those interested in such things..
Recently I had been fooling around with older style guitars and thoght Id try to build one of those Belchoir Dias ones with the fluted back ribs.
I thought it would just be cool to build one, learn how to bend the beautiful ribs and then maybe adapt it into an modern style steel string design,
with an idea to lighten up the body.
I would like to say that I am no Luthier but a sculptor, trained designer/artist who likes to dabble in creative solutions to gain knowledge and
understanding of design and materials.
I was dismayed as I could find no info on the net for this process so thought Id better here.
I have used this process for other artistic wooden creations and have easily bent wood up to 2mm!
With more work on the pipe the radii of the Dias is easily made. After the Rib is removed from the mold it is quite stable and could be used for
precision work.
My wheel is part of an an old pulley from the scrap yard.
After a little research and development I have created the double-bent ribs and find that what seemed difficult is actually very simple and fast. Even
faster than hand bending a regular guitar on a hot pipe.
My Dias instrument, the first is not very good but there is still lots more to do and the first one of course is the hardest.
If there is anyone interested I would try answer any questions in regard to such things.
Since I am no luthier per say but an artist , I thought sharing the details might interest some who may have been trying to acomplish this design. As
you know in Art there is no true property, at least in my Philosophy.
Im sure there are those who may enjoy just seeing how I did it, taking the idea and running with it to create there own designs or copies of that
fabulous instrument or the Chambre Viheula.
A fine local luthier once told me there are no secrets, and I dont think there should be.
The method is extremmely fast and 100% effective with Two daily sessions on the pipe of about 10 minutes each created all the ribs shown in the
photo.
I just bent them like you would a side by spraying them with a little water, finding the right temperature and rolled them.
I trimmed them with a knife and the rebent prior to placing them in the mold overnight incase were are not quite dry.
It would be nice to see some of you fine luthiers, professionals, incorporate the fluted back ribs into some Ouds style instruments.
I beleive something very beautiful sounding and looking could result.
The thickness of this wood is 1.2mm for the Dias to allow for slight sanding to the final 1mm. It is flamed western Maple. I chose this because its
easy to bend.
enjoy, Im finding out that bending the ribs is the easiest part of this construction.
Thanks for looking! Hope some like it.
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Jameel
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Neat technique. A few oudmakers have done fluted ribs, but the flute is excavated from a thicker rib, not bent to shape. Bending across the rib to
this extent and along it would be quite a challenge.
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DaveH
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Fascinating. Stephen Barber, who I think is the most convincing on this, while he's cagey about his precise methods, gives the definite impression
that he's doing it without steam or chemicals in his Chambure vihuela copies.
http://www.lutesandguitars.co.uk/htm/cat14.htm
(PS - I love this page and the insight it gives into the scandals and rifts of the lute world!)
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DaveH
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Am I right in thinking you're heating the pipe and not the pulley?
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WFBustard
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Thanks-Yes the pipe was shaped to the radius of the Dias and a heating element from a cooking grill installed. I control the heat by turning it on and
off.
The thing was that when I was trying to develop the method I put myself in Dias's shoes.
I think Im pretty certain this was the method used by the originator.
I could be wrong but it seems to make sense given the local, the Kingwood wood used originally came from SA. Now thats a long time ago and sailing
ships were pretty big in the world.
What we find on ships...blocks and tackles, with wheels just like that one but probably made of wood.
The Lathe was top technology in those days.
In my research I veiwed many pictures of woodshops and round objects appeared everywhere.
I do not know what Stephan Barber does but I appreciate the Drawing he made in the 70's.
It is available from the Royal Collage of Music in England for purchase.
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jdowning
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Good for you WFBustard!
I look forward to following your progress on this thread with interest. Forum members should greatly benefit from this kind of individual 'hands on'
investigation - success or failure.
Of course, no luthier today has insight into the method used by Dias (although there are some clues from examination of the survivinig instruments) -
but if it works for you, go for it! There is likely to be more than one satisfactory solution to this question. As far as I know, Stephen Barber has
not developed the technology to bend fluted ribs for lute (or oud) or if he uses some kind of pre soaking period in a 'chemical" fluid (other than
pure water) to assist the bending of Dias geometry ribs. Did Dias - nobody knows?! Otherwise, the field is open for investigation.
Artisans of the 16th C would have had no problem in making a metal pulley (or mandrel) of the kind you are using. Metal working technology, to a very
high level, came with the Bronze Age (3000 BC to about 1200 BC), followed by the Iron Age. Also, the lathe is very ancient technology going back to
Egypt around 1300 BC.
So, no problem historically with use of rotating forms (like metal pulleys) - if that is how it was done.
