My local welding supply carries various cutting discs/grinding wheels, etc. They make one with the depressed center for the 4-1/2 grinder that is .045 thick, for minimal heat build/material loss. I prefer to use the more expensive discs made for stainless, they tend to put much less brown haze in the air and all over your shop than the cheapy flea market cut off wheels, and last quite a bit longer as a trade off to the increased price. Yes, more money up front, but longer use, less changeout, etc. so it balances out in the end. I also use the 3m disposable PAINT respirator for a better face seal, and the exhalation valve under the mask certainly helps to keep your safety glasses from fogging up as with the dust masks.
