Previously I have stated that I don't make many muslins ( a test garment prior to sewing with the real garment fabric) but in the past couple of years I have sewn them more and more. Trying out new to me pattern companies, sewing for others, doing pattern testing for an indie pattern designer - these are all reasons I've had to sew up a muslin.
So I wrote a post for Craftsy on my top reasons to sew a muslin. In fact I was surprised by how many reasons I actually came up with. And all quite valid in various circumstances. Here is the link to the post which you can read there.
Yesterday I had a 60% off coupon for Joann Fabrics so I went over there early and bought a few yards of the 120" wide muslin fabric for about $ 8. I try not to buy much actual muslin fabric but that is kind of a steal, and using the traditional unbleached muslin is really nice for fitting etc. I can mark all over it with a pen while fitting and see the markings easily so as to be able to transfer back to my paper pattern pieces. Also the unbleached muslin takes the markings from the waxed tracing paper very well. A while ago I bought a package of the red wax tracing paper and so I use that now to mark darts, seamlines etc. The red shows up really well on the muslin fabric. Sometimes I even go over the markings with pen/pencil because I really like to see all the dots and other markings when I am doing a muslin.
As for other options on muslin fabric - the example above left in blue is an old bedsheet. (for my black wool coat, Simplicity 2311, on the right is the muslin for my version of the House of Pinheiro Brasilia dress). While old and worn bedsheets might seem like a good choice for muslining garments I find them a bit troublesome. For one thing no selvage - so you have to figure out the grain on your own. Secondly most sheets are quite tightly woven and very difficult to pin. But in a pinch they will do. So I do prefer actual cotton muslin fabric - and I save all kinds of scraps when cutting out muslins - then on the next project for collars, or other small pieces I use any scraps first and then cut out the larger pieces. My miserly tendencies know no bounds!
Another way to "find" fabric for muslins is to use quilting cottons and use the back side (without the printing) as the outer side of the test garment. If you are using quilting cotton the print can be a distraction when fitting but by flipping it over and sewing with the pattern on the inside you can get a less distracting version for your fit evaluation. I have bought a lot of muslin fabric at garage sales. Don't overlook some of the horrible stuff - particularly poly double knits which nobody has willingly sewn with since ? but is a really nice stand-in for a modern ponte knit when pattern testing.
Thanks for the comments and emails on my idea about sewing instruction/consultation via Skype. I am working out my ideas and will be back soon with more details.
Happy vernal equinox sewing,