A gasket welding apparatus for heat fusible gasket members, the apparatus comprising: a first clamping member for supporting a first length of gasket material, the first clamping members comprising a first pair of jaws (18A, 18B) being moveable towards and away from one another; a second clamping member for supporting a second length of gasket material, the second clamping member comprising a second pair of jaws (18C, 18D) being moveable towards and away from one another; the first and second clamping members being movable with respect to each other; a first actuator (58P, 58C) for moving the first and second clamping members towards and away from one another; a heating element, the heating element being moveable between a first position in which it is removed from the clamping members and a second position in which it is disposed between the clamping members; a second actuator (62P, 68C) for moving the heating element between the first position and the second position; and a control unit for controlling operation of the first and second actuators, characterised in that at least one of the jaws of the first pair of jaws is reciprocally moveable along a first path having a first end defined by a first end stop, said at least one jaw being biased towards the first end stop, and wherein the first path comprises a second end defined by a second end stop, the first pair of jaws being coupled to a first overcentre mechanism, the said at least one jaw being biased towards the first or second end stop in dependence upon the state of the first overcentre mechanism; the first overcentre mechanism comprising a first handle manually operable to open and close the first pair of jaws and wherein at least one of the jaws of the second pair of jaws is reciprocally moveable along a second path having a first end defined by a first end stop, said at least one jaw being biased towards the first end stop, wherein the second path comprises a second end defined by a second end stop, the second pair of jaws being coupled to a second overcentre mechanism, the said at least one jaw being biased towards the first or second end stop in dependence upon the state of the second overcentre mechanism, the second overcentre mechanism comprising a second handle manually operable to open and close the second pair of jaws. a first clamping member for supporting a first length of gasket material, the first clamping members comprising a first pair of jaws (18A, 18B) being moveable towards and away from one another; a second clamping member for supporting a second length of gasket material, the second clamping member comprising a second pair of jaws (18C, 18D) being moveable towards and away from one another; the first and second clamping members being movable with respect to each other; a first actuator (58P, 58C) for moving the first and second clamping members towards and away from one another; a heating element, the heating element being moveable between a first position in which it is removed from the clamping members and a second position in which it is disposed between the clamping members; a second actuator (62P, 68C) for moving the heating element between the first position and the second position; and a control unit for controlling operation of the first and second actuators, characterised in that at least one of the jaws of the first pair of jaws is reciprocally moveable along a first path having a first end defined by a first end stop, said at least one jaw being biased towards the first end stop, and wherein the first path comprises a second end defined by a second end stop, the first pair of jaws being coupled to a first overcentre mechanism, the said at least one jaw being biased towards the first or second end stop in dependence upon the state of the first overcentre mechanism; the first overcentre mechanism comprising a first handle manually operable to open and close the first pair of jaws and wherein at least one of the jaws of the second pair of jaws is reciprocally moveable along a second path having a first end defined by a first end stop, said at least one jaw being biased towards the first end stop, wherein the second path comprises a second end defined by a second end stop, the second pair of jaws being coupled to a second overcentre mechanism, the said at least one jaw being biased towards the first or second end stop in dependence upon the state of the second overcentre mechanism, the second overcentre mechanism comprising a second handle manually operable to open and close the second pair of jaws.