Fixing Air Leaks and Verdigris in Celluloid

[MusicallyInept]

Hello,

A few weeks ago, I bought an accordion (1960 - I'm told - Settimio Soprani Dick Contino Model), and I've been learning to play it while lurking to glean information about how to maintain and care for it. It seems that the first thing to do in order to rectify a leak in the bellows is to replace the black chamois gasket with a modern foam type. I pulled the bellows pins without any incident and everything separated fine. When I looked closer, the chamois seems to be in good shape, but the hard glue that holds it to the bellows is brittle and easily separating - no big deal. However, the sealing surface on both the treble and bass sides felt like course sandpaper in places. Looking closer, I was confused to see brass flecks with verdigris from reacting with the chamois gasket



Looking closer, I think I figured out why they are there. It looks like the cases were painted white and then brass chips were applied before the fine tiger-stripe celluloid was applied. Whatever brass chips weren't covered by celluloid (or that accidentally got embedded on the outside of the celluloid) were free to react with the chamois. Here are a few more pictures of the accordion and the finish to better illustrate:



When I put on the new-style foam gasket, I want to smooth out the gasket surface to make the best seal I can without damaging the instrument in the process. I mess around with woodworking, and have done some repair to other instruments before, so I have pretty much all the supplies I should need, but I want to run my plan of attack by you guys to make sure I'm not messing up (I've never worked with celluloid).

1. This part is done -> Used the non-sharp edge of a razor blade (the part perpendicular to the sharp part) held at a low angle to knock off the loose brass and burnish the bits that are very well embedded
2. Use a fine brass brush and some alcohol to clear out as much embedded verdigris as possible before encapsulating what's left in shellac
3. Seal the gasket surface with shellac and prevent possible affects from later coats of vinyl sealer and/or lacquer
4. Fill small gap in the celluloid seam with a smear of epoxy
5. 1-2 more coats of shellac
6. lightly sand, then apply Behlen's vinyl sealer, Behlens instrument lacquer, or both
7. put back together and continue learning accordion

Does this sound like a good way forward? Is either the vinyl sealer or instrument lacquer a bad idea?

Thanks!
Ron

 

[debra]

So far so good. You did well. I never prepared the surface so carefully as it doesn't matter. I always just have bare wood on both sides.
What is important is to get a bellow gasket tape of the correct width and thickness. 5x2mm is popular, but each case can be different. The width isn't critical (but you don't want it to stick out) but the thickness is. Too thin and it won't seal properly. Too thick and the bellow pins won't go through the holes any more. Don't force them too hard because you might crack the wood.
Start the tape not too close to one of the holes, and give it a diagonal end. Do not pull/stretch the tape as you apply it. Stay on the outside in the corners (following the rounded edge of the bellows frame). Make sure the tape closes properly, again with diagonal cut, where the two ends meet.
Do both the treble and bass side. When one is in need of replacing the other will also need to be replaced.

 

[Dingo40]

MI,
You'll have it better than new!

My foster-father had a Settimio Soprani c1949, two couplers, ladies size model from new. ( £A80, in the day, or a bit more than 16 week's wages for a skilled artisan.)
I remember noticing the treble keys and palettes were of pressed steel and the body of the keyboard, the sounding board and the levers for the keys were aluminium alloy. It was quite light and " handy" .
Quite an early transition to metal from wood, seems to me.
All the " innards" seemed very nicely finished ( unlike some, where out of sight is out of mind.)
Now, as I remember, the reeds were all either of brass or, more likely brassed. Another nice touch!
What are yours like?