1. Robert Brent SR-20 Slab Roller, table model, consists of a moveable roller/carriage mounted on a steel table and frame and a series of removable 1/8 inch and 1/4 inch think shims (masonite boards). The shims are either added to produce a thinner slab or are removed to produce a thicker slab. Extra shims are found on the plywood shelf underneath the slab roller. The top shim should always be one covered with canvas; a single dry sheet of newspaper (folded over once) is laid on top of and parallel to the length of the shim; thick slices of clay (no more than double the thickness of the intended slab) are laid on top of the newspaper, their edges overlapping and the seams worked together on both sides; a second single sheet of newspaper (folded over once) is laid on top of the clay; the heavy canvas is pulled over the paper; the roller/carriage is rolled down over the canvas and is returned; and then the canvas is pulled back over the top of the carriage so that it hangs down over the end of the slab roller frame. Never place a solid chunk, ball, or mass of clay on the canvas, without pre-slicing, as this will damage the roller. Remove the clay slab immediately and transfer it to clean dry newspaper or cloth. Care should be taken so as not to put any wrinkles in the heavy canvas. Be sure to clean off any clay residue on any part of the slab roller and shims. The maximum dimensions for clay slabs with this roller are 20 inches wide and 60 inches long. Thickness can range from 1/8 inch to 1 1/4 inch depending upon the number of shims used. For TILES cut from slabs, it is suggested that the slab be rolled one shim thicker on a first roll, then flipped over (end to end) on a fresh dry sheet of newspaper and rolled again to the desired thickness after a shim has been added. This procedure helps to prevent warping. Strips of canvas or other cloth are ideal for rolling out slabs instead of newspaper one under and one on top of the clay.
2. Randall XT wall mounted clay extruder, consists of a large 6 Ό inch inside barrel that is 15 ½ inches long; a plunger/hand lever; a removable die holder; and a steel tripod for hollow forms dies and a series of dies all of which should be clean before beginning. A die is selected and placed inside the die-holder. The die-holder is pulled up over the bottom of the barrel and twisted on to lock it in place. If a two-part die is used, as for extruding hollow forms, then the inner/center die that is screwed onto the steel tripod is centered from the top of the barrel until it is equidistant. A rounded plug of soft clay that has been well wedged is put into the barrel from the top and finally the round plate that is attached to the hand lever is placed on top of the clay and the back of the hand lever is latched into one of the notches in the angle iron ratchet and the hand lever is pulled down to force clay through the die. Two people may be required to pull down on the handle of the plunger and a third person should be available to catch extruded clay. The design of this extruder precludes the use of the top 3 inches of the clay plug to protect the steel triangle so you must compensate with enough clay to fulfill your needs. When you are finished, disassemble the parts of the extruder. After you have removed the die holder, it may be necessary to reach inside the barrel and push down on the remaining clay to remove it. Then scrub and sponge clean ALL PARTS of the extruder and apply a thin coat of Vaseline or WD-40 to the inside of the die-holder and also the bolt from the steel triangle before re-assembly. Be sure to put away any dies you have used.
You may also make your own dies for extruding solid forms, from thick porcelain slabs (fired to maturity) or from metal sheets cut to fit the die-holder. There are also two types of handheld extruders and a multitude of dies to fit these in the labeled drawer where the large dies for the Randall extruder are stored. When using either of these, be sure that your clay is very soft and does not contain coarse grog or sand. When you are finished, disassemble, clean the parts, and return to the storage drawer.