PAINTING MOUNTED FISHES.--A fish must be perfectly dry before it is touched with a brush. Time spent in painting a half-dry specimen is so much thrown away. The repairs with papier-mache must be complete and dry, and the specimen perfectly clean. Nearly every fish possesses in its coloring pigment a quality which imparts to it a silvery, metallic l.u.s.tre; therefore, to secure the finest result attainable in painting a fish, either an actual specimen or a plaster cast, all those that are silvery must first be coated over the entire scaly surface with nickel leaf, laid on sizing, similar to the treatment of gold leaf in gilding.
With dark-colored fishes satisfactory work may be done without the use of nickel leaf, except on the under parts, which are nearly always silvery white. It is absolutely impossible to reproduce the brilliant l.u.s.tre so characteristic of white scales by the use of white paint alone, or even silver bronze, or silver paint. Without the nickel underneath the paint looks dead and artificial. If you are called upon to make a large collection with as little outlay as possible, it will be sufficient to omit the nickel leaf, for your paint will still faithfully record the colors.
But if you wish to have your fish look as brilliantly beautiful as when taken struggling from the water, put on the leaf first, and paint on it, _thinly_, so that the silver will show through your colors and impart to them the desired l.u.s.tre. If you paint too thickly, the leaf will be covered up, and its l.u.s.tre obscured.
Do not attempt to use silver bronze, silver paint, or even silver leaf, for nickel leaf is the only substance which has sufficient l.u.s.tre _and will not oxidize_, and turn yellow.
If the whole body of a fish is dark, and without silvery tints, it is, of course, unnecessary to use leaf, for the l.u.s.tre can be obtained by varnishing over the paint.
In many fishes, such as the scaled carp, for example, Marsching"s gold paint or j.a.panese gold can be used directly on the scales (_after_ the entire fish has had a thin coat of Hendley"s enamel varnish), and the silver paint can be used to good effect in edging the scales. On the belly, however, which is silvery white, nickel leaf must be used. The heads of most fishes are so dark as to render the use of leaf unnecessary upon them, and of course it need not be used on the fins.
PAINTING PLASTER CASTS OF FISHES, REPTILES, ETC.--When a cast is first taken from the mould, it will nearly always be found that its surface is pitted here and there with little round holes caused by air-bubbles. The process of wetting the inside of these holes, and carefully filling each one with mixed plaster Paris is called "pointing up" a cast. After this has been carefully done, and the form and surface of the white cast is perfect, if the cast is thoroughly dry we are ready to begin to paint it, and proceed as described in the preceding section.
In case you find it impossible to use nickel leaf on your fishes, you can do very good work without it, except that the silvery parts will not be really silvery, and the white paint put on will gradually turn yellow with age. After you have given the specimen a good coat of colors (using zinc white for the silvery parts, because it is more permanent than other whites), varnish the specimen all over with a kind of heavy white varnish called Siccatif de Harlem, or, lacking that, enamel varnish. This will dry in about twenty minutes, after which paint the object over again, this time with extreme care in the final touches. In painting fishes and reptiles, there is a vast amount of detail to be wrought out, and constant blending of colors. On many fishes each scale must be marked off and painted separately. In blending the edges of two adjoining colors, it must be done with a clean brush--a small one, of course--with either a quick, nervous motion along the line of contact, or else a steady sweep, according to circ.u.mstances. When the brush gets full of paint, wash it out in benzine (_not_ turpentine), because it quickly becomes clean, and dries perfectly in a moment.
The eyes of fishes and reptiles are so peculiar, and vary so exceedingly, that it is a practical impossibility to provide gla.s.s eyes that will be exactly right for each species. For fishes, as good a way as any is to let the eye be cast _in situ_, and when you paint the fish, paint the eye also as it should be, and when dry, varnish it over with a thick coat of soluble gla.s.s or enamel varnish.
PART III.--MAKING CASTS.
CHAPTER x.x.xIV.
PRINCIPLES OF UNIVERSAL APPLICATION IN MAKING MOULDS AND CASTS.
