Leaky Reed Chambers

[David Barnert]

My 30-year old Dickinson Wheatstone 46-key Hayden (the one on the left) is misbehaving. Four adjacent reed chambers are leaking into each other, such that when I play any one of the involved notes one or more of the others can be heard to a greater or lesser extent, both on the squeeze and the draw (no difference).

I've had a look inside and see nothing obviously wrong. Holding a straight edge up to the back surface of the action box doesn't reveal any gaps and similarly applying it to the chamois atop the reed pan doesn't identify a leak.

Unless someone has a better suggestion, I'm assuming that replacing the chamois is what is needed. Any suggestions as to what kind to look for and where to buy it? What kind of glue to use? How long to let it dry? Anything to keep in mind when removing the old chamois?

Or should I have a pro do it?

Is this likely due to the record cold weather we've been having (2nd coldest February since records began)?

Like so many others in this group, I have Dave's maintenance book and can't find it.

 

[david robertson]

Before you start pulling out the old chamois seals, it's worth checking that the reedpan support blocks in the bellows frame are still in place and firmly glued.

If you can't feel or see any movement of the reedpan, and it feels like a reasonably tight fit, it is unlikely that the seals are the culprits. But if the reedpan is a little loose, it's far better to lift the bellows end seals and stick some thin card under them than to try to replace them. You'll notice that the leather binding of the bellows frame wraps over the chamois seal by 1mm or so. If you replace the chamois, you will also have to rebind the bellows ends to hide the edges of the new chamois.

A ruler across the reedpan, by the way, is not an infallible guide!

[Greg Jowaisas]

Chances are the leaks are all clustered in a corner and the prime suspect would be a creeping support block. Sometimes they appear tight but with a little pressure reveal they are only holding on by a thread (of chamois).

 

This has been a tough North American winter. I've been fighting to keep the our little house's humidity above 40%. Wood that loses enough humidity can change shape and that can cause glue to come loose as well.

 

Greg

[JimLucas]

My 30-year old Dickinson Wheatstone 46-key Hayden (the one on the left) is misbehaving. Four adjacent reed chambers are leaking into each other, such that when I play any one of the involved notes one or more of the others can be heard to a greater or lesser extent, both on the squeeze and the draw (no difference).

 

This sounds very similar to a problem I reported recently, except more clear cut. Obviously, there's leakage between/among the chambers, though the offending gap(s) may be too small for your eye to clearly identify.

 

Before you experiment (since that's what it would be) with something more drastic and especially something more permanent, try the following:

• You know what chambers are involved, so just cut a piece of paper (ordinary writing/computer paper should do, though you may want to start with something even thinner) to slip in between the reed pan and the lining of the bellows end that it sits in. Size it and place it so that it will just cover the ends of all four chambers top to bottom, including the edge of the reed pan itself. Now insert the reed pan without shifting the piece of paper, and reassemble the instrument.
• With luck, that extra layer of material, pressed against the "chamois" by the chamber partitiions and reed pan itself, will be enough to seal the gap(s). If not, and before going further, you might try both thicker and thinner layers of paper. (In my example, to my surprise, a standard thickness didn't stop the leak, but a thinner one did.) If you're still unsuccessful, you can try something similar on the partition tops, though in my experience that's less likely to be where the leakage is occurring. Before giving up entirely, you can try sides and tops both separately and together.
• Assuming that the paper does solve your problem, you can
  • Simply leave it there, at least if you only rarely remove the reed pan. You might even want to try removing the paper(s) once the weather returns to normal.
  • Replace the paper with thin leather -- still without glue, -- e.g., if you feel the paper has changed the tone quality of those notes. Still totally reversible. (On a couple of instruments suffering from reed pan shrinkage I did this with somewhat thicker leather, and years later I've not yet found it necessary to make a more permanent "proper" fix on them.)
  • If you insist on doing something permanent, you should carefully lift the relevant section of the existing leather/chamois lining the bellows end and put the added thickness (paper or leather) underneath it, then glue it back down (with a very thin layer of glue; since you don't want it to stiffen the chamois).
• If (as David R. and Greg J. have suggested) the offending chambers are clustered in a corner, so that a loose or shifted corner block is the suspect (causing leakage across the tops of the partitions, rather than around their ends), then
  • If the corner block is loose, glue it firmly in place -- being very careful of the positioning, -- using a water soluble glue. (In the US, I would use Franklin brand "liquid hide glue"; much easier than hot melt.)
  • If the block is firmly in place, try laying a shim of paper or card stock on it and replacing the reed pan. This is a process similar to my above description, and still totally reversible. If that does the trick, then you can make it permanent with glue.
• If the paper/leather shims don't solve the problem, you'd best have the professionals (your friends at the Button Box, I presume) evaluate the problem.

