More grinding concrete

Today was our best day of griding yet, which does not mean that it was a good day. Grinding is a lousy job. But what made today better is that we got through the 50 grit grinding pad, which means we are done shaping, leveling and removing material. From now on out, we use successively finer grits to smooth and polish the surface. We'll go through 50, 100, 200, 400, 800 and 1500 in the process. Generally, grinding is considered to be using pads up to 800 grit, and over that is polishing. The glass-like finish of granite is obtained using grits of 3,000 or higher and special buffing compounds. It isn't good to go over 1,500 for concrete because the sealer will not adhere well.

Another thing that was good about today's grinding session is that the tarping was much better. There were no major leaks, and I was able to leave the tarping in place, which saves about 2 hours per work session. It's also much better for the floor. We also discovered we can use a lot less water. The water serves two purposes - it catches the dust so we don't breath it and it keeps the grinder and the countertop cool so there are no burn marks. Instead of having lots of water spraying everywhere with just a little dust in it, we use less water and let it get sludgy before removing it. So there is a lot less water and it sprays less - it is the texture of mud.

We finally finished around 2:30 a.m. Not fun!