First time cutting foam

[myxpykalix]

This was a science class project for one of my granddaughters to make a baking soda volcano. The parts are just stacked, not glued. We will glue, sand, and paint it.

I had not really cut foam before (just practiced on thin stock) but if you look at the bit in the picture the foam must have melted around the bit and hardened. I had to stop the file a couple times and chisel off the hardened foam.

Clearly i need advice on feed/speeds for foam cutting. My router speed was 10,000rrpm speed was about 1.66ips (?) using a 1/2" ballnose bit. What is the optimal settings? This was pink HD foam...:cool:

[knight_toolworks]

crank up the feed speeds as fast as the machine can go. brady says a four flute works best but so far I don't have one to test.

[erik_f]

Man how do you do it jack! Those Chips Ahoy look so real!

[butch]

Jack
I did some 3d cutout/carvings for DU, in 'blue foam'(same as pink) to use at the kids table for rubberband gun targets. I cut at 10k and 5ip, and it did very well. I used a 2 flute 1/4" ballnose from Centerion.
I then 'painted' Westcoast epoxy on them to give them a hard surface. I understand they are keeping them for next year and someone is painting them.