First, you must buy a reliable machine. There are a variety of welding machines performing various functions. By knowing your task, you will be able to choose a suitable welding machine.
It’s all about how clean the material you are about to weld. It all start with the good fit. Materials are cleaned thoroughly and bevelled perfectly as you can. Using tack welding, hold your material together safely to get the perfect end-product. In open root welding, tacked backing plate is not used. Welding is done across the gap, which is quite tricky. Always break your pipe on the sidewall. Afterwards, start from the arc from the weld pool, then gradually transverse from corner to corner on the other side and crisscross the surface.
Before start, you must develop safety techniques which include safety goggles, work boots, apron, helmet, fire-resistant costume, and earmuffs. Furthermore, the welder's hand side will decide the side of work. Some welding positions are discussed below:
1G ROLLED: Start the arc from the center of the tack so that your gun is perpendicular to the pipe with a drag angle ranging from 5 to 10 degrees. Stick out should be a maximum of 5/8 inches. It is the most used position.
The weld position must be in the middle of the puddle as the pipe rolls away from you. Drag the welder. There is no need to weave for this position lest your gap is larger than 3/16 inches and requires a sidewalk bridge.
2G ROLLED: In this position, pipe and weld positions cannot be rotated at the same time. The pipe can rotate on the vertical (Y) axis while welding is done horizontally.
5G FIXED: It is the same as the 1G position, unlike the welder cannot rotate pipe. You will move the electrode back and forth across the gap with a half-moon position while the moon faces down.
Stop weaving when gravity begins to show its presence. Use a little side-to-side position at the base. To avoid pinhole on the finish, end the bead on feathered tack weld.
On completing the root pass, you need to grind out your starts and stops before making fill passes.
6G POSITION: 6G welding position involves fixing your pipe at 45 degree in a horizontal or vertical position. So, welding is accomplished by using both weak and robust welder sides. It requires high experience.
More tips: Molten material disperses droplets around the arc, and this is called Spatter. In this situation, lessen the currents and use proper polarity. You can also reduce arc length and increase the working angle.
Porosity arises when gases get absorbed in the weld pool when the welding surface is not cleaned and ground correctly. Try rebaking, using new welding consumables, and checking leaks with a torch to encounter this problem.
Long and high voltage arc results in undercutting. Also, when the angle is not correct and the electrode is not appropriate for the plate thickness. So, weld at a steady pace.
Cracks are a significant defect as they cannot be filled with any material. This requires new welding. To avoid the situation, Clean and grind the surface properly before welding and use the required heat level.