Removing previous Rustoleum from concrete

[KGA109]

One year ago I diamond-ground my floor (thoroughly) to prep for the HD Rustoleum water-based epoxy. Something went wrong and a year later I have hot-tire-pickup in a few spots.

Time for a new, better coating.

Yesterday I ran to HD to grab a floor machine and their 10-blade, 25-grit diamabrush.

I spent ALL DAY working to get the Rustoluem removed. I have probably 30% removed, but the rest is scuffed down smooth. The areas closest to the doors did come off pretty well, which makes sense (no UV coating was applied).

Questions:

Am I using the correct Diamabrush disk (10-blade, 25-grit)? HD had another one, less aggressive (more blades) but its meant for merely profiling the bare concrete.

I'm assuming where the Rustoleum is very difficult to remove with the floor machine, that would tell me I have good adhesion (more or less). Can I apply my new coating OVER that, as long as it is scuffed down thoroughly with the diamabrush? Like i said, where the was hot-tire-pickup, that DID come off and that is now bare concrete.

I'm about to spend at least the whole morning, again, working to grind the Rustoleum off, but I already spent 7+ hours on it yesterday (800 sq.ft.). It's brutal.

And also - wet or dry? I've tried both and doing it dry is just easier to see where I've been and what I am accomplishing.

 

[shaun oriold1]

I dont know much about that machine, but with my machine I use 25 grit segments to so you're good there. The machine isnt heavy enough, so its just a matter of persistence to get to bare concrete -unless there is a way to add weight? I also think they make a PCD disk you can put on which scrapes the floor. ITs what I use when I need to remove gluey coatings, and the grinding segments just get gummed up.

You can apply over the old coating, but you run the risk of it flaking off with the old floor coating.- thats a decision you have to make.

As for wet / dry. Wet will reduce the dust, and keep the diamonds cooler. But create more of a mess of dirty run off. Dry dust is easier to vac up.

 

[KGA109]

The machine is just a Clarke floor sander.

This morning I grabbed a new 65# bucket of joint compound and put that on top of the machine. It actually balanced perfect and probably doubled the efficiency of the sander.

I worked on it all morning and just recently finished up. there are still spots of the previous coating, but everything is ground down equally and all of the coating is sanded down to at least eliminate the gloss and 100% of the orange-peel texture.

Even with the added weight, I'd be there for probably 2 more full days to get it all down to bare concrete. I believe I have it pretty good, and I'm pretty picky.

I was just surprised how slowly it was cutting the Rustoleum.

 

[tncatadjuster]

Adhered epoxy is tough, that's why I sell it.

 

[James-W]

I have never done an epoxy job so I do not speak with any sort of experience in this. All I know about it is that everything I have ever read about putting down an epoxy floor says that proper floor prep is 90 percent of the process. Without the proper floor prep, you will most likely have problems later on. I am not trying to tell you what to do, but if it were my floor I would take the extra time to get it down to bare concrete again. It's a lot more work and it will require a lot more time, but I think in the long run it is the best way to do it.

 

[navin]

Is this the attachment you are using? http://www.garagejournal.com/forum/showpost.php?p=4225672&postcount=37

 

[KGA109]

Is this the attachment you are using? http://www.garagejournal.com/forum/showpost.php?p=4225672&postcount=37

Yep. The 10 blade, 25g Diamabrush.

I used it both wet and dry. Wet wasn't a revelation like that guy described.

I may keep grinding on it today/tonight yet but I really believe I have a good surface as it is. I have a pretty solid background in automotive painting so I have a good understanding of detail and prep. But after 1.5 straight days grinding it wears on ya.

 

[LegacyIndustrial]

Adhered epoxy is tough, that's why I sell it.

 

[LