I had some leftover charcoal and a cheap BBQ grill. I mounded up the charcoal over the top of several small armatures, lit it and closed the top of the BBQ. Well, a little vent on top of the BBQ was left open. Went back after it had cooled down and found the varnish had burned off. It was easy to pull the copper wire out. So would reccomend a low heat rather than trying to meld the copper, Mike.