Mix the flour well with a little cold water, beating until perfectly smooth. Add the alum dissolved in a little cold water. Pour on two cups of the boiling water, strain through a wire sieve. Add the remainder of the boiling water and cook, stirring constantly until partially clear. Add the oil of clove and put into a clean, covered earthen jar. The paste thickens as it cools. Take out small quantities for use. The materials for this paste cost less than 2 cents for a hundred books.
To all pastes it is best to add a spoonful of carbolic acid or formaldehyde to prevent spoiling. A small quantity of corrosive sublimate will make paste unattractive to bugs.
Although home-made pastes are cheapest, they are a bother to make and the saving of expense over commercial pastes is not worth while except in the very small library. Besides paste in bulk which can be obtained from the local binder there are many kinds of commercial paste. Some may be bought in powders; others, designed primarily for mounting photographs, in glass jars; still others in cans ready to use. The powders are cheap, keep indefinitely, but when needed must be mixed with water, and as a rule are not very satisfactory. Higgins' and other photo-mounting pastes are expensive and dry too quickly, but keep indefinitely. In the long run the most satisfactory pastes are those in tin cans with tight lids; these are ready to use, do not dry up and the preservative which they contain keeps them indefinitely. The Arabol Manufacturing Company, 100 William Street, New York, makes several varieties. Their "Sphinx" paste, which gives excellent satisfaction, can be bought in six one-gallon can lots at 75 cents a gallon, f. o. b., and in larger quantities at slightly reduced rates. Great care should be used to avoid having the paste so thin that it makes the paper stretch.
Although paste is a necessity in every library, there is a tendency to use too much of it, and to use it when it is not necessary. Ordinarily it will injure the book less than other adhesives, but it should be used sparingly on books that must be rebound. When applied to the backs of loose signatures they become brittle; then when the book goes to the bindery a much larger amount must be cut from the back than would otherwise be the case.
If paste is to be applied to part of the paper only, the easiest way is to lay the paper on a board, place another piece of paper over it, leaving exposed the surface to which paste is to be applied. It can be spread more evenly with the finger, faster with a soft, long-handled brush. The larger libraries will find a pasting-machine a great time-saver. Book labels, book pockets, new end papers to freshen soiled books—anything which needs to have the entire surface covered—is pasted on the machine in one-tenth the time required by hand.
Glue. For ordinary mending, glue should never be used. (See Materials, [p. 82.]) Flexible glue, however, is a necessity for recasing and recovering books. It keeps indefinitely, can be used easily by those who acquire the knack of using it, and it sticks everlastingly.
Mucilage. Mucilage has no real place in a library. If paste is not the suitable material to use, substitute flexible glue, never mucilage.
Cheesecloth. This well-known cloth is used when pressing down paper or book labels after they have been pasted and applied, and for quickly cleaning the hands of superfluous paste or glue. It should be cut in pieces of convenient size and not used many times before being discarded.
Jaconet. A thin, strong muslin will be needed for guarding sections and occasionally for forming joints. Jaconet is the best and may be obtained from a few library binders.