Brad, this is an incredible build . Beautiful. I might have a source for aluminum . I have used it in the past and still do. Flashing material for eaves and covering windows. A few bigbox stores have it ( Home Depot, Lowes ). I have found it plain and it comes in a roll. Enough for a lifetime.Another source is disposable foil cooking pans .Look for large pans without any embossing on the bottom.The material is thin but it works. Hope this helps a few people.