So I got some Lastin since I think one of my sons is sensitive to reg elastic. I know he is def sensitive to PUL!!
So I am trying to whip up a new stash for him but I feel like I am sewing it all wrong...
I tack down the end by folding 1/2inch in half and tacking with the zig zag, then I back stitch tack again and start on the 3-step zig zag all the way down but its SOOOOOO slippery!! So in some spots I am only sewing half of it down because its slipping off the diaper etc and it is agravating me because I think this is going to affect the lastin, maybe causing it to snap down the line... IDK tho
So my question is, What is the right way to sew lastin? What are the things to avoid doing to lastin? Tips please!! Before I sew my whole stash wrong!
Some tips I found here. As for the slipping, the best I can offer is to sew slow until you get the right feel for it, or lengthen your stitch. HTH!
BREAKAGE
I've had some breakage way back in the beginning and it sucks... really really disappointing. So, I did some lastin sewing on some scraps so I could see what was happening. I discovered that holes were forming where my needle went through the elastic. Okay, there's not really a way to avoid that.. needle=holes right? While we can't avoid putting holes into the lastin, we can keep those holes from growing so big that the elastic actually breaks.
After a lot of experimenting, I found that how hard I pulled the elastic was directly proportional to how big those holes would become. Fortunately, you don't get much benefit from stretching lastin more and more. It'll create a great gather without using any muscle.
HOW MUCH TO STRETCH
I tend to do this "by feel" now and most people who have luck with lastin sort of have a feel for it. But, before I had a feel for it, I played around to figure out just how it should feel.. too much? not enough?
First I started by testing my lastin. I'm going to give the example of using 5 inches of lastin. That stuff will stretch 15-18 inches if I fully stretch it!! But, if I fully stretch it, there's a really good chance it'll break, and a good chance it'll be too tight.
So how much should I stretch it? Slightly more than double. My "formula" is this--
I start stitching in the inseam with no elastic so I can do my backstitches (more on this later.. never backstitch on lastin) then I start the elastic (folded over a little for strength) BEFORE the elastic mark and without stretching it (this is how I tack down so I can have something to stretch against). Then, I know, for example, the sewing length of the leg elastic will be 11 inches from mark to mark. I'm giong to grab the elastic at about 5 inches from the needle and stretch it all the way to the other elastic mark. I'm making the elastic stretch slightly more than double. If I need to cover the 6.5 inches across the front, I'd grab it at about 3 inches from the needle... slightly less than half of my total length.
I know this isn't exact, but in diapers, we're working with fairly small lengths and if you end up stretching a tiny bit more or a tiny bit less, it's not going to matter. Just grab the relaxed elastic at slightly less than your total sewing length and stretch it to that length. Do this a few times and close your eyes and really feel it. Once you get a feel for it, you won't even bother with measuring.
HOW MEASURE ON THE FLY
So when you think you've gotten the feel of things and you are confident you aren't overstretching your lastin, you'll probably want to just do things by feel. But, for some reason the legs keep coming out uneven. This can happen for two reasons. First is you forgot to pre-stretch your elastic -- we'll talk about that in a moment. But the other is simply that with the diaper facing the other way, you are stretching slightly differently from one side to the other. The way to avoid this is to mark your elastic at every inch with a little dot. Then sew the first leg as you normally would by doing what feels right. Then, use those dots to figure up exactly how much elastic you used. Mark that length onto your elastic for the second leg (no need to mark every inch.. just one mark will do) so you can be sure your legs are using the same amount.
PRE-STRETCHING
Lastin really benefits from a good pre stretching. Just take your elastic and stretch it real good a few times before you even think about sewing with it. This does tend to lengthen the elastic slightly so if you forget to do this, you might end up using less elastic and overstretching it when you sew. Pre-stretching also loosens the elastic up a bit and it will feel different so if you are stretching it by feel when you sew, it helps a lot to pre-stretch it.
NEVER BACKSTITCH LASTIN
After unpicking the stitches to fix broken elastic for the 5th time, I noticed that at least half of the time, the elastic was broken right by my backstitches. It's so ingrained in me to start elastic by stitching forward and then back and then forward and back and then forward again that I STILL find myself trying to do this with lastin. If you do too, start over. Backstitching creates too many holes in this thin elastic and that end will be too weak to hold up against all the tension. (ever feel like that??)
So if we don't backstitch, how do we tack down the end? Start your needle about an inch before your elastic mark (I'll assume you are working in the seam allowance, but this works for blind elastic too). Without any elastic, start sewing and do the necessary back stitches. Now you are still about 1/2 inch from the first elastic mark. fold the end of your elastic over onto itself a little and place this folded end under the needle. DON"T stretch and do not, for goodness sakes, back stitch. Just sew until you reach the elastic mark. Now your elastic is tacked down so you can lightly begin to stretch your elastic. For the first inch, be a bit gentle with your stretching and then stretch the amount you feel is right. When you reach the other mark, taper off on the stretching as you approach it. Cut your elastic so there's a 1/2 inch tail past the elastic mark. Sew over this tail just like you did to start.. without stretching and without backstitching on it. When past this mark, do your backstitches to lock the stitches.
WHICH LASTIN AND WHICH STITCH
Here is my disclaimer. My lastin might be different than yours. I hear there are different thicknesses and I have no idea what thickness mine is. You may find that your lastin needs to be stretched more or less. The real lesson here is that you don't need to stretch the lastin hard, or even fully for it to do it's job and that if you've had breaking lastin, it's probably because of overstretching.
I have both 1/4 inch wide and 3/8 inch wide. I prefer the 1/4 inch for diapers that are made from layers that aren't too bulky. The 3/8 inch works better for fabrics that are thicker. 3/8 inch doesn't have more gather in my opinion, but it's stronger which means it's not as gentle on thighs.
I think the only way to correctly sew lastin is with a 3-step zz. If you don't have that stitch, you are missing out. It's basically a "stretch" stitch that allows the thread to have lots of movement so it doesn't "saw" holes in the elastic. Never use a straight stitch on lastin because it'll cause it to tear and break.
I like to use the widest setting my machine has which is a 6mm. For length, I find somewhere between a 3 and 4mm works well... anything shorter tends to cause too many holes in the elastic
HOT LASTIN IS WEAK
Try not to stretch lastin while it's hot from the dryer since it's weaker then and the needle holes are most likely to grow and cause breakage then.
That's it.. that's all I have. If you made it through the entire thing, you should be commended I'm sure others will chime in with their own tips or experiences or formula for how much to stretch lastin.
happy sewing!!
edited to add -- If you are worried about breakage etc, make pocket diapers (without casings) for your first few trials. That way, you can keep an eye on it and replace it if it does break
My First Newborn Diaper!
- Sunnyspot1118
on Nov. 25, 2009 at 2:31 AM