Persons who use welding for making their own car repairs and fabricating parts, or as part of their production or repair business, will usually take classes to learn how to weld properly. Welding equipment is also very dangerous when used incorrectly and the right training will ensure a welder's safety. However, this doesn't mean that a welder will automatically know everything there is to know about welding and will never make mistakes, especially when just starting out. An instructor or class can't possibly envision every scenario where you might use welding for fabrication, so note a few common beginner's mistakes when it comes to welding so you can avoid these yourself.
1. Using low-hydrogen rods that have been exposed to moisture
Welding often involves using rods that are welded to two pieces of metal. Low-hydrogen rods are very popular to use for welding but because of their low hydrogen count, they are very susceptible to moisture. If these rods should get wet or moist in any way before or during the weld process, they will often bubble. It's good to keep them in a sealed container before use and if they have been exposed to moisture of any sort, heat them before using them to drain or dry away that moisture.
2. Trying to weld worn out metals
Metal is tough and durable but it can only take so much fabrication and corrosion before its overall composition is changed so severely that it cannot be welded without being cut right through, or before it becomes weak. If you note that a metal piece has been welded before or has been pounded, bent, cut, rusted, or otherwise is very worn, you may need to reinforce the metal before you weld it. This might involve riveting a second sheet underneath it or ensuring you use rods during the weld rather than trying to simply weld two pieces together. Otherwise, the worn metal will create a very weak welding point and may not hold up during the welding process itself.
3. Not welding fast enough
When welding, you need to ensure you use the right technique for your metal but many beginners fail to weld fast enough, as the rod or metal pieces need to soften to be welded together. Allowing them to get too soft and not using the right speed for your pass will mean a pool of weld metal that deposits onto the piece, and a poor quality weld overall.