I used both Wonder Under and Foil-on Textile Transfer Adhesive in my foiling tests. Patty foiled many peace symbols on a yellow hand dyed fabric. Foiling takes a lot of muscle! I'm not sure you'll see any of it in my work, as I'm not a glitz girl.
We also played with painted Tyvek fabric. I think Patty's piece would be great as the focal point in a larger project. I can envision it embellished with beads and fibers. Note: Tyvek fabric is far superior to Tyvek envelopes. Besides, new U.S. Postal materials are for mailing purposes only. It's OK to use canceled envelopes.
I purchased Tyvek fabric from New Zealand fiber artist Stephanie Quattrini at our guild show. http://www.hanzoncreativity.com/
Artificial ferns from the dollar store were pinned to still wet fabric which had been painted with Pebeo Setacolor Transparent paint. This paint is heliographic, meaning it is light sensitive. When set in the bright sun, it reacted beautifully, leaving a crisp fern print.
Note: Make sure items used for sunprinting touch the painted fabric firmly. Loose items allow too much shadow and do not make a crisp print. Remember to do sunprinting while the fabric is still wet. On cloudy days, an Ott light is a good substitute for the sun. I've even used regular lamps.
Patty pinned the end of each frond fern to ensure a crisp print. The fabric was painted on a piece of old foam core, making this an easy task.