Sheet metal is too heavy. I keep my gutter-flashing foil windscreen, with paper clip adjustment, lightly rolled in my Titan Kettle. Gutter flashing is a little heavier than aluminum foil. It can take abuse .

And now for the soap box.
Please don’t get discouraged with titanium alcohol stoves. A lot of people get turned off of alcy stoves because their first stove was a vargo titanium alcy stove. There is a big fiddle factor w/ these stoves. When it gets a little cool outside, you will also need a 2nd stove to start the Ti stove. Certain styles of aluminum soda can stoves perform about 10x better because of better heat conduction and ease of lighting.

-Barry