Having made my first underquilt recently with the insulation being regular 5 oz polyester batting and finding it a bit narrow and also not warm enough for my tastes, I decided to invest in some real insulation and bought up some Climashield Apex 6 oz and got to work.
I made a very simple 48 x 60 underquilt. I sandwiched the Apex between two layers of 1.1 ripstop and sewed the edges. Then I created my own binding material by taking strips of ripstop and sewing a hem to make them tubular. Then I placed the seam side against the edge of the quilt and sewed the channel and binding all in one over the edges. This being the quickest easiest method (for me).
I decided to go with the full 48 x 60 inches without sewing a hem because I wanted the full length of the fabric. Using the additional fabric binder added a few hours to the project but the results are less material being wasted and a bigger size quilt with more insulation being put to use rather than scrunched down due to hemming the edges like I've seen how other underquilts are done.
Last year I invested heavily in Big Agnes gear. So I need to keep using some of it and so I have the Mystic SL sleeping bag I highly recommend this bag to anyone who's not hammocking. It's the best **** bag in the world in my opinion. Warm warm warm and snuggly and comfy and it's not heavy. Of course it being a Big Agnes down bag it has no insulation on the bottom. Instead it has the channel you slide your mattress pad into.
Well this works fine for tenting, but in the hammock the mattress has to be really deflated to make it comfortable and then you lose your insulation on your butt but you get it in the toes.
Well I'm not quite dialed in yet. But I'm working on this tonight because I have another 3 day weekend coming up and need to be prepared since I'll be out in the wilderness again. I plan to take a small piece of closed cell foam, the size of the overhang not insulated by the underquilt, and use some more Climashield Apex 6 oz insulation and sandwich that together.. like 20" x 15". And then put velcro on the edge and inside of my Big Agnes Mystic the mating velcro, and then it will stay positioned and my feet can flop over however and I'll be warm and toasty like how I like to be. That's the plan.
Here's a few photos. The first is the quilt in the middle of the binding. I have two edges bound here and two waiting to be. Second photo is how it looks set up last weekend at Turkey Springs Camp in the Silver Peak Wilderness in Big Sur.
And oh, how warm is this? Well I read a post earlier tonight some guy made a quilt out of two layers of Apex 5 oz, now I don't know where he got 5 oz from but maybe that was a typo. Anyway, he reported his was way too warm at 55 degrees. Well, mine doesn't get hot. It doesn't get cold either. It is that Goldylocks "just right". I've also hung in the warm afternoon sun and no overheating however it is warm to the point of coaxing me to nap like a baby. My first hanging it was low 30's and very windy with Arctic winds coming straight down the mountain tops. In the morning there was frost on much of the undergrowth, and I woke up with a lot of condensation on the top of my bag due to rain the day before. And, excepting my legs where the Mystic SL has no insulation and that overhung the hammock without the underquilt I was warm as can be. And because I didn't have to rely on the inflatable mattress for the Mystic SL, I had the luxury to turn sideways and sleep in the fetal position since I needed a way to keep my lower leg warm. It was so comfortable!! I think I made the right choice with 6 oz on my first quilt. It rarely ever gets below freezing in Big Sur and that's where I spend all my time. This might wind up being a 4 season quilt for me, but if it's too warm I can always make another with the 4 oz Apex or I think they even have a lighter one than that.
How does it compress? Not as well as down. But darn near close when you employ the help of a compression sack. Maybe I need to take more photos and elaborate on that part later.
So far I'm sold on the Apex! I'm going to make a top quilt next! I could do that now but I don't want to use the ripstop I have currently for that. And haven't placed my order for the new fabric yet. But I believe this is the proper weight/thickness and material. I am going to call this quilt a superlight. Not an ultralight but definitely a superlight. Most everything in my pack is superlight or ultralight. Take away the insulated mattress which is heavier than this quilt and I'm bumping up a little in volume but decreasing my weight. It's a great trade-off for me as I also carry bushwhacking materials and photography equipment generally when I go out every weekend.