A person who is looking at having a career in the ship building and repair, automotive manufacture and repair, industrial equipment production and construction industries will need to learn how to weld first before they can have a chance to get hired because it is rare for companies and government agencies to hire workers first and then train them afterwards. Of course, it would make sense for companies to invest in employees who have already taken the initiative to learn how to weld instead of spending money and company hours on an employee who still needs to learn how to weld. This is true even if the employee with no practical experience has read all the welding books in the world and have been exposed to an environment where welding is commonplace.
There is undeniably good money to be made in welding jobs because this is skilled work that earns competitively, even more than some white-collar positions in some companies. However, not all aspiring welders have the money to enroll in a welding class or the time to spend in taking formal welding lessons. So what is a viable option? Is it possible for a person to learn how to weld without enrolling in a formal class?
If your only goal is to make sure that a few pieces of metal stick together, you are not strict about how neat the weld looks like, and no life or property is at risk of injury or devastation from your work, then you can practice welding on your own.
Take note that it may sometimes look easy especially if a professional welder is already doing it, but welding is a difficult skill to learn. It takes a lot of patience, time, and many poorly welded metal pieces that would go straight to a junk or scrap yard before you can produce work that is actually worth being paid for.