Vacuum Pressure Impregnation (VPI)
When using VPI equipment the clean and dry object could be dried with vacuum even before the impregnating process starts.
Impregnation takes place under a vacuum of 50 - 0,01 mbar at differing times and temperatures depending on the resin / varnish and object type. After the vacuum cycles the impregnation process is continued with an over pressure in the range of 1 - 6 bar. The total process cycle will be dependant upon the object type and resin system utilised.
Objects impregnated with varnishes or resins are drained for a specific time at room temperature prior to the product being cured in an oven. Times and temperatures will vary depending on the object type and size as well as the time given. Depending on the resin / varnish system a two-stage curing process could be recommended. To better anticipate the time and energy consumption necessary for the objects to be impregnated, heating curves and curing temperatures should be considered.