The brass C profile is a channel with the lip of each flange turned inwards, which is the shape real construction uses for thin-walled framing and track. On a model it becomes rails, guide channels for sliding parts, edge trims on body sides and light structural work where the wall has to be thinner than a styrene section would allow. Brass also takes solder, so a C-channel joint survives genuine mechanical load rather than simply holding together. A soldered channel frame is built in the order that keeps the earlier joints from letting go: tack the corners first, then run each seam with the smallest iron that will heat the section through. Angles, flat bar and hollow box in the same metal are in brass profiles and sections, and round stock in brass tube.
