Because clay-based adhesives don't have the same viscosity as clears, you need more gears. In a multiple-roller machine, a bottom roller will agitate the clay and keep it runny. In addition, clays perform best if a machine's paste tray is sloped or V-shaped, rather than a basic rectangular pan, said Lorist. The slope will keep the adhesive flowing into the machine and prevent it from settling. The paste tray is a permanent feature on a machine and cannot be changed, of course, so you'd better know what you're looking for going in.
Some contractors experience skips in coverage when using clays in pasting machines.
While a sloped pan should help prevent this, you should also keep the tray filled higher with clay than you would with clears, Keelan suggested. If you intend to use a machine with a prepasted wallcovering, you must use an activator, which can be poured right into the machine. We introduced an activator just for that reason. The activator has just enough viscosity to be picked up by the rollers. You should never thin an activator.