Cold bending ribs! - created 09-21-2011

Polk, Doug - 09/21/2011.16:06:17

About ten years ago, Craig Tucker posted about cold bending violin ribs (I think this is still in the archives). At the time he swore by it and said he'd never hot bend again. His description of the advantages to cold bending made me think for a long time about trying it, and this morning I finally did. Unfortunately, Craig never said what temp the water should be, or how long (other then "briefly") to soak them. Logic dictated to me that the water should be hot, and the ribs well soaked, so I left them in (just under) boiling water for about five minutes.

What I got as a result was ribstock so distorted and curled that it was useless to try and place them in any kind of form or clamping rig. Obviously I did something wrong here. Has anyone else here tried this? And if so, do you have any advice as to soaking time and water temp?

Thanks!


Sender, Andres - 09/21/2011.16:41:51
Yis, I zeee--und do you drream zis every nicht?

C O L D

;-)

I haven't done it, but I remember that much--and the bending is done over a fairly long time span as I recall. I think he may have written some sort of update about it over at Maestronet.


McConkey, Jim - 09/21/2011.19:55:53
MIMForum Staff, Baltimore

Craig's Cold bending violin sides: no more cracked or broken ribstock [Pictures] discussion is still available in the Library.

"Finished ribstock is breifly held under water in a full sink then..." but he does not mention water temperature.


Polk, Doug - 09/22/2011.00:11:29

Right, he doesn't mention water temp or exactly what "breifly" means. Actually, I tried it again this afternoon with some more scrap rib stuff. I still used boiling water, soaking for only three minutes this time. The results were much better, but not perfect. Still, I was able to get the wood in my mold. It bent a bit faster then in Criag's old post. I took it out after just a few hours in the sun (95 degrees outside) and was surprised to find it nicely shaped without springback.

Still, it's not perfect. So Craig, are you out there anywhere?


Guest, Barry - 09/22/2011.03:35:28
A Fiddle is a violin with the elitism left out.

I recall Australia's most prolific violin maker using this process. I haven't tried it, but Harry Vatiliotis has been building for 50 years and trained under Arthur Smith, Australia's "Stradivarius".

A documentary made about Harry's craft called "The little box that sings" features many of his construction techniques, one showing him wetting ribs (water temp unknown) and then sandwiching the rib between a dripping wet cloth and a stainless steel band with a loop on one end. The rib mold was placed in a vise with one end of the "sandwich" secured with the mold, then he pulled the loop over and attached it to a hook attached to the side of the bench. The absence of heat was intriguing.


Tucker, Craig S. - 09/22/2011.11:44:57

Ask away.

I use a PVC pipe filled with warm water, and soak the rib stock (two at a time - orient the flames correctly!) for about three or four minutes, then start the bend, in a wooden jig and plastic (thin FOR SALE sign strips) strips so that nothing binds and as a "backing" of sorts - only bending slowly so that the rib material doesn't break - if everything starts to dry out, I will spray where I need it, with a spray bottle and warm water.

I haven't checked the past material here that I posted many years ago and so I will check it out and see if I think some new photos are in order...

Thanks Andres, for the heads up.


Tucker, Craig S. - 09/22/2011.11:55:23

Oh, and by the way, I still cold bend at least 90 percent of the time.

If I am going to make something quickly, or for a repair project where I can't use the forms - or even if I get ahold of some particularly difficult wood - I will still break out the bending iron, perhaps only for the CC bouts, which occasionally require a bit of help with old, or dry, or thick, or very highly figured wood.

So - don't toss out the old bending iron quite yet...


Polk, Doug - 09/22/2011.14:34:32

Thanks Craig, that was quite helpful! Answered my questions, but new photos would be much appreciated. Why the PVC pipe? To help keep the ribs straight? Or just more convenient?


Tucker, Craig S. - 09/22/2011.15:38:06

Just convenient.

I can soak linings in it, or ribs, or quickly dunk a small section of purfling - etc.

It's just greater in circumfrence than the ribs are wide. They sell perfectly fit caps for the end - so it's easy to water tight seal it, and I have a small hole drilled on the lip so I can hang it on a nail when in use.

And by the way, as a cheap, strong, shipment tube for bows, PVC works very well.


Polk, Doug - 09/22/2011.18:25:55

I don't mean to drag this on, but when you say 'warm' water, do you mean just under boiling, or say, as warm as most hot tap water? And how thick of a rib have you successfully bent this way? Thanks for the help.


Tucker, Craig S. - 09/25/2011.08:41:51

Yes, hot out of the tap is fine - I don't sweat the exact temp. much.

Usually my ribstock is right around 1/16" when finished and ready for the bend... That said, I don't set up the band saw to exact specs either, but by eye. Occasionally they are just a tad thicker - and the linings are typically about 1.5X the width of the ribs - or the same, if I want thin linings - BTW - you can easily cold bend linings also.

Good luck with this Doug.

I'm still looking through my photos (I'm quite lazy)- I know I shot some recent Cold Bend - Ribs and Linings photos...


Polk, Doug - 09/25/2011.12:42:32

Thanks Craig. I'll give it another shot tomorrow and see how it goes. If you do post other pics let us know.