I haven't done a lot with knits other than lycra - and I love sewing with it. Kat is right - an overlocker is your best friend when working with knits - don't think I would even give it a whirl without one.
There must be something on UTube about sewing with knits????
I have sewn knits without an overlock or serger machine--these machines bind the edge, but often don't add any stretch, so don't feel you can't sew knits with your regular machine.
To start, DO get ball point sewing machine needles so your sewing lines won't have skipped stitches. Sew with a medium stitch and "ease" or pull you fabric a bit as you sew, that will build the stretch into your seam line.
Don't worry about finishing the seam allowances. But if they bother you, after sewing the straight stitch seam line, run down the cut edge with an overcast stitch of wide zig-zag to create a finished edge.
Hems can be folded up and top stitched with a double needle--this will produce a double seam that looks and behaves alot like a cover stitch seam line (check the hem of most T shirts to see this). It is also OK to sew a neat single needle top stitch line on a narrow hem.
Stabilize zipper seam lines and side slits with a strip of fusible interfacing (tricot or knit interfacing works best) down that edge, so the fabric won't ripple when you sew in the zip.
One bit of advice about copying that dress: be sure to duplicate the amount of stretch in your dress fabric. Do this by folding a cross wise section of the skirt. Hold the fold with both hands 6" apart against a ruler, now stretch this width and measure how far that fold will stretch. When you shop for fabric you will want that same amount stretch.
have fun, knits are an easy fit and quick to sew!
Ball point needle
Sew with a tissue paper/newspaper under the knit fabric to stop it from getting pulled.
People also say to use crooked zig-zag stitch for stretchability, but it never worked well for me.
I just use the regular straight stitch and dont have any issues.
Another suggestion I got was to flip the feed dogs switch so that they go down and don't pull the fabric,
again didn't work on my machine. I couldn't get my feed dog switch to flip, not sure if its my machine or me.
Good luck, its great to get out of comfort zone and try knits, they are fabulous and once you start sewing
you wouldn't want to go back to wovens.
I too have never used a serger on knit although it seems like a natural.
I was taught to enlarge my stitch length just a little to accommodate the stretch of the fabric. If you do a little test, by pulling the fabric to see if the stitch holds up to the stretch, no popped stitches is what you are hoping for. That assures that your stitches will hold up.
I agree with Jen on pulling or easing your fabric as you go. Especially if you are sewing a knit bias neckline to a shirt. By stretching the bias tape slightly it retains the curve of the neckline.
Also the coolest thing is using a double needle for hems. Most machines can handle a double needle and it makes such a nice clean double stitch on the front and an incased stitch (almost like a zig zag) on the back.
I think if you practice a little you'll feel comfortable with it. It's actually really fun and opens up another sewing door!
Correction it's not a slightly longer stitch it's a very slight zig zag! My old brain works intermittently!
How knits are to work with varies a lot depending on the knit. Some are sturdy and really easy to work with, others are slippery or wriggly and can be a pain in the butt. Doubleknit with a bit of lycra is my favourite in terms of workability, but it doesn't necessarily have the softest drape.
My regular machine has dedicated stretch-stitches and sews knits quite well, sometimes better than my (rather eldrly and temperamental) overlocker. Stretching as you go is often a good idea but it can distort the seam-lines. Often these will go back after a wash, but not always. If you have a stretch stitch option I'd go with that. You will probably want to stabilize shoulder-seams and maybe the back of neck (look inside a RTW T-shirt and you will see bands sewn along the shoulder-seam and often going straight around the back of the neck.)
I am working on my first knit dress right now. I had been putting off sewing with knits for a really long time because I had heard they were really hard to work with. So I was pleasantly surprised when I started making my dress and the fabric didn't give me any problems. I don't have an overlocker and have just been using the same needle and stitch as I normally would, except for the waist where I used a knit zig zag, and that has worked out perfectly fine for me. One thing I'd recommend doing is roughly hand basting the seam before you sew it on the machine
I sew a lot of knits without an overlocker, so it's definitely not necessary. A couple of tips to add to the discussion:
It can sometimes be difficult to avoid "lettuce" edge on your seams (this is where you get some rippling). I've found that every machine has a different trick to avoid this, but this is the successful recipe I've found.
1) don't skimp on seam allowances. Using 5/8" or 1" seam allowance and then trimming them helps a lot.
2) use a wash-away stabilizer for seams that tend to bag out (necklines in particular). Something like this: http://www.amazon.com/Dritz-Quilting-Washaway-Wonder-Tape/dp/B001UA...
3) I use a normal zigzag stitch (maybe 1/8" wide and 1/10" stitch length) for most seams. When hemming I use a 3-step zigzag set at the widest stitch width (~1/4").
4) With the exception of hems, I usually stitch each seam twice, for added strength. If I don't do this, I sometimes have to go back and restitch some of the areas later (no biggie!).