New to the form and have a question about masking a Vcarving. I'm using a brand new Bosch 90 degree carbide tipped Vbit cutting letters and numbers in MDF. The MDF was sealed and painted with 2 coats of latex before carving. The masking material I'm using is OraMask 813 fro signwarehouse.com and was applied very firmly by burnishing with a scrap of MDF leaving no bubbles.

The problem I'm having is the bit doesn't always cut the masking material cleanly leaving bits and fuzzies in certain places. It seems to always be where the bit exits the material. Most of the larger letters (1.5") cut pretty cleanly, but the smaller ones (.75") tend to have more of the exit remnants.

I've tried 10k rpm up to about 20k rpm with not much difference. I'm currently cutting at 100 inches per minute and haven't had a chance to vary that yet. So my question for those with experience is what would be the best combination of tool and feed speeds with this masking material to get clean cuts? Is there a better masking material I should consider? I've read about Dr. Crumley's Snake Oil Mask which sounds great for rougher materials, but I've also read that the OraMask is good for smooth surfaces.

Any suggestions would be greatly appreciated. Many thanks!