 Similarly, a plug that was hot enough to run smoothly in town could melt when called upon to cope with extended high speed running on motorways.The answer to this problem, devised by the spark plug manufacturers, was to use a different material and design for the centre electrode that would be able to carry the heat of combustion away from the tip more effectively than a solid nickel alloy could.Copper was the material chosen for the task and a method for manufacturing the copper-cored centre electrode was created by Floform.