Baffle height

[outdoor]

This should help.....
Shug

Attachment 179579

Does it not depend on how much down is in the baffle?

2.5" height with 2.09oz / baffle overall say 23oz of down
3 " baffle height with same amount of down/baffle and overall

Which will be warmer? how much will down be compressed at 2.5"? But will it not prevent down shift and cold spots?

I struggle with these specs as well to determine proper baffle height.

Using Catsplay underquilt Calc i plug in these numbers and get the same temp rating. Obviously, i don't think that is correct. Or is it?

[Shug]

Does it not depend on how much down is in the baffle?

2.5" height with 2.09oz / baffle overall say 23oz of down
3 " baffle height with same amount of down/baffle and overall

Which will be warmer? how much will down be compressed at 2.5"? But will it not prevent down shift and cold spots?

I struggle with these specs as well to determine proper baffle height.

Using Catsplay underquilt Calc i plug in these numbers and get the same temp rating. Obviously, i don't think that is correct. Or is it?

Regrets as I am not mathy and just wing it by feel. I have only made one UQ and added a bit more down than called for. I wanted it to be good to 20º.
Maybe someone else will chip in with good specs or start a thread and ask and you will get a lot of answers to that.
By the way my DIY UQ is nice and warm. I did not stuff the baffles to the max but just to where the down did not seem to shift around.

[lorazepam]

Regrets as I am not mathy and just wing it by feel. I have only made one UQ and added a bit more down than called for. I wanted it to be good to 20º.
Maybe someone else will chip in with good specs or start a thread and ask and you will get a lot of answers to that.
By the way my DIY UQ is nice and warm. I did not stuff the baffles to the max but just to where the down did not seem to shift around.

You didn't happen to video any of that, did you?

[Shug]

You didn't happen to video any of that, did you?

I did not as I had no idea what I was doing but just went for it!

[Cruiser51]

Using the calculator is really good for layout, but the temp rating say "Experimental" and they really don't seem to work very well. The temp rating is pretty much just how thick the down layer is .... the calculator will tell you how much you need to fill the chamber you enter and that down will be pretty loose and can be moved and not distributed evenly creating cold spots.

Adding "Overfill" will address the looseness and any variations in the FP of the down, usually the cottage vendors use ~25% ... be aware with the Catsplat calculator for temp ratings, it is based on the quantity of down and I believe that is wrong, it is the depth of the chamber, or in the case of the calculator the average loft. So if you add overstuff to the calculator, it will increase the temp rating, which is in error IMO

To answer your question, after you have sufficient down to fill the chamber, more down does nothing to the temp rating until you get to somewhere north of 50%+, where it will start decreasing due to compression.
3" will be warmer than 2.5" every time ....

Use the calculator for baffle height, average loft, layout parameters and down per chamber ... compare the average loft to the below chart to get the temp rating as i don't think that portion of the calculator has ever passed the experimental stage

This table gives a summary of what the various vendors are using for temp ratings

Down Information Table
Imperial		Metric
Degrees F	Loft Height (in)	Loft Height (cm)	Degrees C
40	1.5	3.81	4.44
30	2	5.08	-1.11
20	2.5	6.35	-6.67
10	3	7.62	-12.22
0	3.5	8.89	-17.78
-10	4	10.16	-23.33
-20	4.5	11.43	-28.89

[lorazepam]

I did not as I had no idea what I was doing but just went for it!

Somehow, the thought of Carl stuffing feathers into a tube is entertaining.