Forming a channel letter box using a profile, including: determining an incision position on one surface of the profile where at least one surface incision is to be made; surface incising at the determined position; folding the profile at the incision position to form the channel letter box, wherein the profile comprises at least one protruding rib on one surface of the profile; and cutting and attaching a top plate to the channel letter box, wherein a thickness of the top plate is substantially close to a distance from the top of the profile to the top of a top rib of the at least one rib.