Robert, If you prestretch that wire it will no longer stretch. I have always prestretched any wire I have used in modeling or otherwise. A machinest friend had a more technical solution, but simply heat and stretch, no more problem, most wire has been cold rolled and pulled through a die to get its diameter, once you heat and stretch the wire it will no longer want to stretch on your model,wire only has so much give befor it completely fails.I have gotten 4 - 6 in of stretch on a 10 ft. length of same diameter of wire you sent out. It will make diameter of wire a little thinner. Also be very careful when placing this wire under tension,can snap very easily. George