The softest woods should be chosen for veneering upon, - such as common cedar or yellow pine. Perhaps the best of all for the purpose is "arrow board," twelve foot lengths of which can be had of perfectly straight grain, and without a knot. Of course no one ever veneers over a knot. Hard wood can be veneered, - boxwood with ivory,for instance; but wood that will warp and twist, such as nasty cross-grained mahogany, must be avoided.
The veneer, and the wood on which it is to be laid, must both be carefully prepared, the former by taking out all marks of the saw on both sides with a fine toothing plane, the latter with a coarser toothing plane. If the veneer happens to be broken in doing this, it may be repaired at once with a bit of stiff paper glued upon it on the upper side. The veneer should be cut rather larger than the surface to be covered; if much twisted it may be damped and placed under a board and weight over night. This saves much trouble; but veneers are so cheap - about two cents a foot - that it is not worth while taking much trouble about refractory pieces. The wood to be veneered must now be sized with thin glue: the ordinary glue-pot will supply this by dipping the brush first into the glue, then into the boiling water in the outer vessel. This size must be allowed to dry before the veneer is laid.
We will suppose now that the veneering process is about to commence. The glue in good condition, and boiling hot, the bench cleared, a basin of hot water with the veneering hammer and a sponge in it, a cloth or two, and everything in such position that one will not interfere with or be in the way of another.
First, damp with hot water that side of the veneer which is not to be glued, then glue the other side. Second, glue over as quickly as possible the wood itself, previously toothed and sized. Third, bring the veneer rapidly to it, pressing it down with the outspread hands, taking care that the edges of the veneer overlay a little all round. Fourth, grasp the veneering hammer close to the pane (shaking off the hot water from it) and the handle pointing away from you; wriggle it about, pressing down tightly, and squeezing the glue from the center out at the edges. If it is a large piece of stuff which is to be veneered, the assistance of a hot flatiron from the kitchen will be wanted to make the glue liquid again after it has set; but don't let it dry the wood underneath it, or it will burn the wood and scorch the veneer, and ruin the work. Fifth, having got out all the glue possible, search the surface for blisters, which will at once be betrayed by the sound they give when tapped with the handle of the hammer; the hot iron (or the inner vessel of the glue-pot itself, which often answers the purpose) must be applied, and the process with the hammer repeated.
When the hammer is not in the hand it should be in the hot water.
The whole may now be sponged over with hot water, and wiped as dry as can be. And observe throughout the above process never have any slop and wet about the work that you can avoid. Whenever you use the sponge, squeeze it well first. Damp and heat is wanted, not wet and heat. It is a good thing to have the sponge in the left hand nearly all the time, ready to take up any moisture or squeezed-out glue from the front of the hammer.
So much for laying veneers with the hammer, which, though a valuable tool for the amateur, is not much used in the best cabinet-makers' shops. Cauls are adopted instead. They are made of wood, the shape and size of the surface to be veneered; or, better still, of rolled zinc plate, and being made very hot before a good blaze of shavings, they are clamped down on the work when the veneer is got into its place. They must be previously soaped to prevent them sticking to the veneer. The whole is then left to dry together.
The hammer is quite sufficient for most amateurs. I have laid veneers with it five feet long by eighteen inches wide without assistance, and without leaving a blister. Cauls, however, are very necessary if a double curved surface has to be veneered, or a concave surface: they need not be used for a simple convex surface. By wetting well one side of the veneer it will curl up, and can easily be laid on such a surface; but it will be well to bind the whole round with some soft string to assist in keeping it down while drying.