Bridge treatment - what is the purpose?

[Norby]

Hello all,

 

Some bridge makers claim their bridges have been treated (whilst untreated bridges are also available). Could you tell me what is the purpose of treatment and what chemicals do they use? Do they treat the wood just because of darker look, or because of sound quality?

 

Thanks!

[Marty Kasprzyk]

Good question!  My guess is that it is just a marketing-advertising gimmick for claiming their bridges are better than anybody else.

 

I've treated some of my bridges with coffee to color them but also got a brighter sound especially in the morning.

[ctanzio]

I've treated some of my bridges with coffee to color them but also got a brighter sound especially in the morning.

 

Everything sounds dark and moody to me in the morning. But once I treat myself with some coffee, tones dramatically brighten. MN needs more threads on chemical enhancement of the player rather than the violin, IMNSHO.

[DGV]

Wear earplugs for 2 hours.  Then play your dark violin.  It will sound unbearably bright.

[Norby]

Somebody told me that they treat the wood in order to make it harder or stronger.

 

I am not sure it is necessary. I assume that the main job of the bridge should be transferring some frequencies whilst damping others at least partially. Otherwise the design of the bridge would be not so intensively carved. Below the kidneys there is a horizontal bar working as a spring in fact. If the stiffness would be the priority and the carved parts should be applied just for weight reducing, the ideal design of the bridge would be different I am pretty sure.

 

Am I wrong?

[duane88]

Ammonia, I think.

 

You can treat your own;) Just drink enough coffee!

[Will L]

If you're talking bridge blanks, I have no opinion, but people I trust do and they avoid intentionally very darkened blanks.

 

But a recently worked bridge can be garish, and a little darkening helps.  It can be done even with a little schmutz from the bench and rubbing with the fingers.  Roy suggests rubbing the bridge into a carpet loaded with ocher and black pigments.  

 

I think the main idea is not to put anything into the wood which would go too deep or change its nature.  I've used very thin shellac/alcohol with a drop of linseed as in French polishing.  I like that look, but don't know if it's horrible to anyone for some reason.

[Violadamore]

As has been noted before, perhaps most memorably in Roger's bass thread, bridge makers treat them with ammonia from various sources to harden them, which should make them springier.  It also gives you an excuse to take your rabbit raising expenses as a tax deduction.   

[Don Noon]

To my knowledge, there is no report showing how maple properties change with ammonia treatment.   Perhaps that is an indication of something (or rather, nothing).

I tried ammonia, with nothing significant to report, other than it got darker.  I measured some ammonia treated wood from others (spruce) that didn't display any outstanding properties.

 

At the last VSA, there was a presentation of a soaking method for treating maple for bridges (supposedly a Milo Stamm process).  The results were less than fabulous:  a slight weight loss, but no change in speed of sound.

 

I thermal treat my bridges for color and perhaps warp resistance, but otherwise they sound just like any other bridge to me.

[kyproset]

I can only offer my opinion as a player regarding bridges.

 

I own a J.B.Vuillaume violin that has been maintained by the same excellent luthier in all the years in my possession.
In the early 1990's we were using  good quality Aubert bridges like everyone else. Some of them old and in the possession of my luthier from some retired source.

When the Milo Stamm bridges came out, I had one cut for the Vuillaume and the improvement in the sound was amazing.

The luthier said that while cutting it, it felt crispier under the knife, also denser. When we were choosing the one to use among many, we were dropping them on a flat table from a little distance to establish the ring. In all attempts,all the Stamm bridges were ringing at a higher pitch than any of the Auberts we tested. I had one cut for my modern violin as well with the same improved results.

In my humble opinion as a professional player these treated Milo Stamm bridges do offer considerable sonic advantages.

 

I'd like to ask a question while on the subject of bridges to all you professional luthiers.

What is the effect of opening up the kidneys on a bridge?

If the G string kidney is enlarged, in which direction would the sound be affected?  Will this affect the G string alone or all the rest of the strings and what is the effect of opening up the E string kidney?

Thank you.

[jim mcavoy]

When the Milo Stamm bridges came out, I had one cut for the Vuillaume and the improvement in the sound was amazing.

The luthier said that while cutting it, it felt crispier under the knife, also denser. When we were choosing the one to use among many, we were dropping them on a flat table from a little distance to establish the ring. In all attempts,all the Stamm bridges were ringing at a higher pitch than any of the Auberts we tested. I had one cut for my modern violin as well with the same improved results.

In my humble opinion as a professional player these treated Milo Stamm bridges do offer considerable sonic advantages.

