For hardening, sandarac has its place and usefulness, although, as with the naturally soft gums and resins which return to their original condition after the solvent has evaporated, great care must be taken to use a very small proportion.
A mixture of sandarac and sh.e.l.lac will result in an extremely hard and almost insoluble varnish, a very undesirable covering for a musical instrument of any kind as it wears badly, that is, suddenly and harshly with a rough fractured edge, instead of the gentle thinning-away under usage, seen with a delicate yielding material.
Acroydes is an Australian "gra.s.s gum," with very little recommendation, as in any considerable amount, it impairs the transparency of the other gums with which it may be mixed.
For a brown colour, a little burnt sugar will give a good tint, although too much will spoil the consistency of the other ingredients, and the whole will be easily affected by damp. Aloes, of which there are several kinds, have been used as a colouring ingredient, but the results are not on the whole to be considered as good.
Of the different lacs, or as it ought to be termed, condition of the resin, as they are all from the same source, seed lac and garnet lac, in proportion with other resins, will be found to have considerable colouring matter and requiring very little in addition.
For our present purposes, those of varnishing fresh parts of injured violins, the above mentioned component materials will be found, when in good proportion, according to the experience of the operator, to be nearly all that would be desirable in imitating the surrounding work.
There is nothing that can be suggested to enable a careless or incompetent repairer to achieve good results without care or calculation, and these two are an absolute necessity when the repair and restoration of a violin at all worthy of the name is the subject in hand. Innumerable effects may be obtained by changing the proportion of groundwork or priming, and top or coloured varnish. As the celebrated old Italian varnish was not one kind but very many different kinds, it is more than probable that the different results obtained by the celebrated liutaros consisted to a greater extent in the manner of the application than any wonderful quality of material. Of this subject much might be written which would fill many times over the capacity of our present volume.
A few words more may be said in conclusion regarding the varnishing of new work on old violins; it must not be supposed that for the imitation of the surrounding work an exact repet.i.tion of the old Italian process with the identical substances used by the liutaros would be absolutely necessary for perfect or near success; it must be borne in mind that old varnish near the spot with its partial decay, probably from many causes, has to be imitated, and that what would be a great success with regard to a small s.p.a.ce, might in all probability prove a signal failure when the whole instrument is so treated.
As a final stage, a freshly varnished portion (and over newly inserted wood), will require a little rubbing down (as it is termed); this may be done with some of the finest and worn gla.s.s-paper, finely ground pumice and oil, with a last turn of tripoli powder or rotten stone with oil. This should be done only when the varnish is quite dry and hard.
THE END.