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 Cementing a broken upper joint
Author: saxlite 
Date:   2005-12-01 01:39

I have a Plastic Vito with the upper joint completely broken in half through the thumb hole. It's a clean break, no small bits. Looks like a total loss unless I can find a suitable cement to glue the two pieces together. Anybody know of a suitable glue?



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 Re: Cementing a broken upper joint
Author: ron b 
Date:   2005-12-01 04:25

First of all, Saxlite, before you do anything, you'll need to find a way to hold the two pieces together tightly so they won't move at all. Maybe your tech friend will loan you a tone hole jig or something like that to hold it together, totally immobile while it "mends". I made a jig out of threaded rod (hardware store), nuts and washers.

There are many ways to approach this type of repair, all of them good. Some are a little better than others. You'll need to pick one that suits your circumstances and available materials and equipment.

Ferree's recommends Jet Magic and it does a good job, from what I'm told. I've also used black epoxy with good results. In any case, whatever you decide to use, don't let those pieces move until everything is set and cured properly. Do your cosmetic clean-up after the repair process is done.

Acrylic Cement (from Tap's Plastic) has worked very well for me on several Bundy plastic horns. It's a very thin runny liquid adhesive -- runs like water. Available locally right away, so you don't have to wait for shipping time. With the pieces snugged tightly, you apply a drop or two of cement to the crack. The thin cement will "flash" through the cracked area almost instantly. A [verrrry] little goes a long way so, *don't over-do it*.

If you can take the broken pieces to the plastic store, they might be able to tell you right away which cement to use. I've never done a Vito. The plastic may be a different variety than Bundys.

Our friend, Gordon, uses pins as a re-enforcement measure on tenon repairs. Maybe he'll find time to respond to this thread.


- r[cool]n b -

p.s. -- I forgot to mention that alcohol is NOT RECOMMENDED for cleaning plastic. Use mild detergent and warm water to clean the surfaces before gluing. Alcohol, we're told, will to bad things to the molecular structure of some plastics. It's best not to 'chance it'.



Post Edited (2005-12-01 04:30)

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 Re: Cementing a broken upper joint
Author: Gordon (NZ) 
Date:   2005-12-01 11:04

As Ron indicates, technicians have used a range of glues, mostly of the superglue type or of the solvent-for-abs-plastic type.

Be aware that there are many types of superglues (cyanoacrylate) and while some may work well, others will be useless. Some technicians claim that the result can be stronger than the original material.

I have some reservations, having seen SO many glue failures in all sorts of applications, especially other superglue. Many glue joints wait for a while to mature before they fail. Superglue eventually sets very brittle. I think it is likely to succeed only if it has a solvent action on the plastic and actually welds it together.

So to be certain, I developed my own method of inserting 6 or 7 hidden stainless steel rods, about 1.2 mm diameter and 40 mm long, surrounded with epoxy cement, in 1.4 mm diameter lengthwise holes in the body wall.

An advantage of this is that the glue around the pins is stresses in SHEAR, where adhesives are typically much stronger. I have been able to guarantee the result, and after perhaps over 60 of these, I have never known of a failure. Indeed, many of the joints I have done in this way were tenons, and I have had a few instruments come back with broken tenon sockets, next time those instruments were sat on, testifying to the reliability of this method.

Of course it takes somewhat longer - perhaps 60-80 minutes for me, and is therefore more expensive. It is the detail that makes this a complicated job to do with a reliable result, especially in the middle of a body, so it is really outside the scope of the home handyman.

Perhaps some day I will trust butt-joint glue on its own. :-)

It is interesting that this instrument is a Vito. It is reasonably common for a Vito to break, and this is one of the advantages I have found in Yamaha.

It is also interesting that the break is at the thumb ring. I once encountered a run of several instruments of the same make that all broke here. They were either Armstrong or Artley. They must have been a faulty batch from the factory. My theory is that the thumb tone hole insert was jammed into too small a hole, such that the plastic was highly stressed in the vicinity. Then in cold weather, when the plastic shrinks more than the metal, the stress would be even greater. Then just a little extra force, say during assembly, and the body broke.

