I was recently introduced to Magic Sizing and would never go back to starch. Starch leaves a "snowy" residue which sizing does not. I love working with it

I prefer using the concentrated starch, one, because I pay less than $5 for a gallon versus the spray can and it makes at least 10 times more which is also why I don't use sizing spray, it's too costly for the amount you get. If it came in a concentrated bottle, then I might switch but until then, I'm using starch.

I am new to quilting and so far I have only made 4 or 9 patch blocks and quilted them SID. Why do you use starch at all. What is the purpose

But how can it be true about the yellowing?
My mom starched my dad's work shirts to a faretheewell, and believe me he wore them til they fell apart and they never, NEVER yellowed. And they were white shirts, not blue or any other color. 8-)

Well, I just found some Peppermint Patties that I keep here for my grandson, and all the chocolate had been eaten off them, and nicely unwrapped too. The next day I caught 2 mice on that shelf in my basement. I don't use starch except on my crocheted doilies.

I have always used Magic Sizing, and it works well. It is also inexpensive. About a dollar a can at Wal-Mart. Have never had a yellowing problem.
If you want to spend more $$, Mary Ellen's Best Press is nice. Comes in several scents too. :)

I would have to agree with this. I have tons and tons of doilies in my cedar chest, made by my grandmother. She had a heart condition and had to lie down most of the day. She was never without some kind of handwork, mostly crocheting doilies. I have HUNDREDS of doilies. Someday I'm going to incorporate them into quilts, but for now, there they sit. And they look as good a the day she made them some 70 years ago.

I've never used starch before reading about it here. I read that it helps decrease the amount of stretching or distortion when cutting and the stiffness it creates makes cutting accurately much easier. I tried it on my most recent quilt, a flannel one, and found that it worked very well. It is my most accurate quilt so far (despite many seams to match), and I plan to keep using starch or sizing from here on out. I'm sending the quilt to Illinois, where it is hot and humid and there are plenty of bugs, but I'll wash it first to remove the starch - so it's soft for the baby, and in case the starch would attract any critters.

Be careful though. If you iron while it's still damp, it can create distortion.

I agree, for clothing it is not an issue, but for fabric it can be.
If you distort your fabric initially and then cut and sew, when the fabric is washed and dryed it will go back to it's original form and your quilt can distort.
I spray my fabric and let it dry, then iron to get the wrinkles out. You can use steam if the fabric is stiff, and it shouldn't distort the fabric, unless you get really aggressive with it.