TIPS FOR FIELD WELDING - First up - Prepare weld joint. This involves cutting out old welds and material with a carbon arc gouger, torch, plasma cutter, or grinder. Be sure there are no cracks or crystallized material left over as this will weaken the weld. Then clean the weld joints with a wire brush or grinding wheel
so they are free of paint, oil, dirt, or other contaminants. This will make for a nice clean porosity-free weld.
Always carry two grinders with you, preferably cordless. One with a wire wheel and one with a grinding wheel. This will save you a ton of time and headache not having to change them out all the time.
Next - Bevel the edges 30* where necessary. This allows for better penetration of the weld.
Next - Choose the proper filling material for the joint. If it is a heavy piece of equipment that is out there taking a pounding all day you would want to go with a 7018 filler rod when using (SMAW). If it's an old piece of cast aluminum you would go with a 4043 filler rod when using AC (TIG) or AC (MIG). Think in terms of Tensile Strength, Ductility, Malleability, and Wear Resistance. Just remember the filler material you choose needs to meet or exceed the strength of the parent metal that you are welding together.
Finally - Select the proper current type and heat range. DC for Steel and AC for aluminum because of its cleaning action of the current alternating back and forth. If using the MIG process you will also be dealing with wire speed. Always set up your welder using a practice piece of material of the same thickness. When adjusting your amperage you want a nice even flow of the weld puddle, no balling up because of not enough heat, or undercutting because of too much heat. When adjusting your wire speed you will be listening for a nice clean crackling sound with very few sputters or dead space. Make notes of your settings for next time.
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