 

If you put a bridge in the oven at 190 F for an hour the bridge will darken (a little) and ring higher  I can't speak to Stamm bridges, but the result is that I have tempered the (cheap) bridge and the ring comes out quite a bit higher, and would say that under the knife it is 'crisper'.  (a new term for me) No pun intended

 

For what it is worth

Jim

[Don Noon]

If you heat wood it will lose moisture (and weight) very quickly, and re-absorb moisture from the air very slowly.  To see what changes have really happened, you need to test periodically in a fairly constant RH atmosphere, and see when it stabilizes.  Heating to 190F for an hour I don't believe would make much of a permanent change in the wood, if you compare before and after in stabilized EMC conditions.

 

IMHO, for mechanical properties, the selection of the wood far, far outweighs whatever treatments you do to it, since wood varies a lot, and treatment doesn't do much, if anything.  Unless you do something radical like 450F for several hours, then you have charcoal... but it won't make a good bridge.

[David Beard]

I believe there is along history of ammonia fuming woods in general woodworking traditions like furniture making etc., but for cosmetic purpose.

 

It seems fair to suspect that fuming bridges might have begun for cosmetic reasons, and could easily have continued for cosmetic and marketing reasons alone.  

[jim mcavoy]

If you heat wood it will lose moisture (and weight) very quickly, and re-absorb moisture from the air very slowly.  To see what changes have really happened, you need to test periodically in a fairly constant RH atmosphere, and see when it stabilizes.  Heating to 190F for an hour I don't believe would make much of a permanent change in the wood, if you compare before and after in stabilized EMC conditions.

 

IMHO, for mechanical properties, the selection of the wood far, far outweighs whatever treatments you do to it, since wood varies a lot, and treatment doesn't do much, if anything.  Unless you do something radical like 450F for several hours, then you have charcoal... but it won't make a good bridge.

Don,

You may well be right so I will keep an eye on the subject bridge.  It started at an E flat and went up to an A ( 6 semitones ) if it goes back to an E flat then I'm all wet......Still no pun intended

 

I chose 190 because that is the core temprature for putting an arch in a bow ....or so I am lead to believe. It was in the oven for as long as it took to bring out a small load of winter wood. I did the final tone observation about 12 hours later ..It just set out, in the air, on the keyboard, on the two black keys  (closest to middle C)

 

Jim

[nathan slobodkin]

If you heat wood it will lose moisture (and weight) very quickly, and re-absorb moisture from the air very slowly.  To see what changes have really happened, you need to test periodically in a fairly constant RH atmosphere, and see when it stabilizes.  Heating to 190F for an hour I don't believe would make much of a permanent change in the wood, if you compare before and after in stabilized EMC conditions.

 

IMHO, for mechanical properties, the selection of the wood far, far outweighs whatever treatments you do to it, since wood varies a lot, and treatment doesn't do much, if anything.  Unless you do something radical like 450F for several hours, then you have charcoal... but it won't make a good bridge.

Don

I have seen makers heat treat bridges by toasting them to a too hot to hold level for about five minutes on the theory that they will be more resistant to bending. Also was taught when making a bow to avoid reheating a stick without letting it cool between heatings because it would take a set and be difficult to bend any further. Are these just old fiddle maker tales? I know that my bridges seem to last quite well but then again I try to hang them up for at least five years before use. Is it possible that chemical changes are occurring in the wood that are not simply MC variations? I surely beleive that wood continues to season long after the MC has reached equilibrium.

[jim mcavoy]

re: the oven heated subject bridge

a day later and it seems to be holding at the A natural

what has changed is the weather today the temp is 52 and the RH is 91 ((cold and clammy) when I started this, it hot and dry (RH about 30) .... I don't think this bridge will return to the E flat that it was at the outset .... but we will wait and see

 

Don, could you predict a time frame for these observations ...I will be turning 75 soon, and I don't want to leave things half done. In my family, people tend to croak some time after 80 years old (some in their mid 90s)

 

Jim

[Don Noon]

Nathan, 

 

Temperature matters a lot.  I have tried lowering the temperature for my thermal processing, and have found that not much happens below ~250F, other than driving out moisture.  Certainly I would not expect anything at 190F.  For rib bending, I use about as hot as possible without scorching the wood, which seems to be just over 200C, or about 400F.  Things happen rapidly at that temperature, although I have not actually measured changes quantitatively.  Anyone who bends ribs knows that, though, and I presume bow making is similar.  I don't know what is going on with heating and cooling vs. bending all at once, so I can't judge if it's a tale or truth.

