Layering summer bag and quilt

[Monkeyboy42]

I've got a kelty cosmic cloud 40 that with a fleece blanket and clothing I've used comfortably below 40. I'm making a 40degree 3.6 oz apex quilt for my wife to use in summer.

Any idea how low I could take both together? I'd probably put quilt inside bag and use bag as an over quilt, because the apex doesn't compress as easily. I'm also "over stuffing" the foot ox on the quilt by doubling the Apex.

Underneath I can sling two 3/4 5oz apex quilts with a ccf foot pad.

I'm guessing that I can comfortably hit 20degrees if wearing base layers? Thoughts?

[BillyBob58]

Is the apex TQ(is that right, TQ?) replacing the fleece blanket, or adding to it? If replacing, it depends on how warm the kelty is alone.

If you were able to hit the rated temp in the Kelty, then (speaking for myself and my experience) if there is adequate room inside the Kelty for every thing, then I would expect it to go below 20F. You say you expect the 3.6 Apex to be a 40F quilt. And probably so, since I have taken a 2.5 CS XP UQ to mid to high 40s, no layers, and was warm enough. So if 70F is the point where you need insulation, then 40F Apex would be giving you 70-40=30F worth of insulation.

If all is working perfectly with the layering(no compression or gaps/drafts), adding another 30F to the 40F Kelty should get you 40F-30F= 10F. If your Kelty is not that warm, then just add the appropriate amount to the 10F. So Kelty warm to 59F for you? 50-30F(extra boost from Apex)= 20F. HTHs.

[FLRider]

Also...note that this is going to be functioning as part of an insulation system rather than a stand-alone. If your under insulation isn't good to 20*, your top insulation is unlikely to make up the difference.

Just something to consider...

[Monkeyboy42]

Thanks guys. This is what I thought. FLRider I've got double layer 5ozn apex for bottom as I said in original post. I'm definitely more concerned with the top.

Thanks!