I’ve seen the “foamies” in two sizes at the local Michael’s craft store. I have both but haven’t done anything useful with them yet…thought of poppers the instant I saw them. 
You can get all the foam cylinders you need from Stone River Outfitters, http://www.stoneriveroutfitters.com/cgi-bin/shopper.cgi?key=SYN_M0632&preadd=action. It comes in many sizes and several colors. I use them to tie Richard Komars Bullfrog.
Im sure everyone is well meaning when they answer post on FAOL,but when one asks for a type of material they really dont need some answers.
Netcraft www.jannsnetcraft/com has foam popper body material,white color that can be colored with permenent marker,acrilic paints,or reflector tape. Sizes from 1/4 thru 3/4 dia in 1 1/4 lengths. The 1/2 inch you asked for comes 6 to a pack. They also have cork,formed foam popper.BILL :tieone:
Everyone go back to Dianes earlier answer if you really want the best information about using foam for flies Jim Hatch is the expert–I have some of his Dremel flies and they are the best I have ever seen.
Huh? Did we do something wrong?
He asked for foam cylinders he could cut to length. Not precut popper bodies. What I use comes in long cylinders, and you cut it to your desired length, like Rainys Float Foam.
If my answer was inappropriate, my apologies…
Like Gigmaster, I’m not sure where you’re going with either Mr. F. Isn’t the purpose of asking a group of people something? To get a variety of answers? If you’re referring to the answers pertaining to making your own cylinders -vs- purchasing, to most of fly tyers, making your own for a fraction of the price of fly-shop-bought-packaged-products is a PREFERRED source for materials.
Sorry if some didnt like my answer. You will find many strange answers to some post. Yes—He asked for 1/2 dia in lengths so that he could cut to size and there were answers to that request. Foam sheets flip flops softies etc BILL :-P:-P:tieone:
Not that it was not liked, just wanted to know what point you were trying to make. That’s all, nothing more, nothing less. Many threads do indeed get way off topic, but this one is only guilty of replies offering alternative sources.
That way I look at, If someone is only looking for a place to buy a specific item, Google, Bing or any other on-line search engine is much more efficient. Just my ever so humble opinion.