I plan on making them tommorow out of aluminum. Will aluminum work good for this or do i need copper or brass? Also should I solder it on all the way around the heatercore or just in the corners? Also should the folds be soldered together? I was thinking about having 1.5" space between the fan and core, this enough, to much or to little? I also have some rivets that i could use to hold the folds together do you think this would work better than solder?