Need an opinion on potential air leak

[Azalin]

Hello folks,

 

I'm having a weird problem with my C/G concertina. The left hand low B on the pull seems to be leaking (ghost note) but *only* before I play the lower F# also on the pull. When I play the F# right after the B, I can hear the B ghosting a bit. As it happens, both these reeds and pads are next to each other. I replaced the pad for the B but I don't think it made much of a difference. Maybe it's just a series of coincidences and I'll do some testing, but I was wondering if anyone had an opinion on this. Could it be that there's a leak between the pad board and the reed board? I check and didn't see anything obvious.

 

EDIT: I tested some more and yes, if I play the B and then the F# right after, as long as I keep pulling I can hear a faint B... but if I play the F# by itself first, nothing. 

Edited May 24, 2020 by Azalin

[Alex West]

I have this sort of problem regularly when rebuilding bellows and reseating reed pans on old concertinas (sometimes due to warping that I don't want to simply sand away).  Look for leaks in any of the gasketted areas where these adjacent chambers connect - around the sides, on top of the chamber walls etc.  It doesn't need much of a gap to create this kind of ghosting.

 

Also check the closest reed pan support.  Maybe that's slipped a little and has created an air-path?

 

Alex West

[Azalin]

Thanks for your answer. Actually now it's getting worse and I got the same problem on the right side, two different notes not adjacent that are ghosting. If I were to send it for maintenance, what type of work could be done to try to fix this? It seems to be systemic. I've looked everywhere and I don't see anything abnormal but I'm not very qualified for this sort of thing.

Edited May 25, 2020 by Azalin

[David Barnert]

Are the two notes that are interfering with each other at a corner of the action board? If so, check that the little triangular wooden prism that supports that corner of the reed pan hasn’t come unglued.

 

Is it possible the instrument needs a new chamois job?

 

2 hours ago, Azalin said:

two different notes not adjacent that are ghosting

 

Do you mean the buttons aren’t adjacent or the pads aren’t adjacent? I can’t imagine air from one chamber causing trouble in a chamber that’s not adjacent. Whether the problem is the triangular wooden prism referred to above, the chamois, wood warping, or pretty much anything else, the leak is certainly where the action board meets the chamber with what should be an airtight seal.

[Azalin]

I meant two different chambers, not next to each other. I get the feeling the whole thing is warped a bit somehow and leaking "everywhere". I'll take a look at that trianlge tomorrow thanks, haven't noticed any such thing.

 

What's a charmois job? But by the sound of it I'm thinking it's quite possible ?

[David Barnert]

1 hour ago, Azalin said:

What's a charmois job?

 

If it’s a traditionally constructed concertina, the soft material glued onto the top edges of the chambers that forms the seal with the action board is chamois.

 

 (apologies to concertina connection.com)

If it’s getting old and compressed or needs regluing, that could explain the leak.

[Azalin]

Yes thank you David, I get the feeling that's exactly what the problem is. It seems to be ghosting notes "everywhere" and I tried to play with a knife to "fluff" the leather but it doesn't move at all so I'm guessing I'm out of options without something more advanced. Anyway I will send it to Paul Read in Toronto as it requires masterful skills I don't possess 

[David Barnert]

9 hours ago, Azalin said:

Anyway I will send it to Paul Read in Toronto

 

He’ll know what to do.