Repairing Roll Harmonica
By Spencer Chase
It is possible to repair and refit Rollmonicas. Their cases are brittle but repairs can be made with epoxy and cyanoacrylate glues if done properly. The main problem seems to be the cork gasket which dries out. In the case of a harmonica transplant, even a good cork gasket would not likely match both parts. Also the weakened old plastic would not have enough strength to compress the gasket without breaking.
The solution is to make a new gasket out of 1\16" closed cell neoprene foam. It has just the right properties to seal without breaking parts. You might have to relocate the brads which hold the harmonica in place to accommodate the difference in thickness of the new and old gaskets. The case gasket also hardens and usually has to be replaced, especially if the case has warped a little. Pure surgical grade latex tubing works well. It can be obtained from laboratory supplies and some hobby shops.
The harmonica itself is not easy to repair. They were thrown together rather quickly with no regard for future repair. The brads that hold them together are likely at different angles and all bent. They should be eased out very gradually and identified to allow them to be put back in the same position.
If reeds are missing or damaged you need to be a real pro to do it. If the reeds are even a little bent out of the ideal location in the plate, they will sound unevenly or not at all. Careful coaxing can get them even if they are not damaged. You can make a little cup to fit over the read, connected to a piece of tubing, to test the reads without putting the thing back together each time.
There are little valve like flaps that always seem to be curled and dried up. I have replaced these with light weight motor cloth but have no idea what their function actually is. They don't really seem to be capable of acting as valves which they appear to be. Maybe the original material had just the right stiffness to act as a valve and may have allowed the Rollmonica to work as well under suction as under pressure. Any ideas about what material to try or what the little things really are?
The things are real cute, but unfortunately most of the "music" is terrible. I'm sure arranging for a 12 note "instrument" is not an easy job.
Spencer Chase
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(Message sent Mon 3 Mar 1997, 06:03:20 GMT, from time zone GMT-0800.) |
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