Corner for bed frame, using 1/2 x1/2 square aluminum "C" material

Been making an aluminum bed to attach heated pcb board to. Using extruded "c" shaped aluminum rail I made these corners to attach metal together. If made in abs, the acetone bath should melt off just enough to make everything slide together nice as well as mounts for nut and bolts...If made in pla, a little sanding and pressure fitting to get nuts to fit in their designated slots. .