flooring underlayment for use in an IX style UQ

[sunny]

So I was meandering through Big Lots today looking at their stuff. I just happened to noticed a couple of rolls of flooring underlayment. It was super light weight (I don't think the whole roll weighed more than a pound and a half) and appeared to a be a 1/8" CCF type material. For the price ($20) there is more than enough material to make two 4 layer underquilts. Has anyone tried to use underlayment for insulation in an underquilt? The price and weight of this makes it incredibly tempting. Any thoughts or suggestions would be greatly appreciated.

[heyyou]

One of the early IX users has switched from using IX with its extra layer, to using just the foam without the extra layer. Expect others to come along soon and add the details to this vague response.

[Klaussinator]

What you're looking at is at least twice as thick as the furniture wrap that I used. I've had great results with my 4-layer IX UQ, so I think the underlayment should work fine.

-Klauss

[Lost_Biker]

I use the underlayment from Home Depot thats 3/32 thick. Works quite well - the only drawback is that the thickness means that you can't really fold it up to a compact size. It is very light weigh though and the 4 that I've made for people are still being used for temps above freezing. There's too much condensation build up below freezing temps.