This section is from the book "Spons' Mechanics' Own Book: A Manual For Handicraftsmen And Amateurs", by Edward Spon. Also available from Amazon: Spons' Mechanics' Own Book.
Polished woods are chiefly employed in furniture making, hence wood polishes are most commonly known as furniture creams. They are also often termed French polishes. The operation of wood polishing consists in nothing more than the distribution of a solution of lac in spirits of wine - by means of a rubber made of cotton wool and calico rag - over the surface of wood, using pressure, until the pores are entirely filled, and the strata of deposited resin adhering form a smooth, hard, and brilliant glaze. The first operation in polishing is called "filling-in" - that is, some substance, other than polish, is rubbed into the pores of the wood to economize time and materials; in fact, this is the foundation on which the superstructure is built; consequently it is of no small importance, as good beginnings generally make good endings. The general modes of filling-in are multiform, the following being a few of them : - Plaster of Paris is the most common ingredient, and is thus used. Roll up a piece of rag into a rubber, saturate it with water, dip it into the plaster, taking up a goodly supply, and rub it well into the pores, bit by bit, until you have as it were plastered or whitewashed the article of furniture all over, taking care, however, to wipe off the superfluous plaster with another piece of dry rag, before it sets; otherwise there will be difficulty in getting an even surface without much papering.
When this is done let it stand till thoroughly dry.
Another method is to beat up some plaster in water sufficiently thin to prevent setting too soon, and go over the wood with this as before. Some beat up plaster in linseed-oil, and use that alone; while another adds a little polish stirred into the above, to cause it to set a little quicker. Another compound is Russian fat, plaster of Paris, and some pigment to suit the wood it is intended for; these are heated together and laid on hot, wiping off the superfluous mass with rag. The only advantage in the two last being, that polishing can be commenced upon them directly, whereas the others have to dry first. Some even utilize mutton-suet in its solid form, to rub into the pores, others melt size, and stir in plaster, using this hot, which is as good as any; for, when dry, it does not absorb so much oil as the plaster and water methods.
A system that was practised for some years consists in dissolving alum in cold water, until the water will take up no more; in other words, a saturated cold solution; powder some whiting, and pour into it the alum solution; decomposition with effervescence takes place, the sulphuric acid quitting the alumina, and seizing the lime by its superior affinity, driving off the carbonic acid, which is set free, thus producing sulphate of lime, with a little alumina and potash, or ammonia, instead of carbonate of lime and sulphate of alumina.
This is cheap, easily made, and is a powerful astringent; containing more acid than plaster, which is also sulphate of lime with the greater part of its acid driven off by heat.
The next operation consists in oiling the wood with linseed-oil; but previous to this, it should be well papered with glasspaper No. 1, or coarser if required; then take a piece of cotton wool, saturate it with the oil, and go carefully over every part that shows white from the filling-in, taking care to "kill" that filling-in, as it is called, or totally obliterating it. This done, wipe all the superfluous oil off, thoroughly; bearing in mind, the less there is of this in your foundation, the more solid will be your work.
Now roll up a piece of cotton wool into a compact and suitable rubber, pour into it as much polish as it will hold; cover it over with a piece of open calico rag, and pass this over every part in a horizontal direction, floating the surface with polish, which must then be set aside to sink and harden. There should be no attempt at polishing in this operation, the first consideration being to obtain a good concrete to build upon.
When properly dry, the fibre, which has risen from the floating coat of polish, must be thoroughly papered down with glasspaper No. 1 1/2, and if upon a flat surface, a cork rubber will be necessary; for no work, however highly-laboured out, will acquire an even and proper surface unless it is well grounded. A practical man knows the importance of this; how it saves him time and labour; therefore he is very careful not to begin polishing before his foundation is perfectly satisfactory. This being so, the process of polishing is commenced. The rubber used for floating the work will answer for this purpose, provided it has been kept moist by excluding air from it.
The rubber being charged with polish much less copiously than in floating, a piece of calico rag is placed over it, and so twisted up, that the excess of rag and rubber is confined in the palm of the hand; and with this arrangement the polish is conveyed to the wood. The polisher now proceeds to body-in his work, using, occasionally, pumice powder sprinkled over the surface, which not only keeps that surface smooth, but materially assists in filling the pores; in fact, it is invaluable in the hands of a skilful man.
As a solid foundation is a great desideratum, he applies as little oil as possible; just sufficient to prevent dragging of the rubber, which would produce a harsh and uneven appearance. The natural repugnance between oil and spirit, as manifested in their unwilling amalgamation, is strong evidence against their friendly union by compulsion; therefore, to prevent serious eruptions, no more is used than the polish can conveniently neutralize. Rubber after rubber is applied with varied pressure, now lightly, now heavily, working in small circles, a beautiful dull smear following its course as the surface approaches to fulness; the rubber slightly biting, partly from the adhesive nature of the polish, but more from the partial vacuum produced by the flat rubber on the smooth surface of the wood. The pores being filled, and the work presenting a solid and compact body, it is set aside for some hours to settle and harden. In a day or two the polisher takes it up again, and although full when set aside, it is not so full now, having slightly sunk, and showing just a little of the pores.
With No. 0 paper he frees the surface of any slight imperfections that may appear, or if it is at all unsatisfactory or presents an uneven surface he cuts it down with glasspaper No. 1, in order that it may with this body be perfectly level and mirror-like. This done, ho proceeds as before to body-up the work, using great care in working it up to a point approaching a finish, full, clear, and hard; so that it shall require as little wetting as possible at the next, or finishing coat; which done he sets it aside again to harden.