If you haven't already read the post on Supplies and Materials I suggest you do so before you start, but otherwise let's talk about what sweaters to use and where to find them.
Start with your own closet. We all have sweaters that don't get worn because they have little moth holes in them but we can't bring ourselves to throw out. these are perfect as long as they are wool. Ask family and friends to donate their castoffs.
You might consider making what I call a heritage blanket using recognizable sweaters from family members or friends. This blanket was made using several of my fathers sweaters which I find comforting.
Otherwise, start in the men's department of your local resale or Salvation Army store. The sweaters are going to shrink substantially so XXLs are great! Good old crew necks, v-necks and turtlenecks will provide the most material. If you want a blanket of some size then stay clear of sweaters with zippers and other details unless you can incorporate them in to your design.
In Chicago sweaters run between $2.00 and $4.00 each but I usually buy them at half price unless they're huge and a killer color. A little warning here as it is very tempting to buy lots of different colors only to find that they don't work well together; and try to collect sweaters of similar weight so the sewing is easier. I tend to buy solids but, you may prefer to work with stripes or other patterns so don't let my style influence you; I've seen gorgeous blankets made using all sorts of patterns.
Most important of all you want 100% wool. My personal favorites are merino and lambswool as they both felt consistently and are made even softer in the felting process. It is getting harder and harder to find pure wool though as many of the manufacturers are adding nylon and other synthetic fibers and they just don't felt properly so read tags carefully. Having said that, SOME of the blends will prove me wrong and shrink fine, but for the first time stick with pure wool. Check the cleaning instructions as well because some of the wools are washable now and that won't work either. I've had some trouble with the really lightweight merino used in men's collared sweaters and am not sure why, but for the most part these are really good choices.
Try to collect about ten sweaters. This will give you flexibility if something doesn't felt down and you'll still have enough to get started. Lastly on color selection; neutral colors are your friends - gray, oatmeal, taupe, black. I almost always buy them when I see them as they help fill out the design. Remember you are limited by the color selection available. I happen to enjoy this challenge, but I also have a large stock of sweaters.
Timing is somewhat important as many of the resale shops pull their wool sweaters May 1 and don't put them out again until October 1. So, if this becomes a hobby for you buy your sweaters in the next six months so you have stock come next September.
The other challenge is that I always get the sweaters home and find that the burgundy cashmere would look great on my husband or the spring green lambswool cardigan is just what I was looking for - so be prepared to lose a few to your closets. I've got to believe that most of us who do this are scavengers at heart and can't pass up a good deal.
