Heat

[Regis]

There has been an interesting recent discussion about heat treating bridges. There have also been past discussions about heating or not heating coatings and of heat vs cold bending of ribs.

Has anyone tried or read about heat treating the plates? I sometime wonder if tanning in the sun qualifies as heat treating? Does it have any tonal effect?

Regis

[Jacob]

This remains an interesting topic to me. "Baking" of the plates a-la-Vuillaume has been mentioned often, as well as the ill effects caused by the process. What has not been mentioned is "boiling" the billets prior to carving - aparently this has/is being done by some, also will salt of some kind added. I've been wondering what the effects of such "cooking" or "stewing" would have on the wood.

[Mauricio]

Again I'm with Jacob, this also intrigues me.

One of the thing that keeps me only "intrigued" is that I have been able to try some Vuillaumes from the period which he is thought to have baked his wood (1850s?), and the sound was as harsh and dry just as one would imagine the sound of a burnt violin. But let me emphasize that this is only the impression I had, and besides not being sure that any baking or any other treatment (acid?) was done at all, the sound qualities of this violin could also be attributed to many other factors.

I've also boiled a spruce top in a solution of borax, but I have not used that particular piece yet (during the drying period, small hairline crack developed near the edges, and I'm not sure if this also happened within the whole piece.)

[fiddlecollector]

I think some of these makers were simply heating the wood not to a great extent but enough to colour the wood or give an aged appearance.Whether tone improvement was their motives i dont know.I havent seen any proof that Vuillaume actually did this,just hear say.But i have seen plenty of factory instruments that look to have been baked or something and ive even seen slight carborization of the wood inside.

Ive read a few interesting wood sites mainly in Finland and dealing with heat effects on construction spruce,properties such as elasticity,strength,colour,etc.. were discussed.

[Craig Tucker]

People are also freezing their wood in the electric freezer prior to use.

I'm not convinced (or vey interested) about any of these billet treatment methods, but thought I'd mention the freezing thing because a friend sent me a newspaper article about a maker somewhere in Texas that was talking about it not all that long ago. If I remember correctly, it was another "lost Strad" method, with some chain of logic tying the method to the practice.

Probably there is a great deal of violin wood that has naturally froze every winter while the tree was maturing, and then there is probably a great deal of violin wood that has frozen over the winter months while the log was either on the ground or air drying in storage.

Interesting thought.

[fiddlecollector]

Interesting idea, does the freezing expand the water in the cells and enlarge them.Therefore maybe the spruce would when made into plates be lighter and more resonant.Another crackpot thought.

I see a lot of violins on U.S ebay that appear to be treated with alsorts of things and some look very similar to some of the crackpot treatments going on in Victorian Britain.Funnily ,the ebay violins all seem to be from the Southern States such as Texas.They appear to be white chinese violins given a strange antiquing and Italian label.

[Ernst]

There is a freezing process used to treat steel but I've never heard of it being tried on wood. It's a cryogenic treatment so it's safe to say that it was not used on earlier period instruments.

It involves a slow freeze to several hundred degrees below zero F. and an equally slow thaw followed by a light warming to about 150 degrees F. The process re-aligns the molecules and eliminates inherent strain.

I tried it on two rifle barrels. My freezer (in the lab) only goes down to minus 235 F. so it wasn't really cold enough to be truly cryogenic. It worked wonders on one rifle, sifnificantly improving the accuracy. On the other there was no measurable effect. I've read that race car drivers treat their engine parts in a similar manner.

I can't imagine this process doing anything to the molecules in a piece of wood but I'd be interested to learn more about it.

[Seth_Leigh]

Cryogenic treatment of high carbon steel is done to transform austenite into martensite, which are two different forms of steel crystal or molecule, or something like that. Since tonewood is not composed of austenite, I wouldn't expect the same results.

Here's a webpage talking about that.

I have no idea what freezing to the temperatures achieved in cryogenic treatment would do to wood molecules, especially wood molecules still retaining some moisture and resins. I suppose you could always find some liquid nitrogen and immerse some tonewood in it until it's evaporated away and then make a violin out of it. I think that's what Strad must have done.