You can buy the water brush just about anywhere, HobbyLobby, Michaels, Art supply stores, online, Target, Blicks and JoAnn's. According to a blog, a guy purchased 4 for 5 dollars in the kids art section at Target. They come in a pointed end or a large blunt end. They are used for watercoloring, scrapbooking, but mainly water coloring. Or... you can do what Sharon Shamber and her daughter, Cristi Fincher do, spray some starch in a cup, and dip a stencil brush in and "paint" around the freezer paper, fold and iron. Cristi has a Craftsy class for paperless paperpiecing....you do use the paper templates, but you don't sew through the paper,. it is a method of starching with the stencil/starch brush and ironing over the freezer paper pieces, then using Elmer's glue to "piece" the block together, then you sew on the seams....sounds strange, but it seems to work. Just started watching yesterday. I digress, JoAnn's has the brushes on sale today. There is a set of three different tipped in a pack for $17.99....but you maybe able to use a 40% coupon online for less. The others are Pentel, Koi, Sukura......lots of choices if you don't want to use a stencil brush and starch in a cup.