Joe; Actually, once, a LOOOOOOOOOOOOOONG time ago, I tried a golf tee, for a popper, because like I think YOU'RE thinking....... "the cupped top is a great looking popper shape"!?
Well, the SINK LIKE A ROCK, tied to a WEIGHT! haha!! (IF, that is, you're talking WOODEN golf tees!?
Good, high density foam, makes great popper bodies. Go to a garage sale, (or the closet of a small child, relative) and get a pair of foam "flip flops", the thicker ones, (two to thee laminated layers of foam work best), all the better and make your popper bodies out of them. At a garage sale, (usually) a used pair of kid's foam sandals are about 25 to 50 cents tops and have enough material in ONE to make 24 or more, good poppers!
Take a length of galvanized pipe, or, copper tubing, the size of the popper you wish to make and file or grind down the outer edge to make yourself a "popper punch". Merely, pound it through the foam sandal.
Make to shape, with sandpaper, a Dremel tool, or a razor blade.
Saint Paul-"The Highly Confused"
You cannot do a kindness too soon, for you never know how soon it will be too late.
-- Ralph Waldo Emerson