Just as an introduction, this was NOT a difficult project, nor was it one of my favorites or most functional, but I needed something small to make as an 'Acrylic Blocking Sample/Tutorial', so, here goes.
I've had a lot of people tell me that blocking acrylic blend yarns is not possible. I wanted to add a tutorial here to show it is not only possible, but necessary. If you do not block your acrylic projects, they will look like my pre-blocked bonnet: A ball of mush.
To block your acrylic, the best method is to use steam. It will not kill your fiber, like directly ironing it, it blocks more dramatically than trying to wet block (which usually has no result), and is PERMANENT! YAY!
First off, pin your acrylic item down in the shape you would like it to ultimately be. Because this item was small I pinned it directly to the ironing board. For larger items, cloth covered blocking boards can be used, with either an iron to block or a steamer, if you are lucky enough to have one.
Next, hover your iron on a steam setting 1-2" above your work, allowing the steam to penetrate the piece. If you hold the iron directly on the yarn, it will cause the plastic (AKA acrylic) in the yarn to melt and flatten, looking strange, possibly ruining the project/yarn, and possibly melting and adhering to your board/iron. No bueno. Hover, hover,hover.
After the steaming is complete, let the item cool, take out the pins, and if it is flat enough for your liking, it is complete.