Further to my instruction in L for Leather on the preparation of flour paste for laying leather and baize etc., I was recently looking for something unrelated in The Carriage Trimmers’ Manual (published in 1881) and came across a couple of snippets on the same topic.
WHEAT AND RYE FLOUR PASTES – HOW TO COOK – PREPARED PASTE FOR SUMMER USE
Trimmers’ paste requires to be smooth, elastic, free from moisture as possible, and possessed of great adhesive qualities. The materials used are wheat and rye flour. The paste of commerce is made of a very low grade of wheat flour, cooked by steam ; it is not a good article for trimmers, as it contains too much surplus moisture.
To make wheat paste select a low grade, but sweet wheat flour, and stir it into cold water until thoroughly dissolved ; then place the kettle [pail] over a quick fire and stir until it boils ; it should be allowed to cook five or six minutes after it is brought to a boil, and be well stirred while boiling and until it is cool ; if made in this way it will contain no surplus water and will be smooth and free from lumps.
For rye paste select good fine rye flour, place the necessary amount of water into a kettle over a quick fire, and when the water boils pour in the flour slowly, stirring it thoroughly ; continue to add flour until the desired thickness is obtained ; then allow it to boil about five minutes, after which remove it from the fire and continue to stir until boiling ceases, then cover and allow it to stand until it is cold. Rye flour paste made in this way is the smoothest, most adhesive and elastic paste in use. It is particularly valuable for pasting cloth on wood or leather.
The dry paste that gathers on the kettle should not be thrown away ; if it is soaked in cold water until it becomes soft, and again heated up to boiling heat, it is stronger and more elastic than when first made. Wheat or rye paste can be preserved from mold, etc., by adding a little carbolic acid or essential oil. The addition of a little dissolved gum Arabic adds materially to the adhesive qualities of flour paste.
To Make Paste.
To make the every-day paste for the trimming shop, where one or two trimmers are employed, have an iron pot, with a convenient handle, holding from two to three quarts ; put in nearly a quart of flour to make a pot full, stir enough water in to form a stiff dough, and with a paddle stir and beat until all the lumps have disappeared ; then stir in water gradually until it is reduced to the consistency of cream ; cook over a slow fire and stir continually, to prevent it sticking to the bottom ; do not remove it from the fire until all is well done. If these instructions are fully carried out the paste will be smooth and stiff ; be careful in mixing, for if once too thin the flour cannot be freed from lumps. Heavy paste is needed for leather and rough linings, where buckram is much used, while on some other places thinner paste will work ; heavy paste will not spread evenly on cloth, or on the muslin buggy tops, owing to the soft foundation.
Seasons have a great effect on paste ; in winter it may be made thin on account of its keeping sweet, while in summer it sours and becomes thin, and often worthless ; alum is a very good thing to put in paste in summer, and rosin is good the year round. The best flour does not make the best paste ; where flour is bolted fine the glutinous substance is nearly all abstracted, which destroys the adhesiveness of the paste ; coarser flour is the best.
The class of work requiring the best paste known to the craft, is glass frames and hammer cloths, which are exposed to the weather. To make a paste of that quality take rye flour, and to every quart of flour add a heaping tablespoonful of powdered rosin ; mix well together, then add water to make a stiff dough ; then thin to the consistency of very thick cream ; cook until well done over a slow fire ; stir all the time. Rye flour requires more cooking than wheat. A paste made this way has powers of resisting dampness that is not possessed by glue, and is very elastic ; it is the best paste known.