The building in which varnish is made ought to be quite detached from any other building whatever, and have a door-way in the centre with folding doors made to lift off the hinges. Let the roof of the building slope to the front; fix also in each end wall a frame and door made to lift off the hinges, so that, when necessary, there may be a free draught through the premises. Let three skylights be made and fixed in the roof, not directly over the furnaces, but on one side, so as to throw light on the furnaces. The skylights and flaps must be well secured by lead flushings, to prevent wet getting in, which might be attended with serious consequences. In the left-hand corner, against the back wall, dig out a foundation and fix over a furnace the set pot, used for boiling oil, gold size, japan, and Brunswick black. Dig out a foundation facing the front door against the back wall for the boiling furnace, Fig. 1; against the back wall, in the right-hand corner, dig out a foundation for the gum furnace, Figs. 2 and 3; this and all the other furnaces require to have slow fires kept in them for a day, in order to dry them slowly, and prevent their cracking.
Gum pot - Procure a copper gum pot to fit into the last furnace, Fig. 3. The bottom a, Fig. 3, is hammered out of a solid block of copper, and fashioned, all of one piece, exactly like a hat without the brim. The upper part of the pot b, is made of sheet copper, of a cylindrical form, 10 in. diameter at the top, and 2 ft. 2 in. high, about 3/8 in. thick; the lower part of the cylinder is then riveted to the bottom with copper rivets, the heads of which are inside, and project through the lappings of the copper, flattened on both sides. Previous to riveting on the bottom, a flange of copper, of about 3/8 in. in thickness, is fixed on to the bottom part, under the large rivets: it is fixed horizontally round the pot. Also previous to riveting on the bottom, put on the iron hoop d, 1 1/2 in. in breadth, to which is welded an iron handle, made 1 in. broad by 1 in. thick, gradually increasing to 2 in. in breadth, but decreasing in thickness. The length from pot to handle end, 2 ft. 8 in.
Procure a copper pot e to fit furnace, Fig. 7, the bottom to be beat out of the solid, as the gum pot, and of the following dimensions: Diameter across the bottom outside, 20 in.; height of bottom, 7 in.; the cylindrical or body part of the pot to be 2 ft. 10 in. in depth, and joined to the bottom part with strong copper rivets, made to project through at least three-quarters of an inch, and to be well hammered inside and out; for, as there is no flange, the rivets must be large and strong, to support the weight of the pot and its contents while boiling on the furnace plate. It ought to fit the plate neatly, yet so easy as to lift off freely. Seven inches below the mouth of the pot fix on two strong iron handles, one on each side, riveted through each end with two strong rivets; the space for the hands to be 7 in., and 1 1/2 in. in diameter, and to project 4 in. from the pot sides.
In addition to the furnaces the varnish manufacturer requires two copper ladles, made to hold two quarts each, with turned hardwood handles. Two good ladles for the iron set pot, made of sheet copper or sheet iron, with ash handles. For a pot of 40 gallons, or upwards, the ladle to hold 3 quarts. Two copper stirrers, Fig. 4, made from three-quarter diameter cop-per rods 3 1/2 ft. long, beat flat at the one end to 1 1/2 in. breadth, 8 in. up the rod; to be finished with ferruled handles 7 in. in length. One large, strong, copper funnel, with lapped seams, for straining boiling varnish or oil; tin or soldered funnels would melt. One copper oil-jack, Kig. 5,which will contain 2 gallons, for pouring in hot or boiling oil, with a large strong pitcher handle, and spout in front. One brass or copper sieve containing 6Q meshes to the inch, 9 in. diameter, for straining the first varnish. A brass sieve, 40 meshes to the inch, 9 in. diameter, for straining gold size, turpentine, varnish, boiled oil, etc. A brass sieve, 40 meshes to the inch, and 9 in. diameter, for straining japan and Brunswick black.
A saddle, Fig. 6, which is a sheet of plate-iron or tin, 12 in. broad, and turned up 1 1/4 in. at each side; it is to lie from the edge of No. 1 pot on the edge of the funnel, to prevent the spilling of the varnish during the time of taking it out. A tin peuring pot, to hold 3 gallons, made exactly like a garden watering pot, only smaller at the spoilt, and without any rose; this is never to be used for any purpose except pouring oil of turpentine into the varnish. A 3-gallon tin jack, made with a strong handle at back, and a large broad spout in front; used for receiving the washings when poured out from the gum pot. A small broom, termed a swish, made from the waste cuttings of cane tied on a small handle, like a hearth broom, for washing out the gum pot each time it is used; to be always kept clean, and left in oil of turpentine. An iron trevet, made with a circular top 14 in. diameter, with four small cross-bars; the three feet of the trevet 12 in. high; it is used for setting the gum pot upon, with its bottom upwards, for a minute between each running.