Abstract: An external hydrostatic tester for testing welds on a pipe includes a tester body having a first portion and a second portion, each of the first and second portions having a first side, a second side, and an inner surface. The first and second portions are movable between a released position and a connected position. A testing cavity on the inner surface of first portion and second portion has a port for supplying pressurized fluid and is connected to a pressure sensor. Seals positioned on the inner surface of the tester body seal against a pipe and an adjustable compression member compresses the seals against the pipe at selected locations.