New sewer needs help

[Guinea Pig]

Hello,
I have used this forum for years, and love all of the information it has. Up until now I have been able to figure out what most people are talking about. Well, that is, before I received my first sewing machine! I have been trying to figure out how to do some of the bigger projects, and had some questions that I'm sure are rather obvious, but I'm having a tough time visualizing them.

First, I was looking at underquilts/ top quilts that are differentially cut. From my understanding, it seems that most people cut one size smaller than the other, and effectively use pleats to make them the same size as the project continues on. My question is, why? What exactly is the point of making them different sizes if they are going to become the same size in the end. Maybe my confusion lies in what a pleat actually does, but maybe someone can shed some light on this. From what I can gather, making them differentially cut doesn't compress the insulation, but how can this be when the sizes become the same in the end?

Second, I like the look of this top quilt (https://www.youtube.com/watch?v=eKn9wsM8--U), but there is a point at 6:17 that I am unsure about. It looks like he sews the ends into a bathtub floor (would love to know the exact name of what he is doing), and then attaches the bottom shell to the top shell. My question is this, if I am going to do a design like this, should I be doing the exact same "bathtub floor" effect on the top shell as well, and sew the two together after sewing the baffles, or should I cut the topshell into a rectangle and sew it directly onto the bottom shell which is essentially a "bathtub floor". If I do just sew a rectangle onto the bottom "bathtub floor", then should the dimensions of the rectangle be the same as the bottom shell before it was cut, or the dimensions after the "bathtub floor" was added?

Lastly, what is the difference between a pleat and a dart?

Anyway, I don't actually plan on doing any of these projects anytime soon. I would just like to get the concepts down so that I can maybe think long and hard on the designs, and possibly do one myself.

I appreciate your time,
Thanks!

[FLScouthanger]

Guinea Pig,

Check out the UQ build plans at this link--it might help you understand "why" pleats/darts are needed/useful...

https://hammockforums.net/forum/show...UQ-Build-Plans

[Ramblinrev]

Lastly, what is the difference between a pleat and a dart?

Generally a pleat is a fold in the fabric that maintains it dimension for the length of the feature. Think a kilt. The pleats run the length of the fabric and generally are the same width all the way. A dart is a triangular feature that ends in a point. If you take the stitches out of a dart the needle holes will be in a triangular shape. It is generally used for forming contours and shapes in the flat area of the fabric. If you can get your hands on a women's tailored blouse you will likely find darts that form the bodice shape consistent with the feminine anatomy.

[doogie]

The differential is needed since when you wrap your underquilt around yourself, the outside of the quilt is longer than the inside. The red line is longer than the gray one. differential.jpg
The darts are needed because the ends of your hammock (and you) taper down.

[Guinea Pig]

Hello everyone!
I'm sorry about not responding right away. I had to take a step back from DIY projects, and focus on school (DIY projects are just too entertaining!). I appreciate all of the feedback, and I think I have the right idea, but I would like to see if I'm on the right track. Am I right to assume that if I differentially cut two pieces of fabric, and intend to sew them together, then I will need to take care of the extra length or width, and make it the same length/ width as the other piece? I hope this makes sense, but essentially I am wondering that if I take a rectangle that is lets say 44 inches by 72 inches, and another that is 48 inches by perhaps 74 inches, then I will need to make the bigger piece 44 inches by 72 inches? And, to expand upon this further, the methods I may employ to "take care" of the differential cut could be darts, pleats, tucks, and so-forth? Either way, I must employ SOME method to make the two pieces of fabric the same, right? If I'm off track here, then please let me know, but I hope this is close. Trying to visualize a 2D object in 3D isn't easy, lol.

[Ramblinrev]

The idea of a differential cut is to make one layer of the fabric larger than the other. This introduces an air space between the two layers. This airspace keeps the insulation from getting squashed under pressure preserving the loft and therefore the warmth. There are several ways of bringing the edges into alignment. My own personal favorite is a "gather" which is a third structure besides pleat and dart. A gather is where you take the excess material and squish it up along the seam line. A dart would be used to make the ends of the quilt taper into a smaller width. Not so much to bring the edges into alighnment. You could do that with pleats, but I think a gather is easier and faster but that's personal preference.

[Brewguy]

Hello everyone!
I'm sorry about not responding right away. I had to take a step back from DIY projects, and focus on school (DIY projects are just too entertaining!). I appreciate all of the feedback, and I think I have the right idea, but I would like to see if I'm on the right track. Am I right to assume that if I differentially cut two pieces of fabric, and intend to sew them together, then I will need to take care of the extra length or width, and make it the same length/ width as the other piece? I hope this makes sense, but essentially I am wondering that if I take a rectangle that is lets say 44 inches by 72 inches, and another that is 48 inches by perhaps 74 inches, then I will need to make the bigger piece 44 inches by 72 inches? And, to expand upon this further, the methods I may employ to "take care" of the differential cut could be darts, pleats, tucks, and so-forth? Either way, I must employ SOME method to make the two pieces of fabric the same, right? If I'm off track here, then please let me know, but I hope this is close. Trying to visualize a 2D object in 3D isn't easy, lol.

yes this is correct. The very edge of the fabric has to be the same size in order to sew them together. This does effect loft but only on the very edge of the quilt.

[Guinea Pig]

The idea of a differential cut is to make one layer of the fabric larger than the other. This introduces an air space between the two layers. This airspace keeps the insulation from getting squashed under pressure preserving the loft and therefore the warmth. There are several ways of bringing the edges into alignment. My own personal favorite is a "gather" which is a third structure besides pleat and dart. A gather is where you take the excess material and squish it up along the seam line. A dart would be used to make the ends of the quilt taper into a smaller width. Not so much to bring the edges into alighnment. You could do that with pleats, but I think a gather is easier and faster but that's personal preference.

Do you mind elaborating on this method a little more? I'm envisioning a series of tiny darts, but instead of sewing it down the hypotenuse of the dart, you would just sew on the short edge at the edge of the fabric? Is this a correct assumption, or do I have the wrong idea? Also, do you use any math to "take care" of the differential cut, or just visually append the two pieces together using the "gather" method? I think I would much prefer this method to mathematics, if this is the case.

[Ramblinrev]

You have generally the correct idea. Making a gather involves a few steps which may seem cumbersome, but are quite easy to accomplish once you understand them. First loosen the top tension a few clicks. Not so much as to make a rat's nest but enough that the loop is not fully tightened. Use the longest stitch length (a basting stitch) along the piece you want to shorten. Only one layer is involved here. Stitch the basting the length of the gather about 3/8" from the edge and cut the threads. Leave long tails on each end of the stitch line. Grasping the the bobbin thread and the fabric, slide the fabric along the thread so it puckers up along the way. Distribute the puckers evenly along the length. Pin the pieces together lining up the edges. Sew at the usual 1/2" seam allowance using a normal properly balanced stitch. Remove the basting stitch when the seem line is complete. Voila. It took longer for me type that than it takes to do the technique.