I use an electrified hot craft/exacto knife by Creative Marks/Walnut Hollow--works like a charm.
http://www.joann.com/joann/catalog.jsp?CATID=cat3266&PRODID=prd53380&source=search
Rae
That hot knife looks great! Just this past weekend I was trying to cut round shapes from foamcore and that was kind of a pain....so I think I need to put the hot knife on my shopping list!
Anyway, what I have done with foam core so far is to just gently score the foamcore on the first cut. You are not trying to go all the way through to the bottom at first. Then, after you've made the first cut, go back over where you cut and finish cutting all the way through. You want to make sure your exacto knife stays at a 90 deg angle so the edges will be straight. Also, you shouldn't have to force it too much. If it's not working well, than you probably need a new blade.
Courtney
Sorry......I meant tearing the foil when you cover the board after cutting!
Your knife gets through 1/2 inch ok?????
I press the cut edges on the table to sort of dull the cardboard edges. And yes, my exacto knife cuts through the 1/2" foam core just ok.
You can also ask the framing department at Michaels to cut it for you as well. They have special tools for this that can cut squares, rectangles, circles and ovals...possible others depending on their equipment. I use to work in a frame shop so have cut many...and the cut is nice and clean.
i have a little tip... if your are looking for cheaper foamcore, the BEST place i have found to get some is the college's bookstore in my area. if you have a college (maybe a university?) near you, take a look! i can get it there for a 1/4 what i would pay at michael's. 
Ok...what size is the foamcore board...I guess maybe depth of it. And will it hold cake tiers well? I am doing a 5 tier stacked wedding cake and I have the stress free supports to use between the layers. I hate to have to cut the boards and never know if they will stand up to the weight...
I use different thicknesses depending on the size of the cake, (for smaller cakes, I use the 1/4"). And yes, you can dowel. It is foam sandwiched between sturdy cardboard. If you're looking to do a long center dowel thru all cake tiers, I would sharpen one end to drive it thru easier.
I followed another cc'rs advice and bought a Black and Decker electric 6V scissor. It's cordless and rechargeable. Holy cow this thing cuts things like butter!
I no longer struggle with an exacto knife.
I bought it at Lowes for $19.99.
Sounds like a great idea. Thanks!
Ok...what size is the foamcore board...I guess maybe depth of it. And will it hold cake tiers well? I am doing a 5 tier stacked wedding cake and I have the stress free supports to use between the layers. I hate to have to cut the boards and never know if they will stand up to the weight...
You may need something sturdier than foam core for your 5-tier wedding cake to be on the safe side. HTH.
Colette told us in her class that all she uses is foam boards. I think the way you have it layed out will work great!
Quote by @%username% on %date%
%body%