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[YLB]

Hi!

I decided to MIDIfy a melodeon(*) as a hobby project and found a perfect candidate for this, an old Hohner club IIb in quite good condition (except the reeds but it doesn't matter). Bellow is really fine and mechanical parts are working perfectly, there are just a few little scratches here and there but overall it seems to have slept in its box for a long time.
Before filling it with electronic parts I would like to clean it thoroughly and try to improve some points with your help and experience as this is my first restoration project

1) corrosion
There are little spots of rust on a few steel parts and a kind of green/yellow layer here and there on other metallic parts like the levers where the buttons are attached (I don't know what metal they are made from, zinc? aluminum?) . What should I do to remove it and ensure that it won't spread?

2) unwanted noises part I
Squeaky ones, specially on the bass side. The buttons can move a bit in their hole and when pushed or released, there are hits, friction and noise. Is there a way to secure them more tightly in their hole so they are always centered and silenced?

3) right hand keyboard improvements
They too are not perfectly centered and sometime scrap the covering plate at the risk of being stuck if pushed really hard. For the now there's a layer of felt underneath and I will change it with a thicker one but this will only solve the vertical travel problem. Is there a way to limit their horizontal movement? I've been used to staircase keyboards and would like to try to get close to this feeling 

3) unwanted noises part II
I know it's a trademark of Hohner but as I will have to modify pallets for this project, is there a way to silence them a bit in the same process? For the now it is a layer of (old) leather but is there a possibility to use a more modern material with a better cushion effect?

* I don't know if its popular here but be sure that I will only do minimal modifications to the instrument and not butcher it to the point I won't be able to revert it to its original acoustical state 

[Steve_freereeder]

What sort of condition are the reeds in, and what do you propose to do with them? Please don't throw them away. Some folks on this forum will be looking for a set of Hohner reeds, and unless they are truly rusted to bits, they are worth salvaging.

[Rob2Hook]

Much of what you are hoping to achieve is included in a deluxe fettling of a Hohner!

1)  I believe the levers and most of the metal parts on vintage models are nickel plated steel.  The verdigris may scrape or scrub off, but care will be needed to avoid scraping right through the surface and it may rust.  Of course, I may be wrong about the materials used so let's hope that the professionals will come along to confirm or correct this.

2) Unless you're willing to build a whole new bass mech, it will always make some noise.  It can be improved by reaming out the holes in the body to allow a felt bush to be fitted, holding the buttons central and making a non-squeaking contact.  The other thing to help stop the clatter as the buttons are released is to reface the pallets with a felt/leather material to cushion the closure (and seal better).  The jury is out on putting lubricant on the pivots - it risks contaminating reeds and airways and attracting dirt.  Perhaps this will not be such a problem once converted to midi?  Those who advocate lubrication seem to favour small amounts of either graphite dust in a vaseline carrier or dry PTFE spray.

3)  The pre-war Club IIB I have has a removeable rear to the keyboard, so a thicker felt (also new and therefore more springy) can easily be fitted.  This will not only cushion the end of the vertical button movement but also limit that movement.  Once the buttons can no longer go too deep they should not be able to catch on the faceplate.

4) The treble keys will also benefit from re-lining the pallets, just like the bass ones.  New felt/leather lining will both cushion better and help seal leaks under the pallets you never even knew you had.  The old leather will be too hard to do its job effectively.

Earlier posts will give you guidance on the techniques to do all these jobs and which materials have proven best.  I'm sure the "fettling" community will add the details over the next few days.  As Steve has said, there is a ready market for old but serviceable Hohner parts, so don't throw anything away!  Many are considered better than their modern counterparts and particularly reeds are always needed by repairers and tuners to match the period sound.

Rob.

[Lester]

Normally (?) when going reedless the whole mechs both bass and treble as ditched and replaced with switches. The bellows are allowed to inflate/deflate though a small bleed hole whilst the pressure positive (push) or negative (pull) is detected by some sensor to determine the bellows direction and thus note to be generated against the treble/bass button being pressed.

So I'm not sure how any of your questions are relevant but I'm open, as always, to being educated.

[YLB]

Thanks guys!

What sort of condition are the reeds in, and what do you propose to do with them? Please don't throw them away. Some folks on this forum will be looking for a set of Hohner reeds, and unless they are truly rusted to bits, they are worth salvaging.

I will not throw them of course!
Some of the reeds are a little rusty, other are in good condition and none of them are broken. They could totally be fixed to a playable state with a bit of work. For the now I will carefully store them out of moist and light.

Much of what you are hoping to achieve is included in a deluxe fettling of a Hohner!

1)  I believe the levers and most of the metal parts on vintage models are nickel plated steel.  The verdigris may scrape or scrub off, but care will be needed to avoid scraping right through the surface and it may rust.  Of course, I may be wrong about the materials used so let's hope that the professionals will come along to confirm or correct this.

