At my local Owl Hardwood store they have a section for Catalpa wood with a sign up that says "New". It's very light weight and has a nice grain to it. It's about as soft as pine but much lighter in weight.

I started a two and a half hour carve that was only .2" in depth and it started out very smooth and seem to cut like butter. But by the end of the two and half hours the flex shaft was very hot and the bit was making a lot of chopping noises. I twirled the bit in my fingers and the tip didn't seem to have the same bite that it used to have. The bit only had about 80 hours of carve time on it and I was expecting to get up to 250 hours at most. While the wood is very soft somehow I think the molecular structure somehow effects the carbide.

I'm kind of afraid to try carving some more of it. I only have a little bit left but I think I'll try another bit on it using my other CNC.