A material welder for welding portions of a material together, including: a top bar assembly and a bottom bar assembly, each assembly extending in a longitudinal direction, a portion of the top bar assembly being directly above a portion of the bottom bar assembly, the top bar assembly including a first and second heating element (21a, 21c) substantially in the same plane and the bottom bar assembly including a first and second heating element (21b, 21d) substantially in the same plane; at least one heating device adapted to selectively heat the first heating elements (21a, 21c) and/or the second heating elements (21b, 21d); an actuator device adapted to move the top bar assembly towards the bottom bar assembly and/or the bottom bar assembly towards the top bar assembly such that the first heating element of the top bar assembly aligns with the first heating element of the bottom bar assembly and the second heating element of the top bar assembly aligns with the second heating element of the bottom bar assembly; and contact surfaces (11a-11d) associated with respective heating elements (21a-21d) of each of the bar assemblies adapted to contact the material during a welding process, the contact surfaces (11a-11d) comprising: top contact surfaces (11a, 11c) of the top bar assembly and; bottom contact surfaces (11b, 11d) of the bottom bar assembly, characterised in the top contact surfaces (11a, 11c) being adjacent one another in a transverse direction and the bottom contact surfaces (11b, 11d) being adjacent one another in the transverse direction such that when the top and bottom contact surfaces (11a-11d) contact the material and all the heating elements (21a-21d) are heated, the resulting weld is continuous in the transverse direction. a top bar assembly and a bottom bar assembly, each assembly extending in a longitudinal direction, a portion of the top bar assembly being directly above a portion of the bottom bar assembly, the top bar assembly including a first and second heating element (21a, 21c) substantially in the same plane and the bottom bar assembly including a first and second heating element (21b, 21d) substantially in the same plane; at least one heating device adapted to selectively heat the first heating elements (21a, 21c) and/or the second heating elements (21b, 21d); an actuator device adapted to move the top bar assembly towards the bottom bar assembly and/or the bottom bar assembly towards the top bar assembly such that the first heating element of the top bar assembly aligns with the first heating element of the bottom bar assembly and the second heating element of the top bar assembly aligns with the second heating element of the bottom bar assembly; and contact surfaces (11a-11d) associated with respective heating elements (21a-21d) of each of the bar assemblies adapted to contact the material during a welding process, the contact surfaces (11a-11d) comprising: top contact surfaces (11a, 11c) of the top bar assembly and; bottom contact surfaces (11b, 11d) of the bottom bar assembly, characterised in the top contact surfaces (11a, 11c) being adjacent one another in a transverse direction and the bottom contact surfaces (11b, 11d) being adjacent one another in the transverse direction such that when the top and bottom contact surfaces (11a-11d) contact the material and all the heating elements (21a-21d) are heated, the resulting weld is continuous in the transverse direction. top contact surfaces (11a, 11c) of the top bar assembly and; bottom contact surfaces (11b, 11d) of the bottom bar assembly, characterised in the top contact surfaces (11a, 11c) being adjacent one another in a transverse direction and the bottom contact surfaces (11b, 11d) being adjacent one another in the transverse direction such that when the top and bottom contact surfaces (11a-11d) contact the material and all the heating elements (21a-21d) are heated, the resulting weld is continuous in the transverse direction.