I use steam both in my indoor oven, and outdoors in a Komodo Kamado ceramic barbecue cooker. I got tired of cleaning yard schmutz out of my stainless steel chains, so I ordered a second aluminum disk off eBay. My steam generator now consists of one cake pan and two disks, all aluminum:
Fat Daddio's PRD-163 Round Cake Pan, 16 x 3 Inch (Amazon)
1 Aluminum Disc, 1 1/4" thick x 14 3/4" dia., Mic-6 Cast Tooling Plate, Disk (eBay)
To my surprise when I redid my calculations, aluminum has a significantly higher specific heat capacity than steel: Water, 4181. Aluminum, 897. Ratio: 21.5% Moreover, these disks are heavy. The cake pan and two disks combine to 44.9 pounds. So, in a ceramic cooker or oven heated to 450 F, this steam source can boil off 803 grams of ice, or 964 grams of warm (40 C) water. I rarely use more than half that, enough steam to replace the air in a KK or oven several times over. Perhaps I should have just tossed the steel chain, but now I have two aluminum disks. Nice.
I posted this in a Komodo Kamado forum thread, where others have followed my lead, finding that one disk is plenty. (I'm best known there for devising a cast iron Dutch Oven "smoke pot" for a more subtle smoke flavor without the nasties. This got propagated to other BBQ sites.)
I was thrilled to get rid of the chains. They're messy and awkward.
