Sea Green 3/8 oz. lamp black oz. medium chrome green 1 oz. medium chrome yellow
Where tinting colors are used in sufficiently large quant.i.ties to alter the consistency of the paint, add one-half as much linseed oil and turpentine, by weight, as you add tinting material.
#29. Enameling.#--When using enamel as a finish for toys, care should be taken that the surface of the toy is in proper condition. To obtain good results proceed as follows: Give the wood a coat of sh.e.l.lac. Sand lightly and dust. The following coat should consist of part of white paint and one part of the enamel to be used. This coat should be slightly tinted with the finishing color, if the finishing coat is not white. Allow twenty-four hours for drying thoroly; then sand with No. OO sand paper. Next apply a coat of enamel of the color desired for the finished work. (Enamels may be tinted with colors ground in oil.)
Should the enamel not work freely, add a spoonful of benzine to a gallon of enamel. Turpentine may also be used as a thinner for enamel.
A better finish of enamel consists of two coats of paint before applying the enamel. This gives it a stronger body and of course makes it more durable.
Because of its durability and for sanitary reasons enamel is the most desirable finish for toys. Its glossy finish is attractive and very appealing to children.
#30. The Dipping Method.#--When a considerable quant.i.ty of toys is to be finished, the problem to be faced will be the cost of application of the paint rather than the cost of the paint itself. The dipping process, (immersing the material to be covered) is found to be the most successful, especially in toy making, where so many small parts are used.
Many of the small pieces made can be subjected to the dipping process at quite a saving of time and labor, with probably better results than where the application of paint or stain is done with a brush.
The success of the dipping process depends on the arrangement adopted for holding the toys while the actual dipping is done and while they are drying. Here the exercise of a little ingenuity on the part of the students and teacher, will overcome most difficulties.
Supposing that a number of checkers, or handles, or small wheels are to be stained. A dipping frame as shown in Fig. 8 could very easily be prepared. You will notice the screen tray (which is removable), and the tin sheet which slopes towards the container. The small pieces to be stained can be handled in wire baskets with mesh just small enough so that the pieces will not fall thru.
The wire basket is then immersed in the container and worked up and down, so that the liquid will penetrate and touch all pieces. It is then pulled up and swung over the screen tray, where the contents of the wire basket is dumped. Here, the superfluous paint will drip off on the tin sheet, which, because of its slope, will cause the superfluous paint to flow back in to the container. Fig. 9 shows the dipping frame in use.
The screen tray can be removed and placed in a rack to allow for further drying. Several trays could then be made and a rack to hold them could very easily be constructed.
The paint used for dipping purposes must so be prepared that too much does not run off or too much stay on, for this is surely one way to spoil the work. It should be thinned to the right consistency and care should be taken that the thinners used are of the best quality.
Where larger pieces of work are to be dipped, wire attachments could be devised and each part hung separately over the dipping frame until ready to be placed in a rack. If the wire attachment forms a hook on one end, it will be possible to hang up the toy until drained and dried. In removing the toy from the paint it should be drawn out very slowly so that the surface of the paint may be left as smooth as possible.
Where one desires line effects on toys, these may be lined in afterwards with a small size striping brush or sign painter"s pencil.
[Ill.u.s.tration: Fig. 8. Dipping frame]
[Ill.u.s.tration: Fig. 9. Using the dipping frame]
#31. Polishing by Tumbling.#---Excellent results in polishing large quant.i.ties of small pieces, may be obtained by tumbling. The material to be polished should be thoroly dry. The parts are then placed in a tumbler as shown in Fig. 10. Cut up paraffine wax into small pieces, using about one-fourth pound to each tumbler full of toys. Allow these to tumble several hours. This will distribute the wax evenly over the parts and produce a polished surface.
The tumbler as shown in Fig. 10 is turned by hand, altho it could very easily be placed in a lathe, where one is available.
#32. Care of Brushes.#--A suitable place should be provided for brushes that are not in use. A tin-lined keeper is recommended. Brushes should be suspended so that their bristles will not touch the bottom of the keeper, and have the liquid in which they are kept come well up over the bristles, so that none of the paint or varnish may dry in the b.u.t.t of the brush.
#33. Paint Application by Means of Compressed Air.#--In recent years, great advancement has been made in the application of paint by means of compressed air. The early use of pneumatic painting equipment was confined almost exclusively to the application of finishing materials such as j.a.pans, enamels, lacquers, varnishes, etc., on manufactured products. But in the past few years improvements have been made which eliminate all of the difficulties originally experienced and make possible the use of this method for interior and exterior painting, such as buildings, ships, etc.; and at present, a large portion of factory maintenance work is done in this manner. Excessive fumes have been eliminated and all materials can be applied without removing the volatile thinners, solvents, binders, etc., thru air reduction. This is brought about thru the use of low pressure and the perfection of ingenious patent nozzles and other improvements.
[Ill.u.s.tration: Fig. 10. Tumbler for polishing small pieces]
#34. Uses of Pneumatic Sprayers.#--Pneumatic paint sprayers, or air brushes, are extensively used in the manufacture of toys, furniture, automobile bodies, sewing machines, telephones, electrical equipment; in fact, very nearly all manufactured products, as well as on ships, structural steel and iron work, bridges and buildings.
The speed of the air brush is very great compared with hand-brush work.
Usually, an air-brush operator will accomplish as much in one hour as a hand or bristle-brush worker will in one day; and it is possible to obtain an even coating, free from sags, runs or brush-marks and better results are obtained than with the hand brush method. A film of paint can be applied in one operation equal to two hand-brush coats, as it is not necessary to reduce paints by thinning as much for air brush application, in a great many instances, as is the usual practice for hand-brushing. The air sprayer can also reach places inaccessible to the hand brush, and a perfect coat can be applied over rough, uneven surfaces, which could not be obtained by hand-brushing.
