I'm looking to lighten up, but not to give in to much comfort. How do you use a frameless pack with an air core pad, like the big agnes insulated air core of poe ether pads ? Do you use a sit pad or something as frame ?

I use a self inflatable 3/4 length pad (thermarest or other brands), fully deflated and folded in 4 as packframe, in totally frameless DIY packs (into a special "inner "slieve"). Enough support, and comfortable up to 10/11 kg, only drawback is the pack tends to "stick" closely to my back, not very pleasant in hot weather. The back part of the pack has 2 extra vertical pieces of padding which help a bit for "aeration".

I've been looking into that, and from what I have read a common method is to fully deflate the 3/4 length "thermarest" closing off the valve and then after folding and inserting the deflated pad, to let some air back inside. People mention finding the "right" amount of air to inflate it for best performance.

Um, I don't think you can use an air core pad as a virtual frame in a frameless ruck. There's no "there" there. No structure = no support.

I don't think the insulated air core pad from BA can be used for an internal pack "frame." It's an air mattress, not a self-inflater; there's no foam core.

“Do you use a sit pad or something as frame ?”

If using an air core pad, I think you hit upon the solution.
For the Mariposa, I use the Sitlight http://www.gossamergear.com/cgi-bin/gossamergear/sitlight.html at 1.4oz. I am surprised how comfortable the pack is using this at 20lbs. A big comfort help was when I took the support poles out of the pack.

For this to work, it helps to have a pad pocket to keep the ‘frame’ in place.

-Barry

Depending on your load and your pack, you may not need anything.

I am able to pack my pack in such a way that it keeps it's shape, and is comfortable to me up to around 30 pounds. I carry a ULA Conduit with no pad as a frame.

Another way to solve the problem: (1) Get a dog. (2) Get a sleeping pad for the dog. The Gossamer Gear NightLight torso length sleeping pad is just right for my 80-lb. mostly Lab (who sleeps curled up in a ball). The SitLight would work for a smaller dog. (3) Use the dog's pad to support your pack and give the dog a 3-oz. item of yours to put in his pack. You thus have excellent support for your frameless pack with no extra weight!

Personally i'm a cat person <img src="/forums/images/graemlins/smirk.gif" alt="" /> Pad would be to small <img src="/forums/images/graemlins/laugh.gif" alt="" />

I'm guesstimating here but i'm a little under 6 pounds for the big 4 (pack, pad, sbag and tt) so i'll keep it under 15 most of the time with a couple of days worth of food. Most of the time i carry my water at the front, attached to a pack-strap.

You can see my dog's pad on the top: a Gossamer Gear Thinlite. It also makes a great sit pad.