G'day bert,

A small particle of solder can be effective ... but the distribution of mass about the reed is altered and the 'voicing' ... basically the mixture of harmonics behind the fundamental note ... will alter. Generally, going the 'dab of solder' route takes some of the edge off the instrumment. If you have one of those 'screamers' voiced for the Salvation Army to play outdoors, this might be a good thing.

A lot of old concertinas go downhill with retuning. The best concertinas I have owned were ones where I handed over a bundle of brass reeds to a maker/tuner and he made brand new steel reeds, keeping to very tight dimensions and consistent voicing. This also produces very tough reeds, with none of the weak points that can result, even from careful retuning, when a fairly large shift is required.

Regards,

Bob Bolton