When you use this tool on foam core, does your finished circle have a smooth edge or is it sort of jagged? I tried using one earlier and my edges weren't smooth. I'm sure it's probably user error but wanted to ask. If you get a smooth, clean, cut could you tell me how you do it? Thanks!

I just bought one myself and had the same issues! Right now I'm thinking it was a waste of money so I'll be interested to see other posts about this!

How thick is your board? I bought that also and have 1/2" board...I had to really push down to cut it...flip the board over and cut it again. It wasn't entirely smooth but I got better results than using an x-acto knife or the heated craft knife I also bought.

I have one also and use it on all of my circles. Like Kellbella, I have to press down while I cut and I cut one side then flip to the other. I normally keep the center point of the circle just over the edge of the counter so that I can press the cutter all the way down. It seems to help make a smoother cut. I hope that makes sense.
Vickey

Why not use a foam core circle cutter? It is made specifically for foam core. I would think you would get a better result. Foam core and drywall are different materials and behave differently.
http://www.foamcoreheaven.com/nefofobocicu.html

I have found when I cut foam core,, if the blades aren't sharp enough (I use an Xacto knife), the edges come out quite jagged.

If you don't want to spend the money to get a new tool since you have this one, you could use a sanding block to smooth the edges. Get one that is super fine. I use a craft one. You might also find one for nails, may e even at the dollar store. (I don't know if the ones at the hardware store would be smooth enough.)

Oh, I forgot to say. When I learned to cut foam core, I was told to remember that you are cutting through three layers, so the best way to cut is in 3steps. The first cut goes through the first layer of paper, the next through the foam and the last through the second layer of paper.

SecretAgentCakeBaker according to the website that you posted, the foamcore cutter will only cut up to 6". That would really limit you on the size of cake circles that you could cut. With the drywall cutter, I can cut as large as 16" I think. But it's a really cool tool.

Oh yeah! That would be a problem, huh?! Sorry I didn't notice that. I'm really, really tired this morning.

I used it on a 3/16" board. I think I'll just do what someone suggested and cut it in 3 steps, then use a nail file or craft sander to smooth the edges. It won't be perfect, but it will be better than the exacto knife I was using. Now that was a mess!

Thanks to everyone who chimed in!

I think the issue with cutting the foam section of the foam core cleanly is a very sharp, angled blade, like those in an xacto knife. We cut foam core often for crafts and making games. When the blade isn't very sharp,that is when I have to use the sanding block. When I use a new blade and cut with the three step method, the sanding is not needed.

What if you make the first cut with your circle cutter, then use the Xacto knife in the grove to cut the foam? That might work a lot better.

What kind of blade does the dry wall cutter use? Is it like a rotary cutter blade, like the kind used for fabric, such as in this circle cutter for fabric?
http://www.olfa.com/CircleCuttersDetail.aspx?C=50&Id=149

Or, does it use an angled blade, like the one used in this heave duty cutter? (unfortunately, this one only goes to 12 inches, plus it's more expensive than the drywall kind)
http://www.olfa.com/CircleCuttersDetail.aspx?C=51&Id=64

Is there a way to put a different kind of blade in the drywall cutter?

It uses a rotary cutter. I don't think you can switch the blades out. It's brand new so I assume the blade is pretty sharp. lol Thanks for all of your help. I'm going to experiment some more this week and hopefully get a smooth edge somehow.

I use one and yes it gives jagged edges but I cover them with ribbon so it's not a problem.

THIS Exacto right here, the small utility knife, not any others and especially not the typical silver ones with long flimsy blades (yes flimsy for this type of use) are the only ones I have success with when cutting the thin foam core. No jagged edges ever, no going back and cutting in steps, and the blade doesn't wobble. My favorite. Now regular Exactos for cutting paper and GP and fondant, sure, those are the best bet. But these are more stable in your hand as you cut.

http://www.xacto.com/products/cutting-solutions/knives/knives/Lightweight-Retractable-Utility-Knife-8.aspx

For 1/2" thick, I use a regular box cutter, and it slices right thru like buttah.