Hello all,
I'm working on my first adventure into using down. I've bought the thru hiker kit and have read Roger Caffin's fabulous article. I'm a little confused over what is best for working out the baffle height. I'd like the overall loft to be 1.75 inches - so I was going to work out the weight of the down by using the length x width x height / fill power of the down and then add 10%. Question is, if I want an overall loft of 1.75 inches should I make my baffles this size or slightly smaller?

Thanks Kirsty

I like the way Joe @ Zpacks describes how they calculate both baffle and (over) fill loft:

900 Fill Power down means that one ounce of down should fill up to 900 cubic inches of space. Our 20 degree bag for example has a baffle height of 2.25", however it is filled with a calculated loft height of 2.925" (30% more than the baffle height) to account for any future loft loss. It will also have more than 2.25" loft between baffles. Our 30 degree bag has a baffle height of 1.5" but is filled with a calculated height of 1.95" (30% extra).

Zpacks

Tim @ Enlightened also has a nice chart showing all his size dimensions & (over) fill options:

Enlightened

I usually cut the baffles to to the baffle height I want. Using up .25 or so on each side shortens them enough to manage the down well (I also usually overstuff ~20-30% over the caculated need).

Edited by brendans on 02/22/2012 08:38:15 MST.

The specs on enlightenedequiment can help you
I think that 1,25 inch is a safe height (it depends a bit on the distance between the baffles and the % overfill)
In my quilt , with a inch 1 baffle height, I measured 45 mm (about 1,75 inch) but in my case with a 100 percent overfill (400 gr down)
In my (flemisch) blog you can see a few photos how I made the baffles
edit: I used a differential cut for the baffles!!

Edited by Ivo on 02/22/2012 08:45:53 MST.

What about baffle width?

I have this idea that if, for example, your baffles are 2 inches loft, then the baffle width should be 2 or 3 X - 4 or 6 inches

If you're 1 inch loft, baffle width should be 2 or 3 inches

If you're wider, then thin spots will develop where there's no down

Does anyone have experience with this?

Jerry,
my thoughts (For what it's worth.)
you must not economize on the down
overstuffing avoids this problem partially.
I copy from the manufacturers

Hi All - thanks for your help this is great. Ivo your quilt looks fantastic