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Discussion Starter · #1 ·
I seriously consider the idea of reshaping the neck of my C melody. This thread is a source of inspiration.
But I don't have any cerro bend. I find other recommendations for this purpose could be to use salt or sand. How hard would I have to stuff that filling in the neck?
Could I go out and simply borrow a little sand from the sandbox outside?
How can I be sure to not make any buckling or flattening of the neck?
Please encourage or discourage me in doing this.

Kind regards
 

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Base on your questions, I would discourage your doing this yourself, and recommend a repairman with expertise in the area. Better safe than sorry!
 

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My gut feeling is that sand is not very suitable - possibly better if it is damp.

From another forum:

"I have tried the sand method and it did not work well for me. The classic
way to make the sharp bends on trumpets and such is to fill the pipe with
melted pitch and let cool. Another method is to fill with a water-detergent
mixture and freeze it. The detergent keeps the ice from becoming hard enough
to burst the pipe. Don't ask me what the right detergent concentration might
be"
 

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What's wrong with just getting hold of some cerrobend

I have bent pipe before using sand, but you have to solder the ends closed

Pitch as used in bending trumpet pipes is great stuff, but is messy, really really messy

Never done the frozen iced water mix, so cannot comment there
 

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I recently added a 4 valve rotor to a tuba and used frozen soapy water to bend the tubing needed. It was much preferred over pitch, and I am sure my wife appreciated it not smelling as bad. I have not tried cerrobend yet but I have met some custom brass people that swear by it. I just dont bend enough tubing to get it.
 

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Just throwing this out there:

Could not a tech, using one of those neck drivers which have the gradiated balls of different diameters attached to a cable (i.e. a Ferree's P58 ~ http://www.ferreestools.com/brasswindtools/brasswind-dentcabledrivers.html), bend a neck at the desired point by simply fitting in the proper sized ball at the proper location ?

This would prevent the neck tube from 'ovalizing' during the bend.

Or am I being too simplistic, here ???
 

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The ball would be squeezed out of position during the bend
 

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But given the steel ball is stronger than the brass pipe, and the ball would be held in it's location by the driver , would not the ball remain stationary, and the pipe therefore conform to it ?
 

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No, because the pipe is supported at the ball location but at the other locations between the balls as they are a tapered ball they are unsupported, the unsupported areas will give way and crease, as the neck wall gives way over these areas the ball is pushed forward or backward accordingly, but you still end up with a creased area.

To this end, even if it did work it would be too costly, you would need a set of sized balls to be capable of being threaded, allied votaw and ferees sell these for about 1000 plus dollars for the 5" incremental set and 2000 dollars plus for the 2" incremental set, you would also need a neck driver to suit, these are also available from these companies and I think they cost a couple of hundred for alto and same again for tenor sax's, I cant remember the prices as I bought my stuff quite some time ago now, but had a small fit inside when I paid for them

Not to sure if most people realise but when you start getting into the more serious repairs that require specialised tooling, the price is obscene, there are far easier and less expensive ways toi make a buck, electrician, jet mechanic, maintenance facility for a space shuttle :bluewink2:, pretty sure these would have less overheads than instrument repair
 

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Some will remember that I carried out a similar neck bend on my Martin Typewriter some years ago.
My comments & "before & after" photographs are somewhere on, I believe, the C Mel section of the forum.
I am not a plumber, but the operation was a complete success.
Cerrobend, liquid at water's boiling point, is essential.....someone on this forum was kind enough to sell me a small quantity. I would not have attempted the job with wet-sand packing.....that's best left to the ship building industry.
Probably not a job for the faint hearted or totally unskilled (or accountants/estate agents)....but, carefully thought out, & taking one's time, it should not be too difficult
for anyone with average handiwork skills......and a Black & Decker "Workmate".
 

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Use good ventilation and appropriate caution:

"Cerrobend is an alloy of bismuth, lead, tin and cadmium..."


Sent from my iPad using Tapatalk
 

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Captain B....is this the method you used (scroll down to 5th paragraph) more or less ? And did you just let it run over the octave pip ?

http://www.hitechalloys.com/hitechalloys_005.htm

Also, the stuff doesn't seem very pricey, particularly if it can be re-used:

http://www.ebay.com/sch/i.html?_fro...A0.H0.Xcerrobend.TRS0&_nkw=cerrobend&_sacat=0
With no previous experience....just common sense & handicapped by two engineering degrees, this is the method I used.
Henning 1 contacted me by PM, & I feel certain that he would not mind me publishing here my reply to him:-

