NO, that is absolutely dangerous. No matter you wear contacts or not, welding is a dangerous activity. Workers are always equipped well enough to protect themselves, especially their eyes. The temperature on the spot is very high, if the contacts are near it, the material of resin could be very fragile and give out some harmful substances, which are bad for the eyes. Moreover, the harmful gases and dust around the spot can be easily attached to the surface of contacts, which will also lead to denaturation of serin. So be certain not to wear contacts while welding and protect yourself well.