Sewing Questions about elastic and stretch fabrics

1) The stretch for individual knits may vary, but yes, you could ue it for cuffs. It would work best with another knit fabric or fabric with similar stretch if that's what you'd like to do with it. If your other fabric doesn't have the stretch that the knit does, then your cuffs won't really stretch at that seam.
2) Yes you can use a zigzag stitch to sew elastic to a garment without a casing. Cut your elastic the the length you need it to be (such as the circumference of the dolls arm for a sleeve) then as you sew it to the piece, stretch it to extend the length of that point- so for a cuff, stretch it the width of the sleeve as you sew.
3) If you're sewing an elastic casing, assuming your fabric is woven, you would just fold your fabric over enough to leave space for the elastic to pas through and sew close to the raw of finished edge leaving an opening to feed the elastic through. depending on what you're sewing, you shouldn't need to do any gathering, since the elastic would do that once it's fed through and secured.

 

But it still might not stretch enough for a collar to allow a head through - you might need to have an opening for that regasrdless - or it might stretch enough ut not spring back to it's original size leaving you with a loose/saggy ribbing collar.

Teddy

 

As an addition to this... I would suggest going with a boat neck design or a scoop etc. to allow for a head to fit through the opening. If you use this as a design element, plus what was mentioned previously, I believe you'll have more luck avoiding the use of snaps etc. depending on the head size. Or, I would just remove the head prior to putting on clothes if possible.

 

In adition to the great advice you've allready got, remeber that all fabrics behave a little bit differently.
You can make tests on scraps before comitting to any elaborate project to make sure there are no nasty surprises.

Mark a scrap with a known distance and stretch it out as far as it goes. Measure again to know by how much the fabric stretches. Release the tension and measure again, did the fabric spring all the way back?
This will inform you on how wide you need to cut a cuff piece to fit it stretched into an unstretched piece and how much you can expect it to pull on the garment. It will also inform you on how much negative ease you need in the pattern to make the finished garmetn fit right.

This is a good time to test the seams and setting on you sewing machine as well. Most ordinary houshold machines can sew stretch, but there may be limitations and workarounds that you need to figure out to get the best resault.

After a while you will work up a feel for this. As is so often the case practice makes perfect.

 

Everyone has given you great advice. Another thing you need to know is that there are specific sewing machine needles for sewing knits and stretch fabrics. They have ball points and slide between the knit threads instead of splitting them.
Definitely get some of those.

 

stretch/knit fabric would work best for this vs woven. You could use woven for coats and things though.

 

One more thing: stretchy knits made with Spandex/elastane are tough to work with on a sewing machine UNLESS you use a stretch needle and an even-feed foot (also known as a walking foot). Go slowly.

 

Experiences vary from fabric to fabric and machine to machine - I used to make a lot of lycra and stretch-satin cycle suits and bodysuits (it was the early 90's, and I was built like a skeleton. Don't judge me!), and just used my machine's ordinary zigzag foot without any issues. I rarely encountered a fabric that I had to switch to the walking foot for.

Teddy