Sewing first vs. serging first
There is some argument about this in the sewing community, and I think it depends mostly on what you’re sewing and personal preference. When in doubt, experiment, and find what works best for you.
Sew first, then serge: I think this would be a good place to start if you’re a serger noob. A serger does take some adjustment when sewing. Because the machine cuts the seam allowance off as you sew, you’ve got a lot less room for error.
I sew first when I’m assembling awkward seams. It’s a lot easier to keep the fabric where you want it when you’re serging if you’ve already stitched it.
This would also be a good technique if you’re sewing something like a woven fabric that doesn’t need the stretchable seam that the serger allows, but you’d still like a finished looking seam.
Serge first, then sew: I use this technique sometimes when I’m sewing a zipper or a slit into something, and I won’t be able to have a serged seam. I serge the edges of the fabric, then sew the pieces together, so I still get a professional looking edge.
Serge, then topstitch: This is the technique I use most often. I serge the seam, then I press it to one side and stitch it down from the right side of the garment.
I don’t topstitch all of my serged seams, but most of them. Some things are too bulky to topstitch, so I just leave it.
Straight stitching for reinforcement: There are a few kinds of fabrics and garments that absolutely require that you straight stitch AND serge the seams. I don’t even bother trying to serge very loosely woven fabrics. The serged edge will fray right off.
Bags need not be serged, since ideally all of your seams will be hidden by a lining. If you do make bags and want to serge the seems, you must straight stitch as well, as a serged edge is not strong enough by itself to hold weight.
The crotch seam on a pair of pants MUST MUST MUST be straight stitched at least twice if you’re using a serger, or I guarantee you will be feeling some interesting drafts… I also like to straight stitch the armpit seam of shirts after serging.
I’ve found that I need a much smaller seam allowance when I’m serging my seams. I generally use about 1/4″ seam allowance when I’m serging, vs. a more standard 1/2″ or 5/8″ seam allowance. You will find what you’re most comfortable with, just keep it in mind when you’re cutting the pieces of your garment out.
What is the difference between overlock thread and normal sewing thread? Should I use only overlock thread with my serger?
Overlock thread is not made to be as strong as normal thread, so its cheaper to buy in those big spools. You can use normal thread in a serger, but it’s a lot more expensive and unnecessary. You’ll probably run out in about 20 minutes. You probably don’t want to use overlock thread on a regular machine unless you’re having one of those out-of-thread-at-midnight emergencies, because it isn’t as strong.
Hemming with a serger
I personally don’t mind the look of a plain old serged edge as a hem. Use a contrasting color and it kind of looks like the hem has some sort of trim at the edge.
If it’s something that wouldn’t look right with the serged edge, serge it (or don’t), press the bottom 1/2″ or so under, and just stitch around it like you normally would hem something. If you don’t like the look of a straight stitch, you can use a zig-zag or another decorative stitch. Do it in a contrasting color and no one will think you were avoiding hemming it!
Some machines come with a hemming attachment, I only used mine once to test it out… I’m too lazy to switch the footplate and the foot and the settings everytime I want to hem.
Why does the serged hem of my knit garments turn out all wavy and stretched out?
You need to adjust the differential feed. On most machines it’s probably numbered 0.7 to 2.0. If you serge the edge of something really stretchy with the diff. feed at 0.7, it will make a “lettuce edge”.
If you take some non-stretch fabric, and serge the edge with the diff. feed at 2.0, it will actually ruffle it for you, which is kind of cool.
If you want the serged hem of something stretchy to not get all wavy like the lettuce edge, put the diff. feed a few clicks closer to the 2.0. Some knits I can do fine with on the normal setting (1.0), but if they’re pretty stretchy, I’ll go one or two clicks towards 2.0. If they’re really really stretchy, I go even further towards 2.0.
It takes some messing around with to get it right, but once you get the hang of it, it helps a lot.
What kind of needles should I use in my machine?
Check your manual for this, as it differs from machine to machine. Using the correct needles in your serger is just as important as your regular sewing machine.