I’ve got a chipper truck with the steel sides and not enough room for painting our company info or vinyl. What kind of sign do I get and from where? Are most of the companies with dump trucks using metal signs or what?
Plywood. Self tapping screws every foot or so should be secure, small pilot holes.
Prime the plywood first. Two light coats is better than one heavy coat.
Could also do magnetic signs on the truck doors. Looks professional enough rolling up to the job, but nobody will get your phone number on the road probably.
Keep the lettering large. Too many side signs use a font that looks like a business card which can't be read from across the street. Don't clutter up the sign with lists of what services you provide.