Underquilt Top and Bottom Question

[kg8jk]

I am hoping to build myself and underquilt but am a little confused how to proceed. Many DIYers have mentions making the bottom layer of the underquilt slightly larger than the top to allow for the curve. That makes sense to me but how do you sew the two together if they are different sizes? I can see how you could sew two sides together and that would be no problem but how do you sew all four together? I am guessing the corners are gathered or folded somehow? Also how much bigger would you make the bottom layer? I am hoping to make a 0 degree underquilt so I am thinking 4" of loft

Anyone have any light to shed on this?

A different question: Has anyone used tulle for baffles? I happen to have quite a bit that I found at a resale.

Thanks
Dirk

[foxrun]

This is only an example... The top layer will have the baffles spaced out every 6", but the bottom layer will have the spacing every 7.5", so there is extra material for loft on the bottom.

[Caminante]

At 4" I'm assuming a down UQ. The UQ calculator (I don't have the link handy, but a search will turn it up on the boards) will give you the dimensions to cut your liner and shell for your stated dimensions of length x width x loft. For the corners, you can just box them as shown in this picture on a synthetic quilt to make the dimensions match the liner, or you could put pleats at the end of each baffle to make them line up. I've only used no-see-um for baffles so I can't comment on the tulle, but it seems like it would work.

[Scoutmaster1056]

Do a search for the Catsplat underquilt spread sheet. You enter in all your information and it will give you the size of material that you need and the amount of down needed to fill it. If you adjsut the numbers in the spread sheet you can see the temperature change that the quilt will be good for.

I did darts in the corners of the quilt to be able to sew the ends together. There is a lot of good information in the DIY section of the forum on doing quilts.

[slugbait]

About the tulle- give it a good yank (in both directions, at the edges). If it tears easily this could happen after the quilt is in use- not a good thing.

[kg8jk]

About the tulle- give it a good yank (in both directions, at the edges). If it tears easily this could happen after the quilt is in use- not a good thing.

Thanks for the replys. I appreciate the help. I will check out the tulle. I know some tulle tears pretty easily. I seem to remember having some of the bad stuff and some of the good. Definitely don't want to do all the work and have things ripping apart.

Dirk

[kitsapcowboy]

I posed a similar question to the guys at Ripstop by the Roll in another thread, with regard to their Climashield Apex synthetic quilt kits. Unlike down quilts, synthetic quilts made from a sheet of continuous fiber batting like CS aren't typically constructed with baffles, so if I wanted to make a differential outer shell, I was advised to cut the outer shell a few inches larger in each direction and then use pleats regularly spaced to bring it down to the size of the inner shell.

However, the exact dimensions and manner in which this pleat technique is implemented is somewhat variable and open to interpretation. In the spirit of "HYOH" there's no really wrong way to do it -- including skipping the differential completely. Several synthetic UQs I've seen from respected and trusted cottage vendors have no discernible differential in their shells, as best I can measure.

As best I can tell, it depends at least in part on the loft of the insulation used in the quilt. Climashield Apex seems to have approximately 1/4" of loft per ounce per square yard of fill. So if you're using CS 6.0 to make a 30-degree underquilt, if you're attempting a differential cut you'll want to account for about 1.5" of loft (1/4" x 6 oz/sq yd) in the insulation between the shells.

If one is using the aforementioned CS 6.0 to make a UQ with a relatively generous finished width of, say, 45", one can roughly model the shape of the UQ shells as two concentric half-cylinders running beneath the hammock body. The inner shell is 45" wide, so wrapped halfway around a roughly cylindrical form, i.e., you, the inner shell would form a half-cylinder with a radius of 14.33" (45 / pi). This means the concentric outer shell would wrap around the inner shell 1.5" further away from that same center line, at a radius of 15.83". Thus, a differential-cut outer shell on a 45" wide synthetic UQ with CS 6.0 fill would need to be at least 49.71" (15.83 x pi) plus any seam allowances. Additionally there would be a personal choice "fudge factor" added to the width of the outer shell, where one could add from 0" to 3" of additional material to the outer shell to account for the thickness of the fill at the edges of the quilt, depending upon whether one wants the edges of the outer shell to be tapered or square. So for this example differential-cut synthetic UQ with a 45" finished width, allowing a generous extra 1" total for the seams, you could cut the inner shell blank to 46" wide, and you would mate that (with pleats) to an outer shell blank anywhere from 50" to 53" and still be in the ballpark, as compared to the same quilt with equal shells and no built-in compensation for the loft of the fill, for which both blanks would be cut to 46" wide before sewing.

Say you decided to do a very modest differential cut on the UQ described above, and you made the outer shell blank 50", 4" wider. By gathering four 1/2"-wide pleats, each spaced 10" apart and taking up a full inch of fabric, you would bring the outer shell width dimension down to that of the inner shell, pinned into place for sewing.

For the length dimension, where there is relatively little curvature, you wouldn't necessarily have to account for the loft, except if you wish to add the same "fudge factor" to allow for a more tapered or squared edge at the top and bottom of the UQ where the cinch channels go. (Most of the quilts I've seen seem to have little to no length differential whatsoever.

The use of differential-cut outer shells in synthetic underquilts seems to be less and less critical for thinner quilts with warmer temperature ratings. I'd say the cut-point for performance versus complexity of the build seems to be between CS 5.0 and CS 6.0. If you're doing a DIY CS 3.6 or CS 5.0 UQ, it's probably more trouble that it's worth to do the differential cut. If you're doing a DIY CS 6.0 UQ, you could go either way without fault. If you're going into colder temps with 7.5 oz fill, where maximizing performance starts to get more critical, I would give serious consideration to the differential. If I were making a deep winter quilt with 10 oz fill, I'd surely do it.

That's pretty much my humble precis of my research, as best I can reckon, in preparation for my own upcoming DIY UQ project. HTH...

[SGregory]

For an APEX 5.0 I didn't worry so much about pleating other than giving the outer fabric more room. ( I added the thickness of the insulation x2 to the outer cover dimensions) I just pleated the ends for a tight fit as seen in the drawing. Worked well for both the the UQ with 5.0 APEX and the TQ Apex 3.6. Like it so much I am building a second, this time aligned with the angle I hang. ( miss thought out the inversion of the cutout when the UQ was pulled through ).

In the down quilt seen in the last two photo's I did have to sew in pleats in the middle of each baffle. The idea being that when you in it together the perimeter is the same for both the outer and inner covers. Not all people do it this way but it is what made sense to me.

APEX 5_0 UQ 001.jpg IMG_3541.jpg
IMG_3378.jpg IMG_3382.jpg
IMG_3404.jpg