October 2013 updates on Diamabrush method
You can rent these machines, or something similar.
Your 175 machine and the $40 rental diamabrush from Home Depot and some sand will do it.
Or chemically with Bean-e-doo.
Hi! I am new here and my husband and I are DIY types. I learned about diamabrush and so much other useful info from this board, so I wanted to share some info that might be helpful to others.
First - Home Depot no longer rents the Diamabrush. They still have the videos on their website but the rental center manager told us that people were bringing them back trashed after only one use so they weren't able to make any money on them because they had to keep replacing those expensive blades each time. However, you can buy the larger sizes from UnoClean. Great customer service and reasonable prices and free shipping. So that's what we did and the 5-blade, 16 inch brush was $290. Be sure you order the clutch plate or it will be useless. That $290 was including the clutch plate.
Second - the HD people don't always know which floor maintainer to give you. It is the Clarke American FM1700.
Third - you can buy the smaller (4.5 and 7 inch) Diamabrush at HD for the edges and corners, and you can rent or buy an angle grinder.
Fourth and probably most critical - WATCH THE DIAMABRUSH VIDEO. IT IS MUCH BETTER THAN THE HD VIDEO, WHICH DOESN'T EVEN MENTION WATER. THE DIAMABRUSH VIDEO SAYS YOU MUST USE WATER AND BOY ARE THEY RIGHT. At first we tried a light misting. Then more and more water - the problem being that it can get slippery - not good when you are trying to control a heavy machine. So be super-careful. But water was the key to the operation!
And that brings me to the last point - do NOT assume you need multiple passes. We had 1,000 sf in three rooms and based on what we read here and elsewhere, we were thinking 7-8 passes. That would have taken days! So in the first room, we did three passes and it looked like there was still mastic on the floor. Well, there was. We were getting discouraged. But it turns out it was just ground-up mastic that we were just spreading around! I'd been wet-vacuuming the slurry and when an area became too dry, I used the sprayer to re-wet an area. As I sprayed, it became obvious that there was clean concrete under the slurry. We took a mop and a nice, big squeegee and cleaned up the slurry and sure enough - we were done. Yes, there were a few small patches remaining but repeated passes didn't remove them - there must be small dips in the concrete. We'll hit them with the hand tool but I can't imagine that the shot-blasting won't get most of that off anyway.
So the next day, in the larger room, we did one pass and then washed and sure enough - one pass was sufficient. Same result - a few patches (that again, remained after a couple of repeated efforts) and otherwise, bare concrete.
So finally - a helpful hint - this is a two-person job. You really want to get that slurry cleaned off as quickly as you can. Concrete is porous and the water will carry the water-slurry mix down into the concrete. It probably dries fairly quickly but the whole point of this exercise was to get the concrete ready for (in our case) sheet vinyl so the last thing we want is MORE moisture. We have a week before we shot-blast and another week before we apply the epoxy but still, we sure don't want to be saturating the concrete with water. And by the second day, we were hitting that concrete floor with a garden hose so we kept at it with the squeegee and the wet-vac so we wouldn't have any water standing on the concrete.
Also - do the clean-up with a hose, not buckets. There is SO MUCH slurry that you end up emptying and refilling the buckets constantly. By the time you get back to the spot you were cleaning, the slurry has started to get absorbed by the concrete and you end up cleaning the same spot over and over. Not to mention the huge amount of time in emptying and refilling buckets or sprayers.
I hope this info helps other DIYers.