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WFBustard
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Thanks for the encouragement. Yes hot pipe, simply a element from an electric grill, the heat is controlled by turning it off and on...
I think to acheive the precice Dias rib profile on an OUd shaped Rib is nearly impossible.
It might be done using compressed wood, I am unsure but probably. Comp-wood is expensive and it dosnt come in the more exotic flavours.
It is very difficult to acheive the greater long raDIAS for the Oud rib as the"flute" wants to flatten and does not like it.
I will begin by making the perfect Dias Ribbon which is actually tigheter than required and then try to bend it to a smaller long Ra"dias" . It is
long and rectangular and is 1.2mm thick.
I may line the rib with some support to try and prevent it from collapsing while it goes round the pip'. I was thinking a peice of rope or something
similar. I do expect some craking when this is done, but since there is no requirement for the width at this point I may be able to trim to shape.
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WFBustard
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I use a handle, a simple rod through the centre of the wheel at first to get the basic shape.
Then to get the wood to curl smaller than the radius of the pipe. I take the dry ribbon and squirt water down the centre, place it on the hot pipe and
quickly slide the wheel with my hand without rolling, this causes the ribbon to curl to a smaller r than the pipe, kinda like frying it, release the
ribbon and clamp it in the mold.
The small radius of the top of the Dias rib is...well quite a bit smaller than the lower bout.
A quarter is pretty good for me to gauge. After the ribbon is made into a rib by cutting with a knife and template it will lose some of its curl and
may require some touch up bending
Unfortuneatly on my initial trial instrument the two main "normal" guitar ribs(sides) were not quite up to snuff, or the arch long radius was too
small or a hundred other things patience and frustration come to mind, :-))
Anyways when gluing up the back to the sides I had to force joint about 32 of an inch, compressing the natural dome of the back a little, not
realising that this would be magnified into the arched back, this cause the ribs flutes to flatten somewhat...ahhh... but next time..
Not using a mold to assemble the back was the biggest mistake. I simply used the guitars sides. For the new back I will make two centre plates to
stand inside and support the structure, since the top is alrready on I will have to disassemble them and extract them through the hole...buts thats
another story.
That back will have to me romoved and a new back made.
A rare occurence, some light scorching has occured, although it can be sanded out, a ribbon this thin would not be advisable.
So for possible Oud shape ribs, I will increase the initial Rib thickness to 2mm to allow for this as I do not have a thermostatically controlled
device.
I will precut them to oversize in a leaf petal shape.
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WFBustard
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After numerous trials
I figure it is impossible to bend oud ribs and keep the Dias profile. Wood only stretches apx <1%.
If this is true then It can be done but the Oud would have to be as big as a volkswagen beetle-
yikes!
Using my wheel and pipe I did manage to get some 2mm thick maple ones with about a 2" radius.
I think that will have to do.
No sense in wasting more time and wood..
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WFBustard
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No Dias flutes for Oud but ribs to use(edited)
So heres the rib shape I could use for the Oud.
2mm thick ribs, I free bent them till they all looked roughly the same. I will do a bit of final shaping to get them as identical as I can and
assemble them into some kind of Oud like shape.
I will call this instrument the model "L" Oud".
It will have an EMG-81 active pick-up, steel strings and a Wenge neck which I hope to adorn on the maple bowl.
(just kidding)
It will have 2 roses,
the unsuitable 2mm rib: it can be seen to flatten out where the long curve is greatest...
Actually on second thought I think an oud with the curve of the rib on the inside would be a little more interesting...how much arch can be attained
if th longitudal arc were in reverse?
This would allow for a more naturalistic shape like the sections of a melon or gourd. A bit more traditional in some respects.
Ill see.
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WFBustard
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Well I destroyed another stave yesterday...it seems that puting the flute on the inside of the long curve is even more impossible than the outside.
Sorry no Dias dimension staves for ouds. So for now I will put my Oud on the back burner.
They would have top be shallower with about a 3-4 inch r.
Well back to building Dias 1581 # 2 which I think will be much better than the above trail build.
I have built a better mold and this time I will construct with more care knowing what I now know.
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DaveH
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Shame about the "pumpkin oud". I would have liked to have seen that, but I guess getting the same direction of curvature in both the transverse and
longitudinal directions is just going too far against the will of the wood. Keep us posted on the scalloped version though.
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WFBustard
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Yes well the pumpkin thing would be cool and the regular scallopped ribs are not too bad, but I was thinking of trying to soften the wood up a bit
with "super soft II" veneer softener to get more bend with less cracks.
So the pumpkin thang might still happen.
As for the softener Its made with diethelene glycol monoethyl ether as the active ingredient.
I havent tried it yet but got the idea from another luthier site.
Anyone ever tried the stuff?
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