I remembered my chemistry courses and thought to sink them in a ionic solution but I have to find which one would do the trick. Or polish them then use some kind of oil to protect them

2) Unless you're willing to build a whole new bass mech, it will always make some noise.  It can be improved by reaming out the holes in the body to allow a felt bush to be fitted, holding the buttons central and making a non-squeaking contact.  The other thing to help stop the clatter as the buttons are released is to reface the pallets with a felt/leather material to cushion the closure (and seal better).  The jury is out on putting lubricant on the pivots - it risks contaminating reeds and airways and attracting dirt.  Perhaps this will not be such a problem once converted to midi?  Those who advocate lubrication seem to favour small amounts of either graphite dust in a vaseline carrier or dry PTFE spray.

Fortunately, I don't need any kind of lubrication on pivots, only the buttons are producing noise. I'm a little afraid to enlarge holes, would teflon tape do the trick?

3)  The pre-war Club IIB I have has a removeable rear to the keyboard, so a thicker felt (also new and therefore more springy) can easily be fitted.  This will not only cushion the end of the vertical button movement but also limit that movement.  Once the buttons can no longer go too deep they should not be able to catch on the faceplate.

4) The treble keys will also benefit from re-lining the pallets, just like the bass ones.  New felt/leather lining will both cushion better and help seal leaks under the pallets you never even knew you had.  The old leather will be too hard to do its job effectively.

It is a post-war model I think (with rounded shapes) but I can easily remove the keyboard body part. I know someone who has access to various kind of leather. Is there a preferred one and/or a preferred thickness?

Earlier posts will give you guidance on the techniques to do all these jobs and which materials have proven best.  I'm sure the "fettling" community will add the details over the next few days.  As Steve has said, there is a ready market for old but serviceable Hohner parts, so don't throw anything away!  Many are considered better than their modern counterparts and particularly reeds are always needed by repairers and tuners to match the period sound.

Rob.

I have to admit that for the now I studied the electronic part of the project and only discovered this forum a few days ago. I'm aware of the value such an old instrument has and that's why I want to take care of it in a proper way 

Normally (?) when going reedless the whole mechs both bass and treble as ditched and replaced with switches. The bellows are allowed to inflate/deflate though a small bleed hole whilst the pressure positive (push) or negative (pull) is detected by some sensor to determine the bellows direction and thus note to be generated against the treble/bass button being pressed.

So I'm not sure how any of your questions are relevant but I'm open, as always, to being educated.

I want to do my best to keep the feeling of playing a real one and be able to revert it to its original state if needed. This project in particular caught my attention because of the minimal changes to the original accordion. I'll go the same way (opto interruptors and pressure sensor) and adapt it to our favorite beasts. 

[Steve_freereeder]

The treble keys will also benefit from re-lining the pallets, just like the bass ones.  New felt/leather lining will both cushion better and help seal leaks under the pallets you never even knew you had.  The old leather will be too hard to do its job effectively.

It is a post-war model I think (with rounded shapes) but I can easily remove the keyboard body part. I know someone who has access to various kind of leather. Is there a preferred one and/or a preferred thickness?

Charlie Marshall supplies the proper stuff. He ships world wide.
http://www.cgmmusical.co.uk/CGM_Musical_Services/Welcome.html

specifically:
http://www.cgmmusical.co.uk/CGM_Musical_Services/Felt_Leather_Pallets.html#4

I'm aware of the value such an old instrument has and that's why I want to take care of it in a proper way 

You have a nice old Hohner there. In my opinion it would be a much better idea to restore the instrument to its former state using the original reeds and find another, less precious, box to do your electronic conversion.

[YLB]

You have a nice old Hohner there. In my opinion it would be a much better idea to restore the instrument to its former state using the original reeds and find another, less precious, box to do your electronic conversion.

As strange as it could seem, it was the cheapest accordion I could find in good (almost playable) condition. Hohner club, because of their keyboard layout, are less and less popular in France where the standard is G/C with low notes. Luckily for me, France share a border with Germany and its eastern part have been heavily influenced by the tunes and the club system used to play them, so they are (or were) popular there. But nowadays they are ditched for newer models and everywhere else in France everyone is looking for less flashy, wooden models in the Italian style, Castagnari being the must have (I don't agree here but it is the general consensus).
Add to that the fact that diatonic accordions are a niche market in comparison to chromatic ones (musette anyone?), fitted with buttons or piano keys, and you'll understand that second-hand Hohner club logically were the best candidates for this project, specially if I'm aiming for a 2 rows+5/at least 8 basses and a total of 300€ including electronic parts. I got lucky and bought it for 120€ including shipping fees (about 20€).

As I said before, I'm not a savage and I won't butcher it  . Only minor changes to the pallets (with a better system than what is done in the project I linked) and one small hole near the top of the grille for a few wires.

[Theo]

You asked about corrosion on the mechanism.  Usually these are just plain mild steel, sometimes there is a zinc coating but that is unusual. If it is very slight, or just a thin surface layer you can ignore it. It has taken many decades and that is all that has happened.  You can clean the parts with a wire brush or steel wool or Scotchbrite, but it's best not to apply any surface coating.