C. C. Bosworth

Every pattern-maker with any regard for his reputation loves to see the object of his skill leave his hands with a luster and without a scratch or blemish, and what is his consternation to see the molder, when he receives the same piece of work, take sandpaper, and that not always the finest grade, and go over this artistic piece of work to his own satisfaction.

We learn from this that those who use the patterns look upon the finish from another point of view, viz., that of utility instead or appearance, which is, after all the right view. Yet, at the same time, I do not wish to discourage any one in his efforts to produce a nice looking pattern. I wish only to show that it is a matter of secondary importance, the first being that of a hard, smooth, impervious coating which will leave the sand with little resistance and wear well. The ordinary orange or yellow shellac, which is best flake shellac dissolved in eithergrain or wood alcohol (but never in a mixture of the two), seems to be generally accepted as the most satisfactory varnish for a pattern, filling, as it does, the requirements named.

The ready-made shellac varnish varies In quality. The writer has known it to be of such a nature as to be apparently dry, and at the same time when put in the sand, the latter would adhere to the pattern to the extent of making it impossible to use, and no length of time in drying seemed to help the cause, and hence this varnish had all to be scraped off. Then again in making colored varnishes one must be careful in the selection of the coioringpowders; for instance, in making black varnish, which is simply the yellow made black by the addition of lampblack, some grades of which when rubbed between the fingers are smooth and velvety to the touch, while other grades are gritty, and this latter will give a very unsatisfactory surface, with the best of care, and has but little gloss. Varnish, as its name implies, is a resinous liquid, laid on work to give it a gloss, but this gloss to a great extent is dependent upon the under coating and then upon the body and composition of the liquid. The under surface must be hard and smooth. We are all acquainted with the fact that the first coat of shellac laid upon the pattern gives it no luster at all, and this is even true of the second coat if the varnish used is very thin; it is absorbed by the grain of the wood which swells and raises its fiber, giving a rough dull surface, but after the pores of the wood become filled by the successive coats, each coat being rubbed lightly to a smooth finish with worn and fine sand paper, we notice that the succeeding coats become more glossy. When his varnish is thinned out too much it is possible to get but little gloss, as there is not enough of the resinous composition left on the surface, after the alcohol has evaporated, to give it a sufficient new body.

And again, if varnish is too thick there is not enough of the alcohol to float the resinous component, hence it cannot spread itself out evenly on the surface, hence it will appear mottled and when dry will even feel uneven, though glossy. When in this condition it is hard even to rub it to a smooth finish, in fact, it is worse to use varnish too thick than too thin. When a pattern is varnished often with shellac which is too thick it will crack and come off in flakes, bringing off all the successive coatings down to the wood, which makes the pattern hard to draw, and it has to be scraped; therefore, if the pattern maker would be careful in the selection of his materials, obtain a good surface and a medium body to his varnish, he will have all the gloss he desires after the third or fourth coat.

Now, in obtaining a good hard surface, I have known patterns that were to have constant use to be given a first coat or two of lead and oil for a filler; this gives a surface as hard and smooth as stone.

I have also known copal varnish, the outside kind, sometimes known as spar varnish, to be used where a specially glossy finish was wanted. Of course it must be applied to a good, dry, hard surface, and it takes several days for each coat of copal varnish to dry, but it wears well.

Oxalic acid is sometimes used to clear varnish. A teaspoonful will clear a quart of muddy varnish and give it a good clear color, but I do not like to use it as it is very poisonous. The writer once saw a man who nearly lost his arm by its use. He had a cut on his hand and got some acid treated varnish on it, the result being blood poisoning, much pain, and nearly the loss of his arm.

In fact, any shellac varnish should not be used on a cut, as is often done, as it it well known that wood alcohol is a poison of itself.

To keep varnish clear, I prefer keeping it in a porcelain cup or crock, well covered. Do not keep shellac varnish of any color, even black, in a galvanized can; it ruins the varnish.

As to pigment for red varnish, I find that indian red answers the purpose well, though of course it is not quite so brilliant as vermilion. - "The Patternmaker. "