 

As for wood seasoning, I don't have data on that, only theory, which suggests that the type of changes I can measure from thermal processing should also happen at ambient temperatures, but over a very long time.

 

Jim,

Probably a few weeks for a bridge, which is pretty thin.  For plate wedges, I usually see the curves flattening out about 3 months after thermal processing.

[Melvin Goldsmith]

I'd always prefer very good wood before and regardless of 'treated' or untreated. These days there is too much concentration by bridge makers on the decotartive  medullary rays.This throws lots of crappy wood into the mix that can get top grade. The best proven old bridges I know do not excell in this aspect but certainly do have very tight growth. That is what I look for first. Treated or not it should be very easy for an experienced luthier to pop whatever color they want on a bridge.

[nathan slobodkin]

I'd always prefer very good wood before and regardless of 'treated' or untreated. These days there is too much concentration by bridge makers on the decotartive  medullary rays.This throws lots of crappy wood into the mix that can get top grade. The best proven old bridges I know do not excell in this aspect but certainly do have very tight growth. That is what I look for first. Treated or not it should be very easy for an experienced luthier to pop whatever color they want on a bridge.

Absolutely true!

[Norby]

Kyproset - accoring my experience, the kidneys size as well as heart size affect the total weight of the bridge. This is why larger kidneys make the sound louder, but if you make them too large, (and therefore the bridge too light) the response and playability may be affected in a negative way. The violin might become less forgiving.

 

I think the less projecting violin the lighter bridge can be applied, but one needs to be cautious with bright and well projecting instruments. 

Edited June 2, 2015 by Norby

[uncle duke]

I can only offer my opinion as a player regarding bridges.

 

I own a J.B.Vuillaume violin that has been maintained by the same excellent luthier in all the years in my possession.

In the early 1990's we were using  good quality Aubert bridges like everyone else. Some of them old and in the possession of my luthier from some retired source.

When the Milo Stamm bridges came out, I had one cut for the Vuillaume and the improvement in the sound was amazing.

The luthier said that while cutting it, it felt crispier under the knife, also denser. When we were choosing the one to use among many, we were dropping them on a flat table from a little distance to establish the ring. In all attempts,all the Stamm bridges were ringing at a higher pitch than any of the Auberts we tested. I had one cut for my modern violin as well with the same improved results.

In my humble opinion as a professional player these treated Milo Stamm bridges do offer considerable sonic advantages.

 

I'd like to ask a question while on the subject of bridges to all you professional luthiers.

What is the effect of opening up the kidneys on a bridge?

If the G string kidney is enlarged, in which direction would the sound be affected?  Will this affect the G string alone or all the rest of the strings and what is the effect of opening up the E string kidney?

Thank you.

I'm not a professonal Kyproset but I have made a few bridges from scratch.  About opening the g side and e side kidneys-   The change is minimal or barely noticable.  Between the kidneys is a 15.5mm distance.  If it's wider you could remove wood.  I look at the outer kidney area as a filter or damper.  If you remove wood in the outer kidney the vibration {if any} will go elsewhere, hopefully down to the feet.  Long story short-  the outer chamferings and overall thickness of the bridge from feet to top will be more noticeable if wood is removed as compared to kidney wood removal.  Some violins need more wood and others will work with less wood thickness-wise for bridges,

[Marty Kasprzyk]

Good question!  My guess is that it is just a marketing-advertising gimmick for claiming their bridges are better than anybody else.

 

I've treated some of my bridges with coffee to color them but also got a brighter sound especially in the morning.

I forgot to mention that I've also treated my new bridges with natural vanilla extract to give them a light tan color in an attempt to make them visually attractive.  If lightly done, the smell also gives a favorable subliminal soothing effect to the sense of smell.

 

 I also very carefully polish  the neck and all the instrument's edges to give another soothing effect to the player's sense of touch.

 

If the instrument looks good, smells good, and feels good maybe it doesn't have to sound good.

[Lusitano]

I can only offer my opinion as a player regarding bridges.

 

I own a J.B.Vuillaume violin that has been maintained by the same excellent luthier in all the years in my possession.

In the early 1990's we were using  good quality Aubert bridges like everyone else. Some of them old and in the possession of my luthier from some retired source.

When the Milo Stamm bridges came out, I had one cut for the Vuillaume and the improvement in the sound was amazing.

