Progress, page 108
I needed a collar of some sort to go around the last chimney section at the rooftop, and it needed
to be strong enough to support the decorative concrete surround that I intend to finsih it with. It
also needed to be corrosion resistant. I still had some sheets of heavy (about 1/16 inch thick)
copper left that I had used to fabricate the roof scuppers, so I cut a hole in the center of one and
gradually hammered it out to make this toilet seat shape. It's 30 inches on a side and the hole
after hammering is just over 14 inches (the outside diameter of 12 inch insulated chimney). It
turned out so nice I may try to make some other hammered copper items later just for the heck
Here's the actual upper side of the copper collar as it will be when installed. I had to fasten the
copper sheet to a wooden frame before hammering it to prevent it from getting all deformed.
The top of the chimney box on the roof already had a good weatherproof membrane across it, so
I just cut a hole in it, passed the chimney section through it, and fastened the copper collar to the
chimney box with a good silicone caulk. I'll apply a high temperature caulk to the joint between
the collar and the chimney before I cast a concrete shape over the top of the box.