So in my experimentation lately making gear, I've made a nice little Underquilt out of an old kids coleman sleeping bag that has been good to me down to about 45 so far, it will easily go colder I think. But not one to leave well enough alone I decided I wanted to play with a Poncho Liner I had in the camp gear.
I took the poncho liner and cut it in half and squared it up. Then took 2 of the Jumbo Sunshades from Walmart ($3ea), squared them up by cutting off the section with a "V" for the mirror, and sewed the two together down the center with a strip of grosgrain. Put that between the 2 layers of poncho liner and sewed it all together with some grosgrain as channels on all 4 sides. A little bit of Shock cord on the short ends with cord locks and run some 550 through the long channels to suspend it with some loops of bungee at the ends.
I wasn't sure at first if it would be too stiff, but I've spent 2 nights in it so far and its been great. The temps have only gotten down to the low 50's here at the house, but its been toasty at those temps so far.
I sewed in the reflective sunshade with the reflective side UP, and there is a noticeable difference when reversing the quilt so its facing out. Maybe good for warmer weather without overheating? You can definately feel the heat radiating back at you when its facing up.
This morning was a nice test, woke up and noticed it was cold and windy outside. Temps were in the low 50s, and wind was gusting up to 25mph and chilly. I threw the hammock on the stand and jumped in. I've been testing with shirt off, and just thin shorts, no socks as that is how I like to sleep normally. I had my 40deg Eureka bag as my Top Quilt, my little Diy down pillow and thats it. The wind was coming straight down the hammock from head to foot. I had to get every nook and cranny covered on top to keep the wind out, but once I was in I was very toasty. I noticed every so often a little cold spot at my shoulders but was able to reach out and tighten the end of the quilt a little and that closed up the gap. This was about 5am, and I woke up about 7am due to the sun, still howling wind and cold outside, but didn't even notice it as I was all toasty in the hammock. I also was careful not to let the top quilt get under me, as I wanted to know what only the UQ and hammock were doing without the TQ adding to the bottom insulation at all.
So the total cost of this little experiment was just the grosgrain and sunshades, so about $10.... It works great so far, and I'll keep testing it lower as it gets colder. It might be good to low 40's for me or colder, I'm a warm sleeper. With the foam sunshade it doesn't compress as small as just the poncho liner does, but it gets pretty small. Little smaller than a coffee can. fold in half and half again, then roll.
But I've already got a 2nd revision in mind...
This time 2 poncho liners to get a bit more width and length out of it, and cutting the ouside shell wider than the inside to create a little more air gap between it all so its not as compressed under me. Also take the extra width and length to create draft tubes all around to help it seal up to the hammock nice and easy.
Couple phone pics...