In considering pneumatic painting equipment, the most important thing to be kept in mind is the proper application of materials. This can be successfully accomplished only thru the use of compressed air at low pressures. By this is meant using only sufficient main-line air to lay the paint, enamel, varnish or whatever finish may be used, on the object. Excessive pressure results in fumes, waste of material and air reduction taking place. By air reduction is meant the removal of the more volatile solvents, thinners, binders, etc., thru evaporation, and the material thus loses its adherent and coherent properties.
Both types of air-brush equipment ill.u.s.trated here require three cubic feet of air per minute to operate and the pressure necessary depends on the density, consistency or viscosity of the material used. For example, undercoaters, j.a.pans, etc.; require from twelve to fifteen pounds of pressure to apply perfectly; while enamels and varnishes take from eighteen to twenty-five pounds. Water stains require about five pounds of pressure.
#35. Construction of Pneumatic Painting Outfit.#--A pneumatic painting outfit for finishing work consists essentially of an air brush, either of the attached-container type or the gun-type with separate paint tank, and a small compressor of sufficient capacity to operate the air brush, which can be belt-driven from shafting or direct connected. An exhaust hood with fan, for the removal of fumes, is advisable where the operation is reasonably continuous and especially where lacquers are used. The paint, ready for application, is poured into the tank; and the compressed air line leads to the tank with a branch line for air and paint from the tank to the nozzle of the gun type of machine; while only the air line is required with the attached-container type.
The air hose used is 5/16" in diameter while the paint or fluid hose is the same size. The paint hose is made of a special compound to resist the action of the thinners, solvents, etc., used in the paint; and it is important to have this correct, so that the lining will not disintegrate and clog the air brush or gun.
Fig. 11 shows a five-gallon container type. It will be noticed that the fluid connection is nearest the nozzle and that the air connection is at the bottom of the grip.
#36. Special Attachments for Different Surfaces.#--A cone nozzle is furnished for painting irregular surfaces and a fan nozzle for wide, flat work. Adjusting and locking the nozzle regulates the degree of atomization. The jets of the fan nozzle are depressed to prevent being knocked out of alignment. Final regulation of the flow of material is made on the back of the gun, independent of the pressure on the material container. A wide variety of adjustment is possible with this positive regulation.
The first pull on the trigger gives air only, which can be used for dusting ahead of the work; and as the trigger is released, the air valve closes last, which prevents clogging and dripping. When adjustments have been made the trigger action is the only moving part of the machine.
Figs. 12 and 13 show the five-gallon container type in actual use.
#37. Cleaning Pneumatic Machines.#--It is not necessary to take the gun apart nor disconnect the hose to clean the machine. Thinner can be run thru the device without loss by placing a small can of reducer of the last material used in the machine, and forcing it thru in the usual manner.
[Ill.u.s.tration: Fig. 11. A five-gallon air brush outfit]
#38. Directions for Cleaning Machine.#--Close right-hand Air Valve and open release valve. Unscrew air nozzle a few turns. Obstruct outlet with thumb and pull trigger. Spraying pressure is thus forced thru gun and fluid hose and the material backed into the container. It is advisable frequently to run thinner thru the machine as follows: (1) Place small can of thinner in center of container directly beneath fluid tube. (2) Replace cover and tighten wing-nuts. (3) Close left-hand air valve and open right-hand air valve. Pressure on container will force thinner thru the machine and clean perfectly without loss. Do not use spraying pressure in cleaning. The thinner can be used again for either cleaning or thinning purposes.
[Ill.u.s.tration: Fig. 12. Using pneumatic paint sprayers]
#39. Directions for Operating Pneumatic Equipment.#--
1. Attach main-line air hose to air filter.
2. Attach fluid hose to connection marked "Fluid" on tank and to the front connection near air nozzle on hand-piece.
[Ill.u.s.tration: Fig. 13. A five-gallon outfit in actual use]
3. Attach air hose to connection marked "Air" on cover and to the handle connection on hand-piece.
4. Thoroly mix and strain material so that it is entirely free from skins, lumps, and foreign materials.
5. Tighten wing-nuts until paint container is air-tight.
6. See that release valve is closed. Then open right-hand air valve, turn fluid-pressure regulator until gage shows 5 lbs. pressure in container. Pull trigger and use fluid regulator on gun to control the flow. If material is heavy, increase pressure in container.
[Ill.u.s.tration: Fig. 14. Attached container type of sprayer]
7. Open left-hand air valve and turn spraying pressure regulator until sufficient pressure (5 lbs. to 25 lbs.), is obtained to lay the material on.
8. Make final adjustment of the flow of material with fluid regulator on back of hand-piece and get proper spray by adjusting the air nozzle.
9. Spraying pressure and pressure in the container depends upon the density of the material used and the size of the surface to be coated. A little experimenting on the part of the operator will determine the best pressure to use. When the fan nozzle is used, 3 to 5 lbs. more pressure should be applied to the material container and from 5 to 8 lbs. more atomizing or spraying pressure used.
Fig. 14 shows a complete attached container which operates on identically the same principles as the type shown in Fig. 11. It consists of a 1 pint container, reducing outfit, compressor, and air tank. The 1 pint container as shown in Fig. 15 is supplied complete with two fluid tips, gasket, agitator tube, cup-holder, hose union, and six feet of air hose.
The reducing outfit in Fig. 16 consists of a regulative valve, an air gage, and an air filter, complete with connections and fittings. This outfit is for the purpose of maintaining an even low spraying pressure.