Yep, don't breathe in, hold your breath.
From the Brasslite stove website do-it-yourself page: 0.5 inch stainless steel wire cloth. Can also be gotten from McMaster-Carr. Search for "wire mesh", choose Type 304 stainless steel welded wire cloth 2x2 mesh per linear inch. It comes in 36in. width, but you have to buy a 3 sq. ft. minimum. It's possible to use 1/2in. galvanized wire cloth from a hardware store, but it has poor durability and is more difficult to solder. One square foot is enough to make 12 stoves.