I rented the Home Depot diamond grinder last night. It consists of the Diamabrush concrete prep tool plus and a floor scrubber with vacuum attachment. I spent 5 hours on 850 sq ft of garage and picked up about a 5 gallon bucket of concrete dust. Maybe I was expecting too much, but it didn't seem to do much more than scratch the concrete. I'd call it more of a smooth finish than 100 grit sandpaper. Things like rust stains (from the snowblower) took considerable time to remove and after I hosed it off you can still see rust marks. This morning the concrete looks dull and scratched. I think it probably did what it needed to do, but was much much slower than I anticipated.
Not impressed with Home Depot diamond grinder
- Thread starter gobble
- Start date
Shea
Well-known member
Actually Gobble, 850 sf. in 5 hours for a DIY job is smoking fast. I would pat yourself on the back for that. 
Check out this thread where some guys are taking twice that long using other methods. Based on your description of a dull scratched look, it sounds like the surface is just right.
As far as the rust goes, you have to remember that is settles down into the pores of the concrete. Many times grinding alone will not remove all of it. Try pouring some vinegar or lemon juice on the stains and let it sit awhile without drying out. Scrub with a brush and rinse away. If it's bad rust you may want to use a little muriatic acid or and aftermarket rust remover.
Check out this thread where some guys are taking twice that long using other methods. Based on your description of a dull scratched look, it sounds like the surface is just right. As far as the rust goes, you have to remember that is settles down into the pores of the concrete. Many times grinding alone will not remove all of it. Try pouring some vinegar or lemon juice on the stains and let it sit awhile without drying out. Scrub with a brush and rinse away. If it's bad rust you may want to use a little muriatic acid or and aftermarket rust remover.
Garage Flooring
ALLIANCE MEMBER
Actually Gobble, 850 sf. in 5 hours for a DIY job is smoking fast. I would pat yourself on the back for that.
As far as the rust goes, you have to remember that is settles down into the pores of the concrete. Many times grinding alone will not remove all of it. Try pouring some vinegar or lemon juice on the stains and let it sit awhile without drying out. Scrub with a brush and rinse away. If it's bad rust you may want to use a little muriatic acid or and aftermarket rust remover.
Edgewater Industries makes a rust remover. I have not tried it, but I hear it works well. http://www.pour-n-restore.com/CA-Rust-Remover-Flyer.pdf
SapesOfIndia
Well-known member
I tried 1:4 diluted Phosphoric acid from Home Depot and it was able to remove rust stains.
LegacyIndustrial
ALLIANCE MEMBER
Ditto Shea's response.
You did it right.
You did it right.