I need to make some rice krispy treats for a structural support. Is there a trick to getting the rice krispies harder?[/b]

i usually just mush them together. I've never used them for structural support though. Don't know what you're doing, but can you mold them around a dowel?
One tip is don't use margarine, i did once and it was completely different than what i get when i use butter. (was trying to save money since they wouldn't be eaten.) hope this helps.

I use candy melts instead of marshmallows. Sets up hard enough to carve.

Candy melts!

We can't use dowels - it's a competition and everything has to be edible.