The proper kinds of brushes can be obtained of any brush dealer. For ordinary work, a ¾ long No. 5 brush will answer, the cost being about 20 cents. Purchase a set of about six assorted sizes, which will answer for all work.
Use great care in selecting your brushes. See that the hairs are of an equal length and that the ends are even when the brush is flattened.
Train your brushes flat by always using the same two sides. Rinse them in a glass of clean water after each using, and give them a thorough cleansing—with soap and water about twice a week. This will keep them in good condition.
Figure 3 shows the exact sizes of a set of brushes, which will answer for all purposes.
CARDBOARD.
Your own judgment should be sufficient to know good cardboard. The more you pay the better goods you get, that is, if you deal with a reputable house.
Use a pure white, heavy coated board from 6 to 10 ply, according to the size of the sign you are making. See that your board is of sufficient thickness to prevent warping. If you use frames, of course your board need not be so heavy.
Colored card-boards are well enough, occasionally, but as a rule use plain white; people do not tire of it so easily.