The processes employed in making plaster Paris moulds and casts are very simple, and easily learned, even by one who has had no previous knowledge of the subject. To be sure, a certain degree of intelligence and skill is necessary in the operator; but we are not writing for the edification of duffers who do not know how to use their hands, or follow plain directions.
The first thing to understand is the difference between a mould that will "draw," and one that will not. A mould may be made on one side of a base-ball, and it will draw off the object at once, because there is no point on the ball behind which, or under which, the plaster can catch, and hang fast until something breaks. A mould of one full side of an apple will not draw, because the apple has a hollow at each end, and when these are set full of plaster the mould and the apple are held firmly together.
A hollow or a protuberance on an object which would prevent a mould from drawing away makes what is called an "undercut," and necessitates the making of a separate piece in the mould. To cast several copies of a human head and neck necessitates the making of a mould in several pieces, all fitting very nicely together, with countersink joints, to accommodate the undercuts behind the ears, under the chin, the hollows of the eyes, etc.
A mould made in more than two pieces is called a "piece mould." It may have any number of pieces, of course, according to the nature of the object.
Perhaps the most remarkable piece mould in existence is that used by Professor H.A. Ward in making casts of the tail of the great fossil armadillo called the glyptodon. The tail is a ma.s.s of big conical tubercles, and the mould contains, as nearly as I can remember, about one hundred and twenty-five pieces, all fitting into a big "jacket" of plaster which holds them all in place while a cast is being made. In the case of a piece mould the cast is not taken out of the mould, but the latter is dissected and taken off the cast, piece by piece.
The principles involved in making moulds and casts are best explained by brief descriptions of the processes, and if they are learned by carefully following the directions here given, the operator will be able to apply them, indefinitely, to all cla.s.ses of objects, large or small.
HOW TO MAKE A PIECE MOULD.--Let us take a good-sized apple as our subject, and follow out the process, step by step.
1. In making a mould of any kind of fruit, first soak the fruit in water an hour or two, to "plump it up," so that it will not swell in the mould and cause trouble.
2. Wipe it dry, and with a small paint-brush give it a thin coat of lard oil, so that the plaster will not stick to it. Some objects should be coated with clay water, or very thin clay, instead of oil.
[Ill.u.s.tration: FIG. 59.--Beginning to Make a Piece Mould.]
3. Bed one end of the apple in damp sand, precisely as shown in the ill.u.s.tration (Fig. 59). If you have no sand, use fine sawdust, or wet corn meal. Some objects require clay. Do not have the sand wet and water soaked, for it will not yield so readily to the palette knife.
4. Dot a line on the sand all round, to show how far out to run the plaster, and avoid making the mould too thick.
5. Take two-thirds of a teacup of water, and put in plaster Paris until it becomes about as thick as New Orleans mola.s.ses. Stir thoroughly with a spoon, and let it stand two or three minutes.
6. Dip the plaster out with a teaspoon, and cover the exposed part of the apple. It will run down all over the horizontal surface of the sand, but never mind that. Make it cover the apple everywhere to a depth of a quarter of an inch. In some places it will be thicker. After about three or four minutes the plaster will be as stiff as modeling clay. While it is in this state take your palette knife and neatly smooth and shape the outer surface. Finish smoothing with the finger, and let the plaster harden. This will take about seven minutes longer, or until the plaster has warmed and cooled again. The time varies according to the humidity of the atmosphere.
7. Take the apple from the sand, with the half mould on it, wash off the sand, and neatly trim the edge of the mould with a knife.
8. With a blunt-pointed knife make three countersunk holes in the edge of the mould.
9. With a brush, anoint the edge of the mould with thin clay, clay-water, or soft soap, or lard oil, or even lard.
[Ill.u.s.tration: FIG. 60.--Second Step in Making a Piece Mould.]
10. Turn the mould up on edge, and bed half of the exposed portion of the apple in the sand, as seen in Fig. 60. Fill in this s.p.a.ce with plaster, precisely the same as when the first piece was made, which produces the second piece of the mould.