Edited March 7, 2015 by JimLucas

[Doug Barr]

David...send it to Greg....he will fix it up for you. Don't try to do it yourself.

[David Barnert]

OK, I took it apart again and pulled out the reed pan. The affected notes (four adjacent notes would almost have to include a corner as there are six corners and 25 notes) are all near the lower left corner, and lo and behold, the triangular reed pan support block in that corner came off in my hand when I touched it. David R and Greg get full marks, and thanks all for participating.

So now the question is what kind of glue? I have standard yellow carpenter's glue, but something tells me the answer is not so simple. Also, is there a trick to making sure the block is positioned exactly correctly when it is glued? Putting the reed pan in place and working through the other end won't work because the bellows are in the way and I can't see the support blocks. I may just have to go by the fact that the space between the bellows folds and the chamois gasket is really no wider than the block, so there's not much room for error.

 

[JimLucas]

So now the question is what kind of glue?

 

I would once again recommend Franklin Liquid Hide Glue. It takes while to set, which gives you plenty of time to get the positioning just right, but once it's "dry", it should hold the same as hot melt hide glue.

 

Also, is there a trick to making sure the block is positioned exactly correctly when it is glued?

 

Is there not even a faint outline of where the block was originally glued in place? That's certainly what I'd use, if I could.

[Theo]

 

So now the question is what kind of glue?

 

I would once again recommend Franklin Liquid Hide Glue. It takes while to set, which gives you plenty of time to get the positioning just right, but once it's "dry", it should hold the same as hot melt hide glue.

When I've used it I've found it a poor substitute, not nearly as strong a bond as hot hide glue.

 

But in this application a modern glue is quite acceptable imho. If a block needs to be removed it can easliy be split off at the glue line with a sharp chisel, or simply pared away with a chisel. Support blocks can come under quite a lot of pressure in resisting any tendency for a reed pan to warp so the need for a strong bond is paramount.

[David Barnert]

 

Also, is there a trick to making sure the block is positioned exactly correctly when it is glued?

Is there not even a faint outline of where the block was originally glued in place? That's certainly what I'd use, if I could.

Indeed, there is. But did you not say earlier:

(In my example, to my surprise, a standard thickness didn't stop the leak, but a thinner one did.)

I took that to suggest that if I glued the piece in place and its position was imprecise by the difference between the thicknesses of the two pieces of paper you mention it might not solve my problem.

 

In any case, the deed is done. It's in clamps as I type this. We'll see how it works later.

 

 

[David Barnert]

Well, when I put it all back together, the problem wasn't solved. On close inspection, as I feared (see above), the support block could have been a little closer to the end, and since it had only been a couple of hours since I glued it, I tried to move it. I had used Titebond Genuine Hide Glue (manufactured by Franklin International) which says on the label "...clamp for a minimum of 30 minutes. Do not stress joints for 24 hours."

 

But this one wasn't going anywhere. I could neither move it nor pry it off. So I applied a few layers of sticky paper (cut from the end of a Post-It note) to the upper surface of the block and reassembled the instrument.

 

It seems to play fine now, but this is hardly a permanent solution.

 

One of these days, when the spring morris dancing season isn't looming, I'll take it to the Button Box and see what they can do with it.

 

[david robertson]

I wonder why you don't think this is a permanent solution? If I had a quid for every support block I've seen 'adjusted' with little bits of paper, card, felt and chamois leather, I could probably afford to buy a decent Vernier caliper...