MYOG Sleeping Pad / Backpack Frame/Back Pad

I did a similar thing with a pad from Gossamer Gear. Instead of duct tape to hold the pads together, I used 1 1/2 or 2 inch "hook" velcro to bridge the gap. I put self-adhesive "loop" velcro on both sides of the gap on the smooth side of the pad. This gives me more flexibility in using the pad(s) as sit pads, or how much pad to take on a trip. You can also make the pad less bulky by interlocking the curved sides together.

Scott,
Velcro makes sense if you are changing the length of the pad. Have you had any trouble with the sections staying together when you are sleeping on the pad (from moving around)?

As you can see in the photo, I was able to get the curved sides to mate together, and since I didn't cut all the way through the pad, they never move on me. The strips of duct tape are there simply to reinforce the joints to they don't separate.