I thought I'd give an update with the prep of 1,100 sf in my basement. I'll add a little more info and pics of the whole process so far in this post. It had 12"x12" vinyl tiles that were coming up after we had an overflow in the basement. House was built in 1955 and tiles were set with black hard tar type glue.
I used the
HD Coating Removal Tool, probably about 20 hours of this. I used water in a sprayer to get things started. The first room I used a lot of water and it was like smearing doggie doo everywhere. Here's a pic after a lot of cleanup. I had to hose out the shop vac it was so bad. The hose only had about a 3/4" hole down the middle of it, the rest was gunked up.
After that, just wet, not soaking to start and a quick spritz before the next pass and no water on the final pass, and that worked really well. The black gunk would 'booger up' and about 3 passes would get to fairly clean. Successive shots showing the 'boogering' with less water to start and then dry getting to dust.
So I rented the
HD Concrete Prep Tool to clean up some of the scunge still left, maybe 12 hours with this tool. This worked sort of so-so. While it did take off another level and smoothed some of the previous tools swirl marks it still left a lot of discreet gunky areas:
And the edges and corners were still to be done. This took about 20 hours of fairly intense work (4 rooms, 3 closets, hall, powder room).
Here's is the winning formula for edges, corners, and spots the other two grinders weren't able to get: I used a 4.5" Milwaukee
angle grinder,
dust shroud, adapter hose to shop vac,
Dust Deputy, and a DEWALT DW4774
diamond cup grinding wheel.
I'd venture that the brand of the grinder, dust shroud, and diamond cup grinding wheel aren't all that important. I got the Milwaukee brand shroud and it's the same thing as the pic above, just black plastic instead. The diamond cup wheels are $30-80 and most places sell them. These wheels are pretty awesome and I think everyone should own one! Only negligible wear on the wheel even after all this work. Make sure your grinder has a spot to put the handle on the 'top', i.e. vertical when grinding the floor. It makes life much easier to keep the wheel flat on the floor.
Here's an example of edging where I started, the edging is right up to the sheetrock. The gouges can be seen, the diamond cup wheel is pretty aggressive and it is important to keep it flat on the floor! After this I got better with it. It is really tiring to use, but the payoff is worth it.
So the shroud - 99% of the dust is captured, it works! Use this even if you are in a 'dirty' area just so you can see. The way the shroud part that is removable for edging works on the the grinder means that corners are left with a bit of unground area. After I had done everything else I put the stock Milwaukee shroud on with the diamond cup wheel so I could get the corners and around door jambs a bit better. This worked well, but just 2-3 seconds and there was a giant dust plume. I even had the shop vac running with the hose just a couple of inches away. Didn't matter. Really showed how well the dust shroud worked.
Props to the Dust Deputy as well, it was capturing about 75% of the fine concrete dust before it got to the shop vac.
In hindsight, I think a better order would have been:
1. Coating Removal Tool
2. Edging, corners, and larger swatches in field with angle grinder
3. Concrete Prep Tool
4. Use angle grinder to clean up any areas in the field.
This would allow the Concrete Prep Tool to work down most of the angle grinder marks.
And one last note - I had a 4.5" grinder so that's what I used. I would have been tempted to go 7" if I would have had to buy one. But I'm glad I had the 4.5" one, it was able to get in a lot of tight areas a larger one would have had trouble with (behind the toilet flange and under the toilet water supply, for example). If you only have a larger area with no obstructions a 7" grinder would work great.
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