Thermoforming pressure box adjustable in two dimensions and method of use

A method of adjusting length and width dimensions of a thermoforming pressure box, said thermoforming pressure box having a horizontal top plate, first and second vertical end plates extending orthogonally downwardly from a lower surface of said top plate, first and second vertical side plates extending orthogonally downwardly from said lower surface of said top plate, said first and second end plates and said first and second side plates mating such that said top plate, said first and second end plates, and said first and second side plates form a downwardly open rectangular parallelopipidon having first length and width dimensions, said method comprising;

• (a) repositioning said second vertical end plate on said lower surface of said top plate in a direction parallel to an index direction;
• (b) repositioning at least one of said first and second side plates on said lower surface of top plate in a direction orthogonal to said index direction;
• and
• (c) replacing said first and second end plates with third and fourth end plates mating with said first and second side plates so as to form a downwardly open rectangular parallelopipidon with second length and width dimensions
• whereby, said pressure box is provided with a plurality of fasteners attaching said side plates to said top plate, said fasteners extending from said side plates into said top plate, and said fasteners being disposed in windows defined in said side plates.