11. Make the countersunk holes in the edge of the second piece as before; fill in with plaster all the remaining s.p.a.ce between pieces 1 and 2, and we have the third piece, which completes the mould. As soon as this hardens, tap the mould lightly all over with a small mallet, to loosen it from the object, then take out piece No. 3, and the mould is easily separated and the apple taken out. Take one part of gum sandarac (dissolved in ninety-five per cent alcohol) and three parts of white sh.e.l.lac, also dissolved, and mix them. They will form a solution a little thicker than water. Have the mould perfectly dry, and apply this solution to the entire inner surface of it with a small paint-brush. The solution will be absorbed at first, and you must continue to apply it until the inner surface has an egg-sh.e.l.l gloss, which is sufficient. Then oil the inside with lard oil.
[Ill.u.s.tration: FIG. 61.--Last Step in Making a Piece Mould.]
[Ill.u.s.tration: FIG. 62.--The Finished Mould.]
12. Put together pieces 1 and 2 of the mould, cut a groove around them to hold a stout string, and tie it tightly to hold them together. Then mix some plaster, and fill each piece (1 and 2) about half full, walling it up the sides with the finger, a quarter of an inch thick, or as the plaster will make it. Then wipe off the exposed edges of the mould so they will fit snugly together with No. 3. Now mix up a little more plaster, about one-fourth the quant.i.ty first used, pour into the hollow, then put on the third piece; tie all tightly together, and turn the mould round and round slowly. This fills the third piece, and holds it in its place. Keep turning the mould slowly, and tapping it with the left hand. Leave a little of the plaster on the outside, on a piece of gla.s.s or paper, so that you can tell when it gets hard and flinty in the mould. Do not take off the mould until the cast is perfectly hard.
HOW TO MAKE A WASTE MOULD.--When a soft or fleshy object is to be cast, one which will yield, and draw out of the mould regardless of undercuts, a very quick and satisfactory process (provided a second copy of the cast will never be wanted) is to make what is called a waste mould. This, with a fleshy subject, is a short cut to a perfect cast, and often saves hours of valuable time. In obtaining casts of mammal heads, legs, or other parts, or casts of fishes and reptiles, it is the method _par excellence_. Let us learn the principles of it by making a waste mould and cast of a human hand.
1. Bed the hand in damp sand (_i.e._, one-half of it), as shown in the accompanying figure, No. 63.
[Ill.u.s.tration: FIG. 63.--The Beginning of a Waste Mould.]
2. Give the exposed portion of the hand a good coat of lard oil.
3. Take two-thirds of a gill of water in a teacup, put into it half a teaspoonful of dry Indian red (to be bought for five cents at any paint store), and mix it up. This is to color some plaster with which to make a thin, colored lining for our mould, the purpose of which will be appreciated later on.
4. Mix with this red water one and one-half gills of plaster Paris, stir it up thoroughly to get it well mixed and free from air-bubbles, then with a teaspoon distribute it all over the hand until it is completely covered with a coat of the pink plaster about one-eighth of an inch thick.
5. After this thin coat has hardened, anoint the surface of it with lard oil or clay water, so that the plaster which is to be put upon it will not stick to it, but separate readily when the outer case of the mould is chiseled off.
6. Take one and one-half gills of water, and three-quarters of a pint of plaster, mix for outer case of mould, and apply on top of the pink lining to a thickness of about half an inch. Let this get perfectly hard. (Fig.
64.)
[Ill.u.s.tration: FIG. 64.--Second Step in Making a Waste Mould.]
7. Take the subject out of the sand. Turn it over, anoint the edge of the mould with clay water or lard oil, and treat the other side in precisely the same manner. This is the course when the whole object is to be cast. If half the object is sufficient, as is the case in taking a record cast of one side of an animal"s head and body, then take the subject from the mould, and
8. Wash the inside of the mould thoroughly to get out the clay and sand.
9. Anoint the inside of the mould with clay water, thin clay, or lard oil, and lay it in position to receive the plaster.