Costco Underquilt Question/Idea - Faux Baffles?

[-c0de-]

I snagged two of the Costco Down Blankets, and they should be arriving in the next few days. In the meantime, I have been researching the best way to turn one of these into the best underquilt possible. Besides the obvious improvement of ripping all of the horizontal seams to allow for individual vertical chambers instead of multiple sewn-through squares, here is what I have in mind. Since this will be my first DIY UQ, I am hoping some of you fine folks with more knowledge than me could tell me if it would be worth it or not to do the following.

The first idea was since these throws are 60" x 70", that means that I could take two rows off of the 60" side, which would leave me around 50", much like in this photo:

AsrACiU.jpg

I could then take the two extra rows, and attach them as draft collars at the top and bottom of the underquilt, using the extra squares' down to overstuff the collars. I figured that should help keep the heat loss to a minimum, and maybe help to eek out those few extra degrees.

My next idea comes from seeing how most underquilts have baffles of some sort, and that typically the inner shell of an underquilt is smaller than the outer shell. Using the DIY Differential Cut UQ Calculator, it seems like adding a 1 inch baffle reduces the inner shell dimensions by roughly 20 inches. This means if I sewed together one inch on both sides of each chamber, it would give me a faux 1 inch baffle, and should help to reduce the amount of heat that escapes through the sewn-through portion of the underquilt. In turn, I think this means that the overall chamber height should be slightly increased since it would cause the underquilt to naturally round out more, allowing the down to loft better, increasing the overall heat retention. This is all assuming that I leave the blanket at its original size and didn't remove any rows for baffles. (While it would just be easier to stitch in a secondary blanket .vs. the time and effort to sew in faux baffles, GadgetUK437 has done exactly what I was suggesting in a display of parallel discovery: Costco Differential Cut 3/4 UQ with Faux Baffles.)

Do these mods sound correct? Am I attempting to accomplish too much with a cheap DIY Costco Underquilt?

Thanks~!

[sqidmark]

Just a few days ago I did as you suggest, using the cut off rows to create draft collars. I took a single row, cut to my desired length, folded in half lengthwise, sewn onto the joining edge to effectively create a tube. Sew the tube to the channel seam.

Not a very good photo, but you can see it in action. The collar is filling in where the calf ridge is.
draft-collar-on-hammock-foot.jpg

I admit it, I'm completely baffled by your baffle idea.

EDIT: I also made this with 3 darts at each end tapering the width from 45" to 32".

[-c0de-]

Awesome. I'm glad to see that the baffle idea is realistic. Seems like a very easy mod to add, that should also be beneficial at the same time.

As for the faux baffle idea... I may just have to run with it and see what the outcome ends up being.

[wiredconcepts]

I snagged two of the Costco Down Blankets, and they should be arriving in the next few days. In the meantime, I have been researching the best way to turn one of these into the best underquilt possible. Besides the obvious improvement of ripping all of the horizontal seams to allow for individual vertical chambers instead of multiple sewn-through squares, here is what I have in mind. Since this will be my first DIY UQ, I am hoping some of you fine folks with more knowledge than me could tell me if it would be worth it or not to do the following.

The first idea was since these throws are 60" x 70", that means that I could take two rows off of the 60" side, which would leave me around 50", much like in this photo:

AsrACiU.jpg

I could then take the two extra rows, and attach them as draft collars at the top and bottom of the underquilt, using the extra squares' down to overstuff the collars. I figured that should help keep the heat loss to a minimum, and maybe help to eek out those few extra degrees.

My next idea comes from seeing how most underquilts have baffles of some sort, and that typically the inner shell of an underquilt is smaller than the outer shell. Using the DIY Differential Cut UQ Calculator, it seems like adding a 1 inch baffle reduces the inner shell dimensions by roughly 20 inches. This means if I sewed together one inch on both sides of each chamber, it would give me a faux 1 inch baffle, and should help to reduce the amount of heat that escapes through the sewn-through portion of the underquilt. In turn, I think this means that the overall chamber height should be slightly increased since it would cause the underquilt to naturally round out more, allowing the down to loft better, increasing the overall heat retention.

Do these mods sound correct? Am I attempting to accomplish too much with a cheap DIY Costco Underquilt?

Thanks~!

I did this exact thing, I will take some pictures when I get home so you can see how I did it. The mods worked perfectly.

[kitsapcowboy]

Parsimony may be the key here; since you have two throws, and since the sewn-through design is the most likely weak point in the thermal performance of the Costco down throws, applying Occam's razor, it would seem that simply staggering the Costco quilts might be better than designing baffles into one throw, if you are willing to turn two down throws into one underquilt. Cut a section off each side of the first throw (reducing its width by two sections) to use as draft collars, and then trim the second throw asymmetrically to the same width and apply it to the first as an additional layer of insulation, so that the peaks in one throw mate with the valleys of the other, providing more even insulation over the entire area of the underquilt. You could even trim the inner layer throw by a couple of inches to introduce a bit of differential to maximize loft. In the end, you ought to be able to create an easy-to-build underquilt that is warmer than one made from two throws stacked congruently as well as anything you could make from a single throw, even with the introduction of differentials, baffles, or collars.

[brianb]

Parsimony may be the key here.

Good word. I should change my screen name to Parsimony. I always struggle with whether I make so much of my gear because I enjoy it or because I'm a cheapskate.

I've seen someone take two of these and stagger them similar to Kitsapcowboy's suggestion. Seemed to work well, he wasn't yet aware of the lower temp limits of his setup.

[Carbon]

What I did for my WBRR diy UQ is that I added a single, narrow liner over the inner shell to create the differential.

[Duncanslam]

I tried that exact thing.

Creating the draft collar worked and is a great idea.

I think what you want to accomplish is pinching the seam together and somehow adding a seam (there would be a bump) such that you have psuedo baffles. I thought this might work but you quickly run out of width and will find that your UQ will be too narrow. You've also put in enough work to warrant just building a baffled UQ from scratch by harvesting the down from the Costco quilt. Now THAT may be your best bet.

I also second the idea of simply taking another quilt and layering it so that the baffles are staggered.

SD

[dbass]

it seems like adding a 1 inch baffle reduces the inner shell dimensions by roughly 20 inches. This means if I sewed together one inch on both sides of each chamber, it would give me a faux 1 inch baffle, and should help to reduce the amount of heat that escapes through the sewn-through portion of the underquilt. In turn, I think this means that the overall chamber height should be slightly increased since it would cause the underquilt to naturally round out more, allowing the down to loft better, increasing the overall heat retention.

If I'm understanding you right, you are saying that after you seam-rip all of one direction of the blanket, creating horizontal or vertical tubes/channels -- that you would then sew each of those together, one inch above the sewn channel remaining. Is that right? If so, like you mentioned you'd be reducing the width by 20". I haven't done a DIY underquilt (yet), but that seems a bit too much of a differential between the top and bottom layers. Is there usually that much of a difference in length between top and bottom layers?

Below is an illustration of what I think you were saying...Its no Dejoya, but I think it shows what I was picturing from your description. Is that about right?

CDT - Faux Baffles (1).jpg

[sqidmark]

...simply staggering the Costco quilts might be better than designing baffles into one throw, if you are willing to turn two down throws into one underquilt. ...so that the peaks in one throw mate with the valleys of the other... You could even trim the inner layer throw by a couple of inches to introduce a bit of differential to maximize loft...

This is exactly what I have planned for this weekend. Will be attaching the outer to the inner with kamsnaps to make it modular. I made the inner 45" wide, but rather than use all kinds of sophisticated arithmetic to figger out how wide to make the outer, I'll hang it temporarily from the inner with some clothespins and a warm body in the hammock. Should tell me all I need to know.

It's nice to know I'm not the only one baffled by the baffle idea. I think if I were going to do that much work, I'd rather just start from scratch, and have something much better in the end.