Sometimes technicians may get a replacement half body, but often it can be a major job re-fitting the keys to a replacement body, when the model does not have sufficiently standardised spacing between posts. Some keys need shortening and some need lengthening. Repadding may well be necessary too, so it can grow to quite an expensive job.

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 Re: Cementing a broken upper joint
Author: David Spiegelthal 2017
Date:   2005-12-01 14:36

I've independently come to the same conclusions as Gordon -- the only truly reliable repair of broken joints is to use the proper adhesive (usually a filled epoxy or plastic-specific acrylic-type glue) PLUS metal reinforcing pins. I just repaired a broken Vito bass clarinet center joint tenon in exactly that manner.

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 Re: Cementing a broken upper joint
Author: BobD 
Date:   2005-12-01 15:39

Yes, thanks Gordon and Dave for you always good analyses. "Yes, Virginia, plastic will crack." My opinion would be that a clean circumferential crack in a Vito top joint at the thumb hole would be a job for an expert like Gordon. I'm still "sitting on" and watching two Vitos that I repaired with filled epoxy but they were in tenon areas and not "clean" fractures. A thumbhole failure could be the result of a "cold shut" during molding (as well as Gordon's thought) and if so will be a zone of weakness that even a satisfactiory crack repair might not remedy. Prognosis negative.

Bob Draznik

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 Re: Cementing a broken upper joint
Author: Chris P 
Date:   2005-12-01 17:01

As well as glueing the fracture and pinning, has anyone milled slots into the body across the fracture and secured the two parts with several metal plates around the outside wherever possible, all screwed into the slot, then the slot filled flush with the surface to cover the plates so the repair is hidden?

Similar to how some fractures in bones are fixed with metal plates.

Probably a bit excessive on some plastic instruments as a replacement joint would be more economical, but just a thought.

Chris.

Post Edited (2005-12-01 17:02)

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 Re: Cementing a broken upper joint
Author: tictactux 2017
Date:   2005-12-01 17:12

Why cover the plates? Would make a nice Halloween instrument. ;)

--
Ben

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 Re: Cementing a broken upper joint
Author: Chris P 
Date:   2005-12-01 17:34

HAHAHA!

I've seen a plastic Vito bass clarinet with a DIY middle socket repair (the ring snapped off taking tke socket with it) - it just had a Jubilee clip around it holding everything tight!

Looked bloody ugly but it worked, and it's still going!

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 Re: Cementing a broken upper joint
Author: David Spiegelthal 2017
Date:   2005-12-01 17:37

I've worked on a few bass clarinets in which a previous technician had reinforced a center joint repair with recessed plates that spanned the joint and were screwed in place with three screws on each side. Typically three such plates were installed per instrument. It's a very good fix mechanically, but the plates are quite visible (no big deal) and of course their presence eliminates the possibility of disassembling the two large joints routinely (except for maintenance). It's also a lot of work to make the recesses in the body for the splice plates. This type of fix would be very tough to implement on the usual "Vito bass clarinet break" where the fracture occurs at the sharp juncture of the upper joint's lower tenon, and the upper joint body.

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 Re: Cementing a broken upper joint
Author: saxlite 
Date:   2005-12-04 04:14

Thanks, guys. Tap Plastics had a very nice acrylic cement- Weldon #16-- this comes in a toothpaste-tube and is reasonably viscous; they also had a really neat little applicator for 40 cents. After cleaning all surfaces with alcohol, I coated both surfaces with a thin coating of the cement and clamped it with the threaded rod scheme as suggested by ron b. I let it sit for 36 hours, then tried to break it--it held just fine. Finished it up, tested it for leaks, and lo and behold -- it plays like new! Since this was an inexpensive used school horn, I elected not to use Gordon's pinning scheme. We'll see how well it holds up.
Thanks for all your good suggestions!
Jerry



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 Re: Cementing a broken upper joint
Author: Don Berger 
Date:   2005-12-04 13:30

A friend's daughter broke her lower U J tenon, about half-way, on a Vito [no-name], prob. Resonite Bb. I strongly suggested getting a used replacement joint from my GOOD repairer in Tulsa, but did try to Superglue it [low viscosity SG]. So far it has apparently held up, I did give quite a lecture on horn care, and made sure the corking was barely tighter than the "falling off" stage. I do expect to hear before too long. ?Fun??, Don

