Treble slider leaks on Paolo soprano CBA

[AccordionCol]

Hi, I have an old Paolo Soprano CBA that is leaking a lot of air on the treble side.
Along with some bleeding notes there is also an excessive amount of air that seems to be coming out of the sliders when they are closed.
My questions are… when the slider are closed should air be completely shut off?
And if so, how can I make them air tight?
Thanks

 

[PhiliGol]

Hi Col
Not sure what you mean by "sliders" - the pallets which should be lifted one a key resp. button is pressed or register sliders?
In this case it's most likely the pallets topping glued to them.
It's a layered material consisting of felt (the flexible part) an leather (to make it airtight).
Also there are valves paired with every reed - inside the instrument.
If they're loose or curled it adds-up to overall tightness.
If you browse through the four you'll find a lot of pictures showing pallets and valves.

As long as no button is pressed the instrument has to be airtight.
No matter whether you pull of push the bellows - it should need quite a power to move it - with no tone sounding.

IN any case it needs some inspection to find the root-cause - remotely diagnosing an air leakage may get you on a wrong path.

 

[debra]

When all the sliders (inside, under the reed blocks) are closed then the amount of air that still goes through should be minimal. But some air loss there is unavoidable because the sliders must have room to slide open and closed. How are you measuring that the air loss is through the sliders? Normally, when you are not pressing any notes or buttons there should be no air loss because the bellows gasket tape seals the three main parts (treble side, bellows, bass side) together, and the pallets close off all the holes where the sound comes out. There should be very little difference in air loss with the sliders open or closed because the pallets close everything off. If you have noticeable air loss without playing then air leaking through pallets that don't close properly, or air leaking through old and worn out bellows gasket tape are some of the most common sources for the problem.

 

[AccordionCol]

Iv repaired leaks in the bass side, repaired bellows leaks and replaced the gaskets on both sides. Next obvious issue is bleeding notes in treble when no buttons are pushed. There are 2 or 3 notes bleeding which require new pallet facing, however I feel that doesn’t account for all the air loss as it’s considerable. I’ve taken the pallet cover off, sealed all sliders shut and can still feel a considerable amount of air coming out of the sliders at one end.
Are there other common air leak issues on the treble side aside from the pallets?

 

[Glug]

One thing you can do is make a stethoscope to listen for where the air is coming out.
I bought a cheap 'medical' stethoscope off Amazon and replaced the cup end with a piece of 1/4" brass tube.
You then move the tube around where you think the leak might be and there's a rushing sound when you find it.

The other thing worth considering is using masking tape to seal off sections of the accordion so you can localise the leaks.
Have a look at https://www.accordionists.info/threads/air-leaks-lucia-iv-p.5243/#post-58566

Edit: On that Lucia one end of the treble slider layer was leaking and I sealed it with silicone automotive gasket sealant.

 

[boxplayer4000]

AccordionCol: The subject of accordion air leakage is massive. Without more knowledge of your instrument the experienced people on this site will just be guessing.
My tuppence worth is that air leaks fall into two categories: those which happen when the instrument is being played and those which are present when it is not being played ie. keys/buttons not being pressed. Leaks are located by a process of elimination and are located by listening, feeling and with lights in some cases. The subject is well discussed elsewhere on this site.

 

[boxplayer4000]

AccordionCol: The subject of accordion air leakage is massive. Without more knowledge of your instrument the experienced people on this site will just be guessing.
My tuppence worth is that air leaks fall into two categories: those which happen when the instrument is being played and those which are present when it is not being played ie. keys/buttons not being pressed. Leaks are located by a process of elimination and are located by listening, feeling and with lights in some cases. The subject is well discussed elsewhere on this site.

 

[debra]

I worked on an old Paolo Soprani that had a treble side that didn't seal properly to the bellows because on one end the cassotto hit the bellows frame. I had to make a cutout in the bellows frame to get the treble side to seal to the bellows frame.
To test whether the pallets seal properly, use the cigarette paper test: press a key, place a cigarette paper under the pallet, release the key, then check how much force you need to pull the paper out. That should be about the same force for all pallets. When the paper is pulled out easily the pallet isn't closing properly and the lever needs to be adjusted (using "torciferri").

 

[AccordionCol]

Ok cool, thanks for all the info. I’ll take a closer look and see what I can find and also scan the other threads. If anyone has any other suggestions they want to pass on please do.

 

[boxplayer4000]

A cheap stethoscope (with the 'sounder' removed) will let you hear air leaks which are normally inaudible.