I have been working on a baffled Karo Step down quilt, aiming at a 5-10 deg F rating, so about 3.75 inches of loft.
However, I made a mistake with my baffle height, and sewed them all in, then realized they were 2.5 inches in height, instead of the 3 I had planned.

What loft should I be aiming for, given 2.5" baffles? I want the bag to be as warm as possible, but don't want to over compress the down.

Thanks

Put the same amount of down as if you wanted 3.75 inches of loft. That would be overfilling 50% which isn't that extreme.

Even though the loft doesn't increase, the warmth will be increased, maybe not quite as much as if the loft had increased.

There's a bunch of factors like down quality, how wide your quilt is, how long etc, but you'd want about 20oz of 800fp.

So 3.75 inches of loft is not too much to pack into 2.5" baffles?
I will do some area and volume calculations, but I think 20oz is more than I planned for (although I do have it).

Thanks Guys,
Adie

I can't recall where I saw this figure, but someone once posted that the height of the karo baffles should be anywhere from 2/3 to 3/4 of your planned loft.

In your case, 2/3 of 3.75" comes in exactly at 2.5". As others have mentioned, just fill according to your original plans. The compression will come nowhere close to reducing thermal value, and will assist in keeping the down in place within the karo baffles.

I'm currently in the same boat, planning wise. I'm going to make a 2.2" summer quilt with 1.65" high karo baffles.

A good place to do some basic research is Tim Marshall's site @ http://enlightenedequipment.com/revelation.html. He uses the same 2/3 loft/baffle height ratio.

Edited by Hobbesatronic on 01/19/2012 16:54:11 MST.

Hey Hobbes,

I've recently got the itch to sew my own quilt. Do you have any plans that you are going off of for this summer quilt?

Any idea of the pack size and weight using 800-900 fill down? Very much appreciated!

Cheers,
Corey

Ok, 3.75" of loft it is.

Also, I did some area/volume/fill power calculations, and that puts me right at 17 oz of 800fp down.