I made my own by glueing alternate lengths (about 2 inches) of .10 x .30 and .10 x .40 styrene on edge onto a piece of .40 thick styrene sheet (as a base) to create a form for the corregated steel. This part is about 4 scale feet wide. I cut off about a 1/8 inch long piece of the laminated strips, which I attached a suitably thick piece of styrene as a handle, to create a ‘rake’ to press strips of 4 foot wide strips of aluminum foil into the corregated sheets. I had to gently file the edges of the ‘rake’ to make sure it didn’t snag the foil sheet, but otherwise it works pretty well.