Your link took me to the home page for Joann.com, but I think I found the thing you were talking about - a blue wedge-shaped thingy?? Very interesting. I may be tempted to try plastic snaps.

I have a very old Dritz snap fastener that looks like a plastic plumbers wrench. It's sort of a hand-held snap press, and it works great but doesn't take all sizes. Unfortunately it's no longer made.

Nevermind, the link worked the second time for me!