|completely disappear with thicker layers...(I am working on this, although I must say that I noticed a similar obscurity on some of the del Gesus in New York Exhibition).
Anyone with the courage or inclination to try this, I do urge a test piece before stuffing it on your newest instrument.
What are the effects of such a ground? Some things are measureable, SEM pictures show that it is extremely effective as a sealer, not a trace of varnish seems to enter the pores of the wood. I believe this to be a good thing. There is a likelihood that there is a measureable case hardening effect. Subjective effects as reported by musicians who have made comparisons suggests that the instruments play more easily from new and new instruments do not seem to be susceptible to the going back to square one syndrome. Players have given major concerto performances with five day old instruments without fear.
I agree with peoples scepticism about players analysis without measureable back up, but my experiments have not been with just a few instruments, but since l985 when I first started work on this, with at least 200 instruments.
Incidentally, I do not consider that this ground is a part of the varnishing process, more an integral part of the construction. So I treat the components while still on the mould. This procedure also helps to prevent any distortion which could possibly occur by wetting down a closed instrument or by the changes to hardness and tensions of individual parts. The slurry of salts is applied very thinly with a rag, about the constituency of well thinned paint which runs off the brush. (I dont know how else to describe it). The ground application will dry by evaporation in a couple of hours, but I leave mine overnight before clearing with rosin oil.
I hope this has been of interest to some.
SOURCES OF MATERIALS.
Mineral Ground paper Page 4