Never mind slots. Aneal the ally with oxy acet heater torch, slowly working along the length (do it in one 4m length and get a much stronger edge). Get it to near melt point but not too close. Let it cool to handling temp, then fix one end on the craft and work round, bending and fixing as you go. You've got about 20mins before it re-hardens (ie. it remains soft enough to bend/mallet even when cold).

Tony S.