The luthier said that while cutting it, it felt crispier under the knife, also denser. When we were choosing the one to use among many, we were dropping them on a flat table from a little distance to establish the ring. In all attempts,all the Stamm bridges were ringing at a higher pitch than any of the Auberts we tested. I had one cut for my modern violin as well with the same improved results.

In my humble opinion as a professional player these treated Milo Stamm bridges do offer considerable sonic advantages.

 

I'd like to ask a question while on the subject of bridges to all you professional luthiers.

What is the effect of opening up the kidneys on a bridge?

If the G string kidney is enlarged, in which direction would the sound be affected?  Will this affect the G string alone or all the rest of the strings and what is the effect of opening up the E string kidney?

Thank you.

 

Not to go against your findings (I actually agree!) but each blank is different even when bought from the same company with the same grade and from (supposedly) the same tree. How do i know this? I've had 2 Aubert bridges carved for the same violin in the exact same manner (clones of one another) and one was a hell of alot "better" sounding than another. My current violin has had 3 bridges installed (1 despiau, one Aubert and one milo Stamm), without a shadow of a doubt I can say the following.

 

1- Despiau (treated, I believe n 11) produced an extremely focus sound which was exceptionally aggressive in nature, massively responsive and impossibly loud in a sort of pleasant way as the volume had character. Projection was good (but then again the violin itself is on the powerful side). Sadly the violin was far too focused and did not play well with others, all strings sounded dark (and evahs managed to make the violin sound furious which was actually pretty interesting lol ).

 

2- Aubert (Deluxe) produced a hell of alot more color than despiau with a change in tonal character that made the violin sound alot less focused but much warmer and more evan. Responsiveness was still very very good with the curious benefit of having the G and D strings (even in first position) powerful still  but majestic. Oddly, it seemed to project more and with a lot more sustain and color on harmonics and general "rings" than when the despiau bridge was on. Basically, it made my violin go from mono to surround sound lol

 

3- Milo Stamm - When compared with Aubert it was less "round" sounding but had a lot more (although entirely different ) ring and color. It's no where near as harsh (focused) as despiau but not as round sounding and forgiving as Aubert. It seems to now have more projection and it's very obviously overflowing with overtones I could not get when the aubert bridge was on.  Basically went from surround sound to Dolby HQ surround sound

 

My favorite so far? Milo stamm by a very small margin when compared with aubert! Aubert "looks" better than milo stamm real Ponticeli and has a very warm and pleasant sound while being friendly and gentle but the Real Ponticeli manages to simply produce a much vaster color palette with a bit more edge which allows me more options when playing. 

 

I should mention that the Despiau was made from a "new" blank and that the Aubert was one of the "old" blanks the luthier had. 

 

I forgot to mention that I've also treated my new bridges with natural vanilla extract to give them a light tan color in an attempt to make them visually attractive.  If lightly done, the smell also gives a favorable subliminal soothing effect to the sense of smell.

 

 I also very carefully polish  the neck and all the instrument's edges to give another soothing effect to the player's sense of touch.

 

If the instrument looks good, smells good, and feels good maybe it doesn't have to sound good.

 

I like you... If only all luthiers where as mindful as you are, I've had more than a few violins come back smelling of pure evil (I'm being nice with the use of the word evil) all because the folks who worked on the boxes of wood had no regard for how offensive the smell of some of their products are... Raw linseed oil on fingerboards which oxidizes  and smells like the devil himself for ages when they could have used lemon oil... Bridges with a distinct smell of ammonia (piss) because they were "treated" to make them darker, peg dope heated up and placed on the pegs themselves that ended up smelling like burnt rubber....

[jim mcavoy]

re: subject bridge

2 days down and still rings at A natural

 

This is a drop test which is a little tricky.. the bridge has a taper which will render more that one ring (as will a tapered bow) but is easy to do and is in keeping with kyproset's posting of 30 May

 

Obviously my interest is up.... so at the end of two weeks I will fit it on a violin, along with a companion bridge (not baked), which I am using as a control

 

There is nothing special about this 'no name' bridge,  they are from a bulk purchase and are cheap ....about 50 cents each and I have no idea how all this will pan out. They have been sitting in a small drawer (along with some caulk) to stabilize for about two years.. and had no immediate use for them planed

 

Jim

[Ben Hebbert]

Somewhat regrettably, I think that a darkened bridge is just a bit of presentation that counts for much and gives the instrument a look of being attended to in every possible way. It goes along with polishing the shanks of the pegs, and those other tiny elements of presentation. It contrasts against the rushed bridge, which normally has no colour, and as others have said earlier - can - look cheap. 

 

I wish I had a clever and less mysterious answer!