I’m sure you would be most welcome. Being a bit of a traditionalist I expect yours will be a pint of ‘Newcastle Brown Gum’ and a ‘Scotch’ chaser ?
As regards sealing I think we are a little at cross-purposes here.
The shimming I mentioned goes behind the chamois seal that you see on the inner faces of the bellows end frame when the pan is removed. Shimming behind this inner piece, which I call a ‘skirt’ when it is loose, will effect a tighter seal on the edges of the reed pan itself and on the ends of the partitions.
On many old concertinas, however this skirt is actually glued to the inner face of the bellows frame.
Having said that, I have unglued and shimmed behind such a seal in order to marry up bellows and reed pans from two scrap instruments…Ah! The wonders of reversible glues!
As regards the partition seals that mate to the action box, the key points to consider when renewing them are:
- With the old seals removed and the old glue residues cleaned off, place the pan face down on a flat surface and check for any significant warping by trying to rock it.
- Ensure even thickness (and texture/density) of the new seal material and take care not to ‘thin’ it by stretching while ‘placing’ it.
If you get the above right, you should have no problems obtaining a good seal.
In effect you are starting with a flat surface and adding the same thickness throughout.... result = flat surface
After all, the whole idea of the chamois seals is to take up and allow for any minor
irregularities between the mating surfaces.
Do remember, only a very light application of glue is required. Too much and it will soak into the seal and harden to create ‘high spots’ and possible leakage. Just place each section onto the glue as gently as possible and then invert and gently press down each new seal on a flat surface is to ensure even glue distribution. When you think about it, these seals are held in compression and the only requirement of the glue is to stop them falling off when the instrument is stripped down for repair or maintenance.
Though I have heard of a sheet of glass being used in this way, I have never tried it myself. The only way I can see that it would be of any use is if one could visually judge (thriugh the glass) how compressed a section of chamois seal is when say finger force is applied; air leakage being, of course, invisible. I have just tried it out using an old reed pan with well bedded in seals and could determine no visual differences.. I can however imagine that with well textured and, as yet uncompressed, new seal material, some differences might be visible.
I would love to hear from anyone who uses the ‘glass trick’ to useful effect.
I suspect it may be of some use when building new instruments or compensating for warped reed pans but my feeling is that under normal repair circumstances, the guidelines set out in the various postings in this thread should suffice to give good results.
The above ‘general guidelines’ will of course only hold true if the reed pan is free of significant warping.
Hmmm……I feel a 'warped reed pan' thread coming on….