If you are only interested in acquiring an entry level position as a welder, you generally need to only complete a few weeks of schooling.  In some cases, you can acquire an entry level position without much formal training, in which case you will receive on-the-job training instead.  If you want to earn a higher wage and take on those jobs that require a higher skill level, however, you will need to complete several years of training and schooling. 

Some employers offer training to welders, but most prefer those that have already been trained in the trade.  This training in available through private welding schools, vocational-technical institutes, and community colleges.  Regardless of where you receive your training, you will take coursework in subjects such as shop mathematics, blueprint reading, physics, mechanical drawing, chemistry, and more.