Cheapest way to make a new waveguide monopole

The waveguide in the centre of antennae sich as cantennae are made of a copper quarter wave monopole. The cheapest way to obtain a stiff enough short piece of copper wire is to scrounge a spare piece of 3 core 15A ring-main household wiring (the stiff grey stuff) and strip out the wires and remove the blue and brown coloured plastic coating from the individual wires).