The vessel with the water is set into another containing boiling water, and heated; the soda is introduced gradually, and is soon dissolved, and the lac is then put in and stirred occasionally for about an hour, by which time the lac will be dissolved. The whole is then left for an hour or two, when it may be taken out and set to cool. It is better if allowed to remain a few days after having been made. When used, it is reduced to the required strength with more water, a hydrometer being employed as a test.
The bodies are simply immersed in the liquor, and passed between a pair of rollers one by one, thereby sweeping off the superfluous compound, but leaving them completely saturated. The hats with this stiffening must be immediately and rapidly dried in the stove.
This stiff is rendered the more popular by adding 3 oz. of common salt to the mixture before using it, as the salt neutralizes the soda, and the hats may be blocked immediately after being stiffened, thereby saving time and dispensing with the use of the stove.
The two following receipts are given as good and reliable English methods of stiffening hats:—
- 7 lbs. of orange shellac.
- 2 lbs. of gum sandarac.
- 4 ozs. gum mastic.
- ½ lb. of amber resin.
- 1 pint of solution of copal.
- 1 gallon of alcohol or of wood naphtha.
The lac, sandarac, mastic, and resin are dissolved in the spirit, and the solution of copal is added last.
This is called spirit proof, and like our own is put into the body with a stiff brush, and, being fully saturated, is set to dry.
A cheaper stiffening, also like our own called alkali or water stiffening, is—
- 7 lbs. of common black shellac.
- 1 lb. amber rosin.
- 4 ozs. gum thus.
- 4 ozs. gum mastic.
- 6 ozs. borax.
- ½ pint solution of copal.
The borax is first dissolved in 1 gallon of warm water.