Does anyone work in construction as a means to an end?

Does anyone work in construction to fund a side gig they wish to turn into their main source of income? I am considering becoming a laborer so that I can work temporary jobs while working on my side gig during the off time. Now I don’t know if the union asks “why do you want to be an apprentice” but I’m wondering if it’s looked down upon to not want this to be my permanent career.