Vacuum
Priming method especially suitable for casings, consisting of the following steps:
1) Negative pressure in autoclave to remove most of the air from the wood intercellular gaps.
2) Inlet of the priming product in the autoclave, which gradually reaches the atmospheric pressure, thereby helping the primer penetration, due to the difference of pressure produced by the previous vacuum treatment. The intercellular gap vacuum helps a deep penetration.
3) Emptying of the autoclave and final vacuum, which is higher than the first stage and therefore helps the exit of excess primer.
4) The item is returned to atmospheric pressure, which causes a return of the primer still on the surface, with consequent drying of the same.