Don't watch welding without adequate dark glass filters. You can get a tan in 2 minutes and a burn in five on any exposed skin close to arc welding. It doesn't hurt for about 3 hours, but then it hurts for days. Don't play with air. Sometimes right through the skin.
Air is no joke.
In general, no horseplay in the shop. Banish anybody who can't understand this simple rule. This is one place where absolute dictatorship is better than democracy. Take your time. You'll save on rework time, machine repair, and medical costs.