Alignment of Parts

When accurate re‑alignment of a broken section is required do not completely eliminate the fractured mating surfaces with your preparation. Leave a section for re‑location of the two parts in the correct alignment to each other. If necessary, this section can be ground out from the alternate side once a strong weld has been made in one side of the prepared section.

Take solid round sections to a chisel edge preparation ‑ not a point.

Welding of Pipe Sections

Pipe and tubing are popular for a wide range of structural fabrication requirements such as roof trusses, gates, partitions, sheep pens, trailers, being the structural form providing the greatest strength for its cross sectional area. Because of its curved surface and fact that it can be welded from the outside only it does pose a slightly greater problem in preparation and welding.

In butt welds turn the pipe where practicable for easier welding.

Where this cannot be done and welding must be carried out in all positions remember that to maintain correct electrode angle, the hand must move much faster than the electrode tip. Usually down technique will be found easier in the smaller thin walled pipes and tubes.

If galvanised, clean as much coating from the actual weld zone as possible to reduce fuming and ensure adequate ventilation.

A section of round or smaller tube fitting inside the pipe to be joined can provide a backing ring for easier welding in important butt joints. In mitre joints, weld from the outer point towards the heel. In making a tee joint capable of carrying water ‑ a branch and header pipe ‑ the hole must of course be cut in the header before the branch is welded into place.

First cut the branch square and sitting it on the header pipE measure distance D between the branch end and the header wa as illustrated in Fig. 35. Scribe freehand the profile around th branch pipe, B being equal to D. Cut and grind the branch to fit ovc header neatly, mark the cut and then allowing for pipe wa thickness, mark and cut an inner section.