Thanx, Mark, Don

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 Re: Cementing a broken upper joint
Author: stumusic 
Date:   2018-01-27 17:11
Attachment:  16BCF4B7-545A-4AD7-A0E8-890AC0BB3F5A.jpeg (1747k)

Hi Gordon. I recently got an unpleasant surprise when a Vito Eb clarinet I bought on eBay arrived with a crack running from a post to the thimb hole. The seller insists they are not responsible and will not take it back so I need yo make the best of it. The instrument is not leaking and plays well. I hear the “ ring of truth” in your suggestion that a tight thumb hole insert might have contributed to this crack. The question is, do I try and use pins or a clamp to draw the crack together after filling with glue, or just fill the crack? My gut says just fill it as the crack may have resulted from tension that has been rekeased. Clamping or pinning may reintroduce the same tension that caused tge crack. Thoughts?

Stuart Holmes
Instrumental Music Director
Wangenheim Middle School
San Diego, CA 92126

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 Re: Cementing a broken upper joint
Author: Hank Lehrer 2017
Date:   2018-01-27 19:06

Stuart,

You need to file a complaint with eBay that the instrument you bought had a crack that was not disclosed in the initial description for the item. Perhaps first tell the seller what you plan to do and see if that brings about a refund.

HRL

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 Re: Cementing a broken upper joint
Author: stumusic 
Date:   2018-01-27 20:01

Thanks Hank. We are in eBay’s “three days to work it out” period, but yes, I’ve contacted them. I think the seller initially made an honest mistake, but should take it back. Their contention is that they posted ample pictures, it wasn’t cracked when they sent it, and they are sorry for my loss. Not a hopeful reply. Their pictures were not of sufficient quality or close up enough to have shown this crack. I even suggested I’d give the benefit of the doubt and settle for the estimated cost to repair. In the mean time, I’m just researching my best repair option. Some of the comments here about Vito vs. Yamaha are interesting because for many years I managed a music store and both Yamaha and LeBlanc told me up until the 90’s Vitos were made by Yamaha. (Of course I’m not sure of the vibtage of this particular Vito.)

Stuart Holmes
Instrumental Music Director
Wangenheim Middle School
San Diego, CA 92126

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 Re: Cementing a broken upper joint
Author: Tony F 
Date:   2018-01-27 20:22

Looking at the crack, it may have been caused by a side load or knock on the post, such as might happen during handling. If you can't get a resolution through EBay I'd probably look at just gluing. Not knowing what the material is I'm not sure as to what the best agent would be. Superglue doesn't work well on some materials.
I'm assuming that this is a plastic instrument, and if that is the case I'd take a shaving of the material from somewhere inconspicuous and see what reacted with it. On an old cracked plastic instrument I once had good results using Methyl Ethyl Ketone (MEK), but be aware that this stuff is extremely toxic until it evaporates.
If the plastic of your instrument reacts then it may provide a good bond. It works by melting the adjacent surfaces into each other, so apply it carefully with a toothpick directly into the crack. If it was a knock on the post it may have affected the end float of the thumb ring hinge tube.

Tony F.

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 Re: Cementing a broken upper joint
Author: Steven Ocone 2017
Date:   2018-01-27 22:38

I would carefully flex the instrument and see if the crack continues on the opposite side of the tone hole or elsewhere. If the crack in the photo was the only issue I would have it sealed with a good super glue. With a crack like I see in the photo, the clarinet would not be sealing to my standards.

Steven Ocone
Ann & Steve's Music

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 Re: Cementing a broken upper joint
Author: Bob Bernardo 
Date:   2018-01-28 04:09

Be careful with epoxy. Epoxy is not a cement or a glue. It is actually a type of plastic and it comes in many forms, probably 1000 different types are made. some dry fast, some shrink too much. you get the idea, some won't work on horns.

I've never fixed one so I won't offer any advice.


NEWLY DESIGNED - Vintage 1940 Cicero Mouthpieces


Yamaha Artist




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