Isinglass is made from fish swim bladders; it's kinda similar to glue when reconstituted, and I've only ever used it in beer and winemaking, for clarifying. The windows are mica - I've got some steel and brass Stonebridges, I like them and still use them. You can find mica sheets at places that carry supplies for wood stoves - might try www.lehmans.com or www.cumberlandgeneral.com. I also had one of the cylindrical French alpine aluminum candle lanterns for backpacking back in the 70's; they were too flimsy to last, but useful.