Hello Henning1.
I am assuming that you are reasonably good with your hands.....this is possibly not the job for a typical accountant.
To answer your questions briefly in order:-
1/ I half filled the neck....enough to accommodate the area to be bent.
2/ Cerrobend can be re-used indefinitely.
3/ Yes...heat to remove the Cerrobend....explanation following.
4/ No subsequent trouble whatsoever.
Method....
Make a former of the desired radius.....I used a short length of plastic guttering downpipe....I strengthened it by cutting off several short pieces of the same pipe & cut a lengthways gap so that when the edges were squeezed together they fitted, progressively inside the short outer length to effectively increase the wall thickness, & thereby strengthen the outer former....ie. to prevent it flattening when the neck was bent around it.
I found a metal coffee jug of a size where the neck could stand almost upright with the tenon end upermost & into which I could pour the molten Cerrobend.
Fitted a cork into the mouthpiece end (to prevent the Cerrobend from flowing out) & filled the jug with water. Drop in the neck....small end down & the tenon end accessible for pouring the Cerrobend. Bring the water to the boil.....this, of course, to prevent the Cerrobend from instantly hardening as it would if the neck were cold.
At the same time, put the solid Cerrobend pellets into a suitable container into a saucepan containing a small amount of water....so that the top of the Cerrobend container is above water level (obviously).
Cerrobent liquefies just below the temperature of boiling water.
Boil the water in the saucepan until all the Cerrobeny has turned to liquid...& using tongs or pliers lift out the Container of liquid Cerrobend & pour into the tenon end of the neck to a point where it is well above the area to be bent.
ALLOW THE JUG, STILL CONTAINING THE NECK TO COOL DOWN SLOWLY.
This is vital...because if you cool it quickly the Cerrobend will expand in all directions & split the neck seam.
Cooled slowly, the cooling Cerrobend will take the line of least resistance & naturally expand harmlessly up the neck.
When cool....even if this takes an hour or two, you are ready to bend the neck...&, thanks to the presence of the Cerrobend, it will not flatten to any degree.
To actually bend it I used a "Workmate"......one of those folding work-stands with the two sections of the top acting as a vice....I am sure that you know what I mean & that you have one in your garage.
I opened the jaws of the vice to hold the home made former in position with the neck placed in position horizontally between the former & the edge of the vice & gently tightened....in a position such that the neck would be firmly held when the bending force was applied. Movement of the open end of the tenon was restricted by the fact that it rested against the othe side if the vice.
With the mouthpiece end of the neck protruding from one end of the vice I wrapped it with masking tape to the inner diameter of a metal tube which I slid over the masked (& thereby protected) end of the mouthpiece....& pulled the neck around the trapped former. You will require the extension tube to apply the necessary force. Also have someone available to hold the Workmate....it will obviously try to rotate against the force. I actually jammed it against a wall to prevent the torque reaction....it requires quite a force to bend.
Finally, when bent to a suitable degree...remove the cork from the mouthpiece end & stand the neck once again in the jug of boiling water....obviously lifting it a bit to allow the melting Cerrobend to escape from the end.

Note.
Writing all this down makes it sound far more difficult than it is in practice.
Please email me if anything I have written is unclear.
The upward bent makes a HUGE difference to the playing comfort.

All the best, Lewis.

JayePDX.
You are correct in assuming that the octave pip was a concern.
In avoiding it, I seem to remember that all the bend had to, & was achieved, over one inch of the neck's length.
 

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Thanks for that. Interestingly.....your method seems to slightly contradict the link which I found. Not being judgmental or a doubting thomas in any way, just saying.

Your method suggests a slow cool of the liquified cerrobend in the neck....while my link suggests a rapid quench:

"Cerrobend conforms snugly to the inside of the tube that the tube can be bent as though it were a solid bar. This quality is due to the fact that Cerrobend expands slightly instead of contracting on solidification.
Molten Cerrobend normally cools and crystallizes slowly, resulting in a coarse crystal structure and is quite brittle in this condition. However, if it is rapidly chilled, it acquires a fine-grained structure that renders it very ductile.

The molten Cerrobend is poured into the tube, displacing any residual oil. It is better to hold the tube at a slight angle when filling and allow the metal to flow down the inside wall of the tube. This will help prevent air gaps. Once the tube is full of molten alloy, it is plunged quickly, corked end first, into a tank of cold water about 50º F. This insures a fine crystalline structure in the alloy, which makes it ductile and easy to bend".

When you cooled it slowly, was the result "a coarse structure quite brittle" in any way ? Or did it seem your cooled Cerrobend was flexible/ductile ????

This is a very interesting process, I am sorta diggin' it.....
 

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Realising that water expands on freezing I was not prepared to take any chances with a valuable neck.
Consequently, prior to working on the neck, I filled an aluminium cigar tube with molten Cerrobend, screwed on the cap, & plunged it into cold water.
The tube split.

Enough reason for me to cool the Cerrobend in the neck slowly.

Depends to some degree of their definition of "snug fit".....I saw that a "snug fit" was rather too snug to risk on a thin wall tube with a seam. :bluewink:
 

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A little bit off topic, but will this new bend affect the intonation at all? resistance?
 
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