MODELS 427A, 428A, 429A The R-Head series of weld Heads are easy-to-operate tools for welding pipe. Three standard models cover pipe sizes 12.7mm to 168mm OD (0.5" - 6.625"). A mechanical arc length control device compensates for out-of-round pipe. The basic weld Heads can be used for fusion welding applications. Filler wire feed modules are standard for all models. The weld Head is simply slipped over the pipe and clamped with a toggle lever. The Second Generation design provides continuously adjustable clamping - no need to interchange components when changing pipe sizes. Redheads clamp only on one side of the weld joint, allowing use for pipe-to-fitting welds. Used with the Tubemaster power source, these weld Heads improve productivity by increasing duty cycle, reducing repair rates and producing welds of consistent quality.