Often I decide at 4 in the morning that I am making a dress or a shirt. And so, I usually buy my notions in bulk. But last night, I discovered that I didn't have any light-weight interfacing. I have a roll of medium-wt but I thought my fabric too light for medium interfacing. What to do?
Interfacing is used to provide shaping, reinforcement and support. Collars, cuffs, facings and plackets are the most commonly interfaced areas. Without interfacing, buttonholes might rip without the interfacing to strengthen them, facings collars and cuffs would be limp and floppy without interfacing and many creative projects would never happen.
Well... before the iron-on interfacing existed, people just used cloth. Use a piece of fabric with enough body for the project, which may be any cotton scrap or for thicker things some felt or blanket. Cotton will do the job. For the thicker interfacing, and in the name of complete disclosure, I've been out of heavy interfacing before and used the fusible ultra firm Pellon and ironed two pieces together. It will work, but make sure it's as stiff as it's called for or you'll not get the same effect in your project.
You can always substitute some other fabric for interfacing. Muslin works good -- I've done canvas when I needed stiff interfacing. I've even just doubled up the regular fabric on occasion!
Typical interfacing comes in assorted weights. You normally either get fusible (or iron on) interfacing or non-fusible (sew in) interfacing. I used to steer clear of sewn-in interfacing because I thought it wasn't as professional looking. After a while, I realized that I was going to sew (and trim) that part of the garment in anyway.
Basting is usually a temporary stitching, meant to be removed. In the case of sewing in interfacing, you're not going to remove the basting. You just need to baste to temporarily tack the interfacing in the correct position. Later on, you;ll sew (with normal stitching length) that interfaced piece to the rest of your project. The normal stitching will pass through the normal fabric as well as the interfacing -- so you'll permanently sew both at the same time.
You don't have to baste -- you could just use normal stitching. It's just that since you'll use normal stitching lengths anyway later on on that piece, you'd basically be sewing it twice.
As to whether or not quilters grid will work, it all depends on the project you're putting together. (Quilter's grid is a thin white fusible fabric that quilters use to help match up pieces for their quilts. It comes with a grid printed on it for ease of use.) Quilter's Grid is about the same weight as light-weight interfacing. It can be too bulky for the end result. If not -- and if you think it will be the correct weight, then it should work fine.
One last caution if you're using fabric as interfacing -- be sure you pre-wash all pieces well to get any shrinkage out of the equation. You don't want your interfacing shrinking at a different rate than the surrounding fabric! Actually all interfacing should be pre-shrunk. Here is my post on pre-shrinking interfacing. Be sure to do this because if, after you've ironed it onto the pattern piece and completed the garment, it shrinks you'll have a very puckered and unappealing garment.
Now, if the fabric you're making the item out of is really heavy like denim you probably wouldn't have to have an interfacing. But if it's light weight material you really should use it to have more body to the fabric.
I did a quick Google search and found a blog post from Slip Stitches and More that recommends dryer sheets as an alternative to light-weight interfacing! (I love how creative some people can be!) I will be picking up the paper-towel roll of dryer sheets next time I am at Walmart! Oh, and I think you should still pre-shrink these sheets too (but what a fabulous and low-cost way to interface your light -weight fabrics)! I'll let you know how they hold up over the next few weeks....