tárogató Remanufactured Part Deux

I got my new "toy" in the mail today. It is the Celestron #44302-A Deluxe handheld digital microscope.

It will be used to help in the refinishing of the tone holes on the tárogató. In spite of its low cost, it give quite clear images and photos under magnification. Here are a few examples of the tone holes on the upper joint that will need some work.

It will save a great deal of time if I can find some of Ferrees clarinet tonehole cutters close enough to the sizes of the tone holes on the tarogate to make work. For those tone holes without a cutter to match, I will have to make or devise something that would work. Having cutters custom made for this one project would probably be cost prohibitive.

 

Luckily I have some good tools (borrowed) and the Martin Freres clarinet upper joint to practice cutting the new tone holes on. Getting adept at building up the wood with CA glue and grenadilla dust will take some practice as well. I need to buy some fresh CA glue in various viscosities to see which type is the easiest to work with.

 

What's the shelf life on those? Exactly year ago I bought Loctite 406 on amazon (I read about it as being one of the toughest superglues and recommended for fixing clarinet cracks) and I've been using it since with good results. I hope it's still good - I need to build up the inside of upper joint mouthpiece tenon (separate post on this forum). I'll be using ebony dust.

George

 

In my experience the "shelf life" is quite good for the B.S. (Bob Smith Industries) brand of CA I buy. However, once a bottle has been opened, the product tends to thicken after being exposed to air after a period of time---especially when people like me forget to replace the cap.

I'm going to experiment with CA glues of different viscosities with and without the accelerator combined with grenadilla dust and will report back with the results.

 

Last time I had to redress a tone hole, I just built it up a bit, then coarsly shaved it off and finished the whole thing with a spin of a dremel-powered sanding disc. I thought better a tight flat tonehole rim than a porous shaped one, and the pad is sealing perfectly.
I mean, a clarinet's LH ring finger hole is flat as well, and yet it seals.
(I admit that is an amateurish approach, but as it is my own instrument....)

When did shaped/cut tonehole rims become fashionable? And for what reason?

 

So it looks like there are visual clues to see if the glue is still usable. My loctite 406 is very fluid still.

I don't know about the need for accelerator. As I mentioned before in a separate thread, I rebuilt an ebony nut slot on my viola with superglue and baking soda. A drop of superglue in the worn-out slot, then I added a pinch of baking soda - it hardened in less than 1 second. Acid/base thing. A luthier told me he had the same experience with ebony dust and superglue. That is kind of what I'm expecting for my own repair project, though it would probably be preferable to have the ability (working time) to mix the dust with glue first and form a paste.

I'll test this first of course.

George

 

Not to worry. I sort of knew what I was getting into. I am loving the challenge. I see it as an opportunity to learn some new skills and techniques. I have a plan to convert all of the keys to real "keycups" and to adapt all of the posts to accept threaded hinge rods.

The technique you described is the same one used by professional repair techs AFAIK.

 

He wanted it.

Usually for issues like this, since I don't invest in tonehole cutters, it's a careful process of shave, "graft", sand, seal. Those are nasty little buggers of tone holes you've got there, basically kymarto has a point with the gel glue, but sometimes that just looks bloody awful if not done absolutely perfectly, although it's a really simple way to go about it and it works. I tried using the epoxy/wood dust combo once in the same method which worked excellent, and lasted quite a while, since the glue gives the tone hole integrity that it wouldn't have otherwise. It's not enough to have to worry about wood expansion and contraction long term either, but if it needs replacing, it can be troublesome.
With the old instruments you have to be extremely careful when filing anything down, inside, outside, tone hole or not, as the wood is extremely fragile.
Definitely a doable project, but a tedious one.

 

I have experimented with many different combinations of CA glues and grenadilla dust and found some difficult to work with and some impossible to work with.

The very thin CA runs everywhere and is difficult to control where you put it. It has such a fast set up time that it is difficult to get the powder on before it hardens.

When the grenadilla powder is applied to the tonehole first and then the thin CA, the glue just beads up and rolls off.

The thicker gap filling CA is easier to work with since it stays where you put it, but it is difficult to get the powder thoroughly mixed in without leaving gaps when you cut it.

Trying to mix the slower setting CA with the powder first and then applying it creates a chemical reaction similar to baking soda. It smokes and hardens very quickly into a small grenadilla volcano.

The "old stock" thin CA that has thickened a bit and is between the two viscoscities seemed to work the best. The glue can be applied in small amounts and stays where you put it. Quickly sprinkling the dust over the top and then "patting" it into the glue and then brushing off the access was the technique that produced the most satisfactory result.

However, when the CA and dust patch sets, it turns out to be quite brittle. When one tries to cut it with the tonehole facing tool, it is difficult to achieve a smooth finished surface. Sometimes there are gaps left where the powder didn't mix in.

The very best procedure I found was to mix the grenadilla dust with 5 minute epoxy. If you quickly heat the mixture with a heat gun, the epoxy turns more liquid---a trick I learned from Curt Altarac. In this state one can apply the mixture very accurately around the tonehole using a small artists paint brush.

When this "concoction" sets, it cuts very smoothly using the tonehole cutting tools. I have not done any toneholes on the tárogató, instead using the grenadilla dust provider clarinet to practice on.

I have an appointment with Dave Hall who studied with Morrie Backun and is acknowledged as the top clarinet repairman in the state to take a private "master class" on tonehole repair the first week in March. So for the time I am putting part 2 of the restoration aside until after I have met with Dave. In the interim I will concentrate on part 3 which is the repair and upgrading of the keys and mechanisms---something I have more experience with.

 

Here are some things I found from filling and cutting many tone holes.

I have tried many different glues. My favorite to fill tone holes with grenadilla dust is actually thin super glue. I found it glues best to the tone hole (in comparison with thicker super glues). I've also tried various degrees of thicked thin super glue and this worked good too as long as it wasn't too thick already. You need to be careful but IME it's possible to get the thin super glue to where you want it. Like John, I also found it's crucial to start with glue, then add dust. Same as crack repair, putting the dust first will make the glue just soak into the dust and not really glue to whatever is under it much.

I've tried several types of slow and fast (5-minute) epoxy glues. I also thin the epoxy with heat when needed. All were fine in general, but I found some issues. 5-minute epoxies that I've tried (about four types I think) all dried in that time, but took so much longer to become really hard. Even then, they weren't as hard as slow epoxy or super glue for this purpose in a reasonable amount of time. It just seemed to take days to become reasonably hard. Slow epoxy is usually too low, though I use it sometimes for more serious fills (i.e. a big chunk is missing, usually with reinforcement stainless steel).

As far as filling, something that can help is making teflon coated "blockers". Sounds fancy, but this is just some more or less random parts with teflon sheet glued to them, to put where you don't want the glue to go to. You can put rods inside tone holes, tenons, etc. for this. Here is an example of using this method on a "jig" to make an epoxy extension to a key: http://farm7.staticflickr.com/6208/6098983435_a1b89c0bab_z.jpg

For cutting tone holes I use a few tools. Some are hardened steel with teeth. Some I make myself, mostly from plastic or brass rods, with sandpaper glued to them. Sometimes I use something like a boring cutting tool on a mill to cut the tone hole. You can make sure the tone hole is centerd and level by putting a close fitting rod held by the mill inside the tone hole (for centering and leveling).

It's true that a flat surface of a tone hole can work, but the clarinet left hand ring finger is a tricky example. It's closed by a finger and doesn't need to be adjusted with any other key. I think for tone holes closed by fingers, the less sharp edge of "flat" tone holes is actually better and more comfortable. For tone holes closed by keys IMO the thinner and sharper (but not too sharp) edge has advantages. It would require less pressure from the pad to seal. The example I like is from the kids section in the local science museum. They have a chair full of nails you can sit on and a chair with only one nail...

 

Yes, but in that light, "sharp" (as opposed to flat) tonehole and eg leather pads are a contradiction, as a pore right on the rim has the same effect as a scarred or chipped rim, no?

Or is it rather because a sharp tonehole has less surface, hence less chance to develop sticky pads?

(Must consult "The History Of The Woodwind Tonehole"...)

 

It depends on the size of the pores and the thickness of the tone hole rim. Too sharp rims can also tear the pad skin fast (usually bladder but even leather). I tested several leather pads with a thin/sharp tester and magnehelic machine and IMO a thin but not too thin/sharp tone hole rim is better regardless of pad. How thin... hard to say exactly. IMO it's a range anyway, not an exact critical measurement. To judge the width I use one of the most sophisticated tools in the world... my eyes

The main reason is the same as the chair of nails example. The thinner rim requires less force to seal.

 

Here is a photo showing the boring tool method of recutting the tone hole. I don't have any of my own photos of this. This is from the person who taught me this method.

 

It requires less force to puncture. If an impression is at all needed for a seal. But the impression simply increases the area of contact, the deeper the impression, the more surface - it is just folded around the tone hole rim instead of being seated on a flat ring.

I am still not sure that a good flat tone hole rim and a good flat pad requires more force to seal than on a traditional tone hole crown.

 

The tone hole is close to perfect (if leveled) but still not 100% perfect. But more important, a "perfectly" level pad isn't perfectly level at all. In addition, some force is required to make a pad seal. If the pad simply rests on the tone hole with no force (other than gravity), it wouldn't seal. From the moment the pad starts to touch the tone hole until it seals there is some time until the tone hole rim "crushes" those many small "hills" and "vallies" on the pad, thinking about it "microscopically" (is that a word?). Technically, a thinner rim will need less force to crush those hills, just like the example of the chairs. So in theory, the thinnest rim that is not too thin to cause any problems (i.e. cut the pad, thinner than a pore, etc.) is optimal. Whether that makes a difference in practice is definitely debatable. IMO/E it does. However sometimes it's definitely not worth the trouble.

 

Hmm, so why bother with (in the case of saxes) with rolled tone holes?
They provide a bigger surface for the pad to rest on, which would increase the force required for a (microscopically) correct seal...