I have a six by six square cake dummy that I need to cut down to four by four. How do I cut it and get a smooth edge without the huge mess and bumpiness?

With a hot wire. Crafts stores sell these electric tools that are made for cutting foam... normally for less than $15-$20. HTH.

CWR41 Thanks for the help but is there anything that I can use that I dont have to go out to buy? I live out in the country and need to cover this teir.

Anything else is going to be a huge mess. If you can't heat your own wire, maybe you can heat your knife blade with each cut. The goal isn't to saw it, but rather let the blade melt through it slowly.

CWR41 thanks for the help I think I will try to heat a knife