DIY Underquilt Question.

[eviscerate3]

Hello all, So my addiction of doing this DIY stuff has gotten me 12 hammocks, 4 tarps, 2 climashield top quilts, a pillow hat, and many stuff sacks and things like that. i have a winter underquilt that i ordered the shell from underquilts.com and absolutely love it. the thing is, I stuffed it with a ton of down and its only good below around 30 degrees. ive decided that i am going to make a new underquilt starting from scratch. The goal is to be able to reach down to 20 degrees. my question is how much larger does the outer shell need to be vs. the inner shell? my plan for the inside shell is 48" x 66". ive read alot of differing opinions about how to do the differential cut and how to measure it out. Does the outer shell fabric need to be wider as well as longer? Ive looked for some plans and cant find exactly what im looking for. i ordered the fabric from dutch and am hoping to get started sewing soon. Thanks for your help!

P.S. i plan on using 2.5 inch baffles if that changes things.

[Boston]

Use CatSplat's calculator here:

https://www.hammockforums.net/forum/...=1#post1317305

The true differential is really only on the width. For length just add your baffle height to each side, and sew the chamber as a "box".

[eviscerate3]

Thank you Boston! When you say to sew the chamber as a box I'm a bit confused. how far from the end ot the shell do i want to sew the baffles? My thought was to run then down the entire length minus the seam allowance and sew the end seams all the to the end of the baffle material. i appreciate your help! Does it matter if I start sewing the baffle material to the inner or outer shell first?

[Boston]

Does not matter which you sew first, but I find it easier to sew the baffles to the outer first.

When I sew a chamber, I sew the outer first, and start by sewing up the short end of the baffle, then the length, then back down the short end at the other end. This creates a "box" shape. Otherwise, near the edges of your quilt, the down will be compressed some.