Are mandrel bends stronger for doing say roll cages and frame re- inforcements? Need to make a cage and re-inforce my frame, if mandrel bends are stronger would it be wise to buy a bench of bends in the right diameter then weld them to the straight pieces? I'm thinlking of buying one of those China hydraulic benders from Harbor Freight, Anyone ever use one? Are they worth it? Thanks, Slappy.