I think if I was going to do it again, or any aluminum for that matter, I might bolt down a 13x9 aluminum cake pan on my waste board, then fasten my stock inside the pan. That way the sides of the pan should contain the chip spray along with the WD-40 spray. For the profile cut, i sucked out the chips and re-lubricated on every 2nd pass. And the push button on my WD-40 is touchy - it's hard not to douse the work area. It was very messy. Also, it's hard to dial in the etching bit "zero z" to make a perfect etch. There is a very, very small etching sweet spot for aluminum. I might start etching above the surface and do multiple passes in .001 increments until it makes contact and provides a good result. OR try to find a metal-capable V bit, which would be super cool, but I am not sure if they exist. Anyone?