If that Craftsmen all is one is the same thing as a Dremel, use Dremel's 1" diamond wheel. It'd work even better on their flexible extension. It's what I use any time I have to cut a small grout joint:

We are currently at the point of putting up durock in our new shower. We will be painting redgard on top of the durock. We are using a Kohler cast iron pan and have built in a bench at the far end. We are DIYing it and neither of us have done a bathroom before so we are trying to do all our due diligence so our bathroom doesn't look like crap in the end! I have a bunch of questions I'm hoping some of you would be willing to help with. First, let me explain our design choices so you have an idea of the look we're going for. We're doing a white subway tile in the shower (Interceramic cheap stuff from Lowes). We bought the 2x6 bull nose pieces to run around the sides in the opposite direction as the subway tile. Chrome thermostatic rain shower. Frameless glass shower doors. The floor will be marble with a basketweave tile rug in the center. The vanity is white with carrera marble top. So here goes my questions: 1. Durock, fuzzy or smooth out? I've read that the fuzzy side should go out when using thinset, however I'm unclear on whether or not we should use the fuzzy side considering a layer of redgard will be painted over prior to tile. 2. Niches. We are adding two niches. One larger one, probably around a foot tall, and one narrow one directly below it for razors, etc. The back will be basketweave marble, the sides will be white subway tile we're using on the rest of the shower. We've read floor elfs tutorial on building a niche (THANK YOU) so I think we understand the construction. My question is for the "shelf" part. I'd really like to use a solid base however our budget is busted for getting something fabricated. Would it be possible to use a 3/8" marble tile and somehow polish the outer edge so its not raw ourselves? Which leads to my next question. 3. The bench. We have a bench we've constructed out of 2x4's and plywood. Again, I would really love to have a solid surface instead of tile but having something fabricated is not in our budget. I was considering using 2 18x18 marble tiles which should fit perfectly but would this look strange? Also, same problem of needing to polish the raw edge of the tile. Also, is marble just bad news for a top in the shower which will probably be coming in contact with shampoo, soap, shaving cream etc? I'm concerned about etching and looking like garbage. Any other suggestions on material we could use that'd be in keeping with the rest of our "look"? 4. Grout. I've discovered that I really love the look of white grout with white subway tile. However, I can't stand devoting a lot of time to keeping the shower clean. And I really can't stand dirty grout but I also hate to scrub it. We have a hand shower so we can do a quick rinse after showing to get rid of soap, shampoo residue but the odds of us wiping the entire shower down after each use are slim. Will a white epoxy grout on the walls just be a huge hassle with keeping it clean? Is it worth the premium vs just sealing a regular grout? And, lastly, any direction to a good tile tutorial would be appreciated. We want to make sure we don't have funky looking cuts or awkward looking tiles. If you've made it this far, thank you!! This endeavor has turned out to be a ton more work and research than I expected and this site has been an invaluable resource!

Our shower is about 15 years old and over the past few months, I noticed that the existing grout was getting very discolored and there was some cracks and spots where the grout was chipped. I decided it was time to re-grout the tile. I have removed the top layers of grout (probably about 1/8" to 1/4"). It has been about 7 days, but there are spots that are still damp (I have used baking soda to test to see if it was dry). I have had fans running in the shower constantly since the day I removed the grout. Is there anything I can do to help it dry faster? And is there a way to tell for sure that the existing grout is completely dry and ready for me to add the new grout? Thanks for your help

Thank you so much! I have had the window open and closed (open when warm and closed when it has been raining) since Friday. I hope I have not harmed anything by doing that. I closed the window, have the AC on, the exhaust fan running (which it has been the majority of the time), and I put a fan right outside the shower!