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Discussion Starter #1
What it is possible to make and whether it is possible?
How many such repair costs?
Thanks
 

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i have heard you can use water pressure to shape necks, so suppoesedly to reshape them,
not sure about price though
 

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Discussion Starter #3
SearjeantSax said:
i have heard you can use water pressure to shape necks, so suppoesedly to reshape them,
not sure about price though
I about such way never heard... How it?
 

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EddieG said:
I about such way never heard... How it?
This is from a visit to the Yamaha factory:

"The second surprise lies in the way that the curve of the neck pipe is induced without the tube kinking or flattening. The traditional method used by pipe fitters and plumbers in the UK is to insert a specially made coil-spring into the pipe, to support the tube walls and prevent it from flattening during bending. Here one sees developments of that. One is to load the brass tube with soft lead before bending. Another method is to use ice! Water us poured into the tube, then frozen. The ice supports the tube. A third method, which seems to be used for semicircular curves on brass tuning slides, is to allow the tube to flatten as it is curved. Then the tube is re-inflated with water under pressure, the tube held in a jig."

Complete visit at:
http://www.john-robert-brown.com/yamaha-at-hamamatsu.htm
 

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Using water to form complex shapes in tubular metals is called "hydroforming" and simply uses water pressure to force the metal into a preformed cavity. It is similar in it's principles to "blow moulding" in plastics which uses air and a heat softened plastic tube. It is however very expensive to tool for and really only suitable for large scale production.

Hydraulic pressure should not be attempted for this repair and would likely result in trashing the neck completey, the pressure applied will find weakest piont and distort it there, the dent is actually stronger than the surrounding metal due to work hardening and the addititional form so will resist the pressure better.

The neck is repairable but will need specialist attention to get the best result, it looks to be bent up as well as dented and may not clean up perfectly who ever does it.
 

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The neck appears to have suffered a case of "pull down" followed by trying to pull it back up. What a shame and a mess.
 

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It can be fixed with the right tools. For that area in the neck a tool can be used which is like a tapered, barrel shaped bead. It is selected from a graduated set made specifically for this pupose. It gets pulled through on a cable alone or as part of the whole set. While it is in place under the dent, the dent can be worked from the outside with small mallets and burnishers to smooth it out completely.

A curved dent rod might also be able to reach it.
 

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Keep in mind that when a neck is hydroformed by the manufacturer, the tubing "blank" is encased in a specially formed jig, to control/limit the expansion of the tube omni-dimentionally. Dent removal via this method can not be performed in a repair shop also due to the fact that no shop I am aware of has the type of extremely high water pressure capabilities in order to do so.

Relatively easy/cheap/quick repair by a tech with the right equipment.
 

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I agree with Jerry, IF that dent is actually a dent caused by impact. If it was pulled down and then someone tried to pull it back up and the result is what we see now, it could be more expensive because there will be secondary bends and stresses and twists to the metal that will need removed as well that will add time to the job.
 

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Bennyg said:
This is from a visit to the Yamaha factory:

".... Another method is to use ice! Water us poured into the tube, then frozen. The ice supports the tube..."
As I understand it, something is added to the ice so that it behaves appropriately. Sugar? detergent?... forgotten... Something simple.

BTW, instead of lead, there are bismuth alloys that melt lower than 100C, with no heat shrinkage which are used. (Rio Grande Tools sells it) Historically pitch has also been used.

However all of these are for MAKING the bent tube, not dent removal.

As Chu-Jerry says, dents like this can be removed with specialist tools... graduated pull-through dent-balls, dent-balls on rods, and judicious tapping with appropriate hammers.
 

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I have a sax neck is a bit funky too, and would be expensive to fix by reforming it. I have a sort of unrelated question, in a case thats not quite as severe as this, how will dented/damaged/deformed necks play in the real world? Does anyone have any experience with this? Can it affect intonation and response?
 

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When I had a dent in my alto neck (damn Moog Taurus pedals) and partially took it out myself you could definitely tell a difference. When I finally had the local tech take it out the rest of the way there was no difference that I could tell. Talking to the tech before and after - initially trying to decide whether to repair or replace - he said that a really good player could possibly tell the difference.

So keeping in mind that I'm not a very schooled player. Your mileage may vary. Otherwise I'm kind of proud of the battle scar on my horn.
 

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Some technicians claim to have SOLVED certain sax (intonation?) problems by inserting constrictions into the neck, at an appropriate location.

They find out how much material to insert, and where, by dragging steel shot around the inside of the neck, using a magnet on the outside.

A suitable dent in that location would have the same effect as the constriction.

So watch out technicians... You may take a dent out and get the blame for wrecking the sax that the player has got used to.
 

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Gordon (NZ) said:
As I understand it, something is added to the ice so that it behaves appropriately. Sugar? detergent?... forgotten... Something simple.
Liquid dish washing soap. I don't know why. Ed Strege told me about it and I have used it with success. I've also seen this technique in use at the Kanstul factory.
For a dent like the one shown, graduated barrel shaped dent balls, dent hammers, etc will bring it back.
 
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