Reference tables are very convenient to use but soon get dirty and torn. To prevent this pour some lacquer in a shallow tray and dip the paper into it and hang it up to drain and dry. This not only makes the paper dirt-proof but toughens it as well. Milton Burgess.
Tracings that have become badly soiled from handling or other causes, may be easily cleaned by thoroughly sponging the cloth with benzine or gasoline. Kerosene will serve the purpose, but it is not so good. It does not injure the cloth in the least, but on the other hand has the effect of re-establishing the color of a much used tracing, and will remove pencil marks perfectly. When some compound has been used on the tracing to remove the ink lines, leaving a sticky and gummy surface, benzine will quickly clean and dry the affected portion, so that it can be worked over again. T. E. O'Donnell.
Mix thoroughly one pound of pulverized chalk with one-quarter pound of borax. Rub some of this mixture into a chamois skin, and rub the tracing carefully with this. This preparation is superior to pure chalk. Rex McKee.
When it is required to color or to write with color on a drawing or blue-print which has to be varnished later, mix a little isinglass with the color; this will prevent the color running when the size is applied.
Manchester, Eng. H. T. Millar.
Place sheets of blotting paper over and under the stained page, to protect the others. Lay powdered magnesia on the stain and under it; then press over the blotting paper with a hot iron. When the powder is shaken off, the stain is gone.
New Britain, Conn. F. L. Engel.
To write on triangles or other instruments made of celluloid use anhydrous acetic acid. The writing will appear dull on the glossy surface. If colored writing is desired, add some coloring matter to the acid. J. M. Menegus.
Los Angeles, Cal.
It is a well-known fact that neither the glossy nor the dull side of tracing cloth takes ink readily without being prepared in some manner. The usual way is to sprinkle powdered soapstone or chalk on the tracing cloth and rub it over the surface with a piece of cloth. This helps somewhat, but not enough to be perfectly satisfactory. After trying various methods, I have found a way which gives excellent results, and that is, to sprinkle the powdered soapstone on the cloth as usual, but rub it in with a blotter instead of a piece of cloth, using a circular motion and considerable pressure; of course It is necessary to brush away the superfluous powder. The use of a blotter has an abraiding effect and it is just harsh enough to give the cloth a surface which will take the ink readily and still leave the pens unharmed. I find it to be an advantage to repeat this process each morning in case the tracing is not finished the day it is started; the rubbing of the blotter over the lines already inked in does absolutely no harm and if anything makes the lines more dense. A trial of this method will convince the draftsman that the cloth will take the ink better than by any other method. Chicago, Ill. Robert A. Lachmann.
A great many of our railroads and large manufacturing concerns throughout the country are using small printing presses, for the purpose of putting titles on their drawings. It is titles put on in this manner with tracing cloth printing ink to which I refer. After the title has been printed on the drawing, lacquer it over with a very thin coat of French varnish (such as is used by artists). This can be best applied with a chisel-shaped camel's hair brush, equal in width to the height of the letters in the title. A good substitute where French varnish cannot be obtained is made by cutting ¼ ounce of the best grade of white shellac in ½ pint of alcohol. As both of these varnishes dry very quickly, the tracings may be used soon after the titles are put on. E. W. Bowen.