[Bill4373]

A friend of mine was having some furnace work done. An extra piece was a hot air duct, 3 feet long and 8" in diameter. This is much better than using a tin can. It's already curved. Now to build a car that is 36" long!!! Used pieces can be obtained from heating companies and in different diameters.

 

[Ray Dunakin]

Is this a corrugated material, or plain?

 

[NavyTech]

I was thinking of using house duct piping and flattening it out to use for a metal roof. I wonder if that would work nice?

 

[Mik]

Just a guess, based on the info given... probably smooth galvanized steel, and about 18 gauge. If you're going through that kind of trouble. Aluminum flashing is thinner, easier to cut, comes in 20 foot rolls of various widths, fairly inexpensive, forms easier (also dents easier), etc

 

[Les]

I've found that stuff to be hard to flatten and generally difficult to work with because its a type of harder steel than you'd think. Flat sheets of the stuff can be gotten, or like Mik said, don't overlook aluminum flashing, though it does bend a tad too easily, sometimes.