Replacing reed leathers?

[trek4fr]

My old Excelsior has about 10 reeds where the leathers are bending back about 1/8" to 3/16". I've tried a couple of methods to flatten them but they are old and tired (kinda like me) and have lost their stiffness (kind like...well, never mind). I'd like to replace them but the information I've found on the internet says that if the leathers are replaced, the reeds will need to be retuned. Why is this so? The leather doesn't change the length of the metal reed in any way. So why would changing the leather reeds require retuning the instrument?

 

[debra]

When the airflow is restricted in any way the frequency will go down. This is the main reason why when tuning an accordion measuring the tuning must be done with the reed blocks in the accordion, not on a tuning table. (And in some critical cases it is also necessary to insert the bellow pins (or screws) as the frequency may even change by removing/inserting the pins.
The airflow gets restricted by the pallets (more so in cassotto than out of cassotto because pallets in cassotto open less far). The airflow also gets restricted by the valves. You can place a reed block on a tuning table and then close the valve more and more and notice the frequency dropping.
Normally when you replace leathers with new leathers and glue them properly (not too far), the tuning should be the same as with the old leather when that leather was new. (You might hope that is there was an issue with the leathers when the accordion required tuning in the past faulty leathers were replaced instead of tuning the reeds to work with the faulty leathers.)
Many people nowadays prefer plastic valves over leather ones because they have more predictable and more stable behavior. But some people swear by the use of leathers. (And on large reeds like low bass reeds valves are still always at least partly leather.)
So yes, changing leathers changes the tuning, but most likely replacing the old leathers by new ones will bring the accordion better in tune again rather than out of tune.

 

[trek4fr]

Thanks, Paul. Interesting. I guess I really don't understand this as an accordion seems to work similar to a harmonica and the amount of air through the harmonica, IMO, changes the volume, not the frequency. Changing my bellows pressure (more or less air) makes my accordion sound louder or softer, it doesn't change the pitch.

The main curled up leathers are on the tenor reeds in the bass section (my Excelsior is a 3/4). I'm assuming that if I bought some new leathers of the same length and glued them on at the same exact place, it wouldn't change the tuning much. I'm still debating if I want to mess with it. The leathers are not stiffly curled back. They will fall against the reed plate if it is horizontal. But they will also fall away from the reed plate if it is vertical. Kind of floppy.

So I'll give this more thought as to whether I want to leave it alone, do it myself, or have a qualified accordion fix this for me.

 

[trek4fr]

Hey all, if I decide to take these leathers off and straighten them, or if I decide to install new ones, what are people using now to glue them to the reeds. I know that in the old days shellac was used. Is there a newer kind of adhesive that is being used now?

 

[debra]

When you play a note and then you partly let go of the key and start pulling harder, as you close the pallet more and more (let go of the key more and more) and pull harder to still get some sound, the frequency drops. This is like on the harmonica: if you blow harder and partly close the hole with your tongue the frequency drops.
If large bass leathers are too floppy you need to keep it closed with a spring. This can be plastic but in most cases it is a small mostly straight piece of metal. Look on google images of accordion bass reed blocks and you will see a lot of examples.
As for the glue, people do indeed use shellac, but I learned to use glue that shoemakers use to glue leather (and rubber) shoes. A local clothing- and shoe-repair store here ("Volksbelang") will sell it in bulk if you promise to only use it to repair accordions (not shoes) and if you bring a jar to hold the glue.

 

[trek4fr]

Thanks, Paul. I think I'm going to try some of the advice recommended on a link that Jim posted earlier dealing with leather reconditioning/replacement. I may not fix the problem completely, but I'm skilled enough to not make it worse. Ha ha! If I can't get the leathers straight (and to stay that way for, say, 3 months), I'll take it to an accordion repairman here in Dallas, Texas, USA to get about 20 of the leathers replaced professionally. It would probably be too cost prohibitive to have the entire accordion done, even if I only had the outside leathers replaced. All of the inside ones look good.

 

[debra]

It is also my experience that often the outside leathers are curled up while the ones inside the reed block look fine. I'm not sure what causes this (except in cases where the outside leathers might get caught in the bellows folds).
Replacing leathers on the inside is a lot trickier than on the outside but it should be routine for a skilled repairman. (I'm still a beginner so for me it is a lot harder.) However, if the accordion is really really old you would want to just remove all reed plates and wax and rewax everything and that makes replacing the leathers on the inside just as easy as on the outside, but the whole job (rewaxing) is indeed expensive because time consuming.

 

[JIM D.]

That glue that shoemakers use is really just barge cement. It gets that name from barge owners that have used it in the past to glue old tires to their barge. :lol:
https://www.amazon.com/Barge-All-Pu...8&qid=1498072711&sr=8-1&keywords=barge+cement
I myself use --
https://www.amazon.com/Beacon-Fabri...&qid=1498072823&sr=8-1&keywords=fabritac+glue
It works well with ventilli and leather valves and both can be thinned with --
https://www.amazon.com/VM-NAPTHA-KL...F8&qid=1498073119&sr=8-1&keywords=vm&p+naptha
:tup:

 

[debra]

That glue that shoemakers use is really just barge cement. It gets that name from barge owners that have used it in the past to glue old tires to their barge. :lol:
https://www.amazon.com/Barge-All-Pu...8&qid=1498072711&sr=8-1&keywords=barge+cement
I myself use --
https://www.amazon.com/Beacon-Fabri...&qid=1498072823&sr=8-1&keywords=fabritac+glue
It works well with ventilli and leather valves and both can be thinned with --
https://www.amazon.com/VM-NAPTHA-KL...F8&qid=1498073119&sr=8-1&keywords=vm&p+naptha
:tup:

The shoemaker I get my glue from sells tubes like the first link shows but they do not use that themselves. They use a glue that comes in large tin containers and that is thinned with what I think is the thinner you show. I use that too as the glue tends to thicken over time (even though I always close the lid even between glueing individual leathers or plastic valves). The thinner works very well to restore the glue to its original viscosity. They do not like to sell their good stuff to consumers who are going to then repair shoes. They are only willing to sell their good glue to me because I repair accordions and I got the reference from the old accordion repairman that taught me most of what I know.

 

[JIM D.]

You can also get it here ---
https://www.shoerepairglue.com/

 

[trek4fr]

I went with the Beacon Fabri-Tac. I rolled, ironed, and refastened the leathers that were bent back. I also paid close attention to reglue them to the same spot with the same glue coverage so as to not affect tuning much. I'll give it about 3 months and then reinspect things to see how they are.

Thanks, all, for your help.