Vacuum box testing is an effective leak testing technique used to inspect welding joints. This is a relatively fast and one that can be conducted without interfering with other fabrication operations. That test uses a box fitted with rubber seals around its open bottom and a plexiglass top cover. The weld section to be inspected is coated with a soap–like solution and a light vacuum. The formation of bubbles on the soaped weld indicates the location of a leak.
