CRC-Evans can provide customers with a range of automatic welding support equipment. This equipment is available for projects anywhere in the world. A device that is placed around the circumference of the pipe that an External Welder Machine is designed to clamp onto and drive around. They are usually manufactured from 5" wide spring steel rolled to a diameter 1" greater than the OD of the pipe and then spaced about 5/8" off the OD of the pipe. Tractor designed to supply compressed air and electrical power to and Internal Welding Machine. The tractor will also carry a supply of shielding gas to refill the gas bottles located on the Internal Welder. The power supplies used by the External Welding Machine are also mounted on the tack rig. Tractor or side boom designed to supply electrical power and shielding gas to External Welding Machines. The tractor will also carry a "shack" or "tent" to provide shelter for the External Welding Machines. The back end rig also carries the power supplies used by the External Welding Machines. A relatively small enclosure approximately 12' wide and 10' long and about 8' high that External Welding machine are mounted in that are carried from one joint to the next by a back end rig. The shack typically is a light weight metal frame covered with thin sheet metal. A shack will have a special floor designed to pivot up to allow the shack to be lowered onto the pipe and then pivot back down to allow easy access to the pipe. Shacks provide the welder lighting and protection from the elements. Basically a tent is a economical version of a shack. Typically a tent is the same size as a shack but it does not have the floor and is usually cover in a heavy canvas. Tents are also lighter than shacks of the same size making it possible to use smaller tractors for the back end rigs. Tents also provide the welders lighting and protection from the elements.