OK heres the deal. I am testing a new type of air mattress from Big Agnes on my hike. So far it has been great on the many nights that I was unable to hang. Unfortunately it is getting too cool for an uninsulated airmat. The valve is made of aluminum and I accidentally unscrewed the top completely off the mat. I thought HMMM, I wonder if I could insert some down into the the valve and make a lightweight DAM. Actually I first thought that I had ruined the mat, it was after I was able to get the cap back on the valve I thought of the down. Anyway, the opening is only about 3/8" in diameter. I know some of you are experienced in working with down and I was wondering if I could use comperssed air (of mabe even my breath) to inject some down into the mat. If I can get this to work I can have a DAM for about a pound. Any thoughts, anyone, anyone, Bueller?