I make my own starch. It's cheap and even if it flakes a bit it doesn't
bother me as I wash my quilts when I'm done. Might not use it on a
wall-hanging.
In a large bowl or pot, stir 1/2 cup cornstarch into 1 cup of cold water.
Stir in boiling water (2 quarts for heavy solution; 4 quarts for medium and
6 quarts for light solution).
If you only need a small amount then half or quarter above quantities.
Sometimes I add a bit more water for the heavy solution as it gets
a bit too thick. You can try and adjust as you wish.
When the cornstarch solution is cool, I use a paintbrush to apply it on
my fabric. Let is soak for at least 30 mins. If I don't have time to iron
I just put everything in a ziploc and put it in the fridge for the next day.
If it's too wet I roll the fabric in a towel first and iron on the wrong side
with a cloth on top so that the starch doesn't stick to my iron. When
the heat has absorbed most of the humidity then I continue to iron
without the cloth. Hope this helps.