Polystyrene or similar blocks shaped at joint faces - by steam heat and pressure, to compact material adjacent to joint and render it stronger

摘要

A method of deforming plastic blocks or the like for the purpose of making joints, typically sawtooth, dovetail or similar joints, consists of heating the block with steam under pressure and thus deforming its surface to the required shape. In a typical arrangement a block or panel of polystyrene is enclosed by a hollow steam-heated mould, and a tapered tool is pushed into its end as it softens. Both the mould and the tool have perforations for the passage of steam. The method is used for forming mating joints in blocks and has the advantage that the material is condensed, compacted and rendered stronger around the joints, exactly the opposite from the result achieved when edges are sawn or cut.