Regulated pressure is applied to the air-tight material container, raising the coating material to the nozzle where only sufficient main-line pressure is used to lay the coating on. The spraying pressure necessarily depends on the density, consistency and viscosity of the material used.
[Ill.u.s.tration: Fig. 15. A one and one-half pint container and parts]
For fine finishing work, where the quant.i.ty of materials used each day is not great, or where the colors are changed frequently, the attached container type is recommended.
#40. Preparing Colors.#--The three primary colors are red, blue and yellow. With the three primary colors at hand, almost every variety of color desirable for ordinary use can be easily prepared. Fig. 17 shows a color chart.
Red mixed with yellow will result in orange.
Red mixed with blue will result in purple.
Yellow mixed with blue will result in green.
The colors obtained by mixing any two primaries are called secondary colors. Therefor the secondary colors are orange, purple and green.
Orange mixed with purple will result in brown.
Orange mixed with green will result in olive.
Purple mixed with green will result in slate.
The colors obtained by mixing any two secondaries are called tertiary colors.
The tertiary colors are brown, olive and slate.
Of course different tones of each color can be made up by mixing unequal proportions.
[Ill.u.s.tration: Fig. 16. Reducing outfit]
[Ill.u.s.tration: Fig. 17. Chart showing proportions required for standard colors]
CHAPTER III
COMMON WOODS USED IN TOY MAKING
#41. Economy in Selecting Material.#--Economic use of materials should be encouraged at all times. Toy making offers an excellent opportunity where economy may be taught in the most practical way.
Where toys are to be painted, more than one kind of wood may be used in the same toy and thereby using up small pieces of wood that would otherwise be called sc.r.a.p. Yet, it is not advisable to sacrifice the strength and durability of the whole toy for the sake of using up a piece of sc.r.a.p wood which weakens the particular part of the toy where it is used. For that, in the long run, is not economy.
#42. Qualities of Different Woods Used.#--The following are some of the common woods used in toy making.
Maple: hard, fine grained, compact, tough, used for wheels, axles, handles, dowel rods, etc.
Ash: white, strong, open grained, easily worked; used for bodies of coasters, wheels, axles, oars, etc.
Oak: hard, firm and compact, strong and durable, hard to work.
Birch: moderately hard and heavy, even grained; difficult to split, but easily worked.
Chestnut: resembles oak in appearance, is much softer, moderately hard, course grained, not strong, but durable.
Cypress: moderately hard, very fine and close grained, virtually indestructable; known as "the wood eternal".
Ba.s.swood: white, light, soft, tough, closed grained, easily worked, not strong, but durable; used for almost any part of a toy where much strength is not required.
White Pine: very light, soft, close and straight grained, inferior; easy to work.
Yellow Pine, yellowish, grain noticeable, harder than white pine, stronger.
Tulip (yellow poplar): light, soft, close and straight grained; tougher than many woods equally soft, compact, not very strong or durable, easily worked.
Spruce: straight growing, light, straight and even in grain, tough, elastic, easy to work.
CHAPTER IV
USE OF JIGS AND FIXTURES
#43. Value of Jigs and Fixtures.#--The use of jigs, fixtures, and other labor-saving devices is an important factor in ill.u.s.trating industrial and practical applications in the school shop. It is advisable to let each group of boys work out its own jig or fixture for the particular job they have on hand.
The three most common forms of jigs are cutting jigs, boring jigs, and a.s.sembling jigs. The important reasons for the use of such devices are: (1) They ill.u.s.trate the speed of output in shop work. (2) They give the student a good idea of machine operation. (3) They help in making the parts interchangeable. (4) They offer an opportunity for getting first hand information on cutting edge tools and their proper uses. (5) They show the boy the value of the use of jigs in factory work.
The toys ill.u.s.trated in this book have many simple operations, such as cutting stock to length, drilling holes, surfacing, etc., that can be easily done by the use of the proper fixtures.
For that reason toys are desirable projects to be made by the productive plan. Fig. 18 shows the use of a jig and the miter box.
#44. Cutting Small Wheels.#--A circle of the desired size wheel may be laid out on the wood with the aid of a compa.s.s, and cut in the outline with a coping saw or band saw. Of course, it would take quite a long time by this method to make the small wheels in large quant.i.ties and besides the result would not be as good as when the wheels are made by machine.
#45. Turning Wheels.#--Another way to produce wheels is to turn a cylinder to the required diameter, on the turning lathe. Then cut the cylinder on the circular saw into required thicknesses of wheels desired. This method is recommended for quick work.
[Ill.u.s.tration: Fig. 18. Production of toys by use of jigs]
If it is desired to round the end of wheels the operation can be done by leaving the cylinder in the lathe and applying the broad side of the skew chisel as shown in Fig. 33. The wheels may then be polished with a cloth after they have been sanded and while rotating in the lathe as shown in Fig. 34. In sanding, use first a fairly course grade of sandpaper, No. 1 or 1 and afterwards a fine grade, No. O or OO.
Before applying the cloth the wood may be varnished lightly while the lathe is not running, taking care to wipe off all the surplus varnish.
The varnish will a.s.sist in giving the surface a fine polish when the cloth is applied. For further explanations of the use of the turning lathe, see Sec. 55.
#46. Use of Wheel Cutter.#--Still another method of making small wheels is by use of the wheel cutter as shown in Fig. 19. This wheel cutter may be used in the ordinary bit brace. Good results may be obtained where the wheels are made out of thin, soft wood.
This wheel cutter is known on the market as a leather washer cutter. If one cannot be obtained it can easily be made in the school machine shop at a small cost. Fig. 20 shows a drawing of a wheel cutter.
You will notice that the blade can be adjusted to cut any diameter desired.
#47. Use of Coping Saw.#--Where a band saw is not included in the shop equipment, many articles such as animal forms and small wheels could very easily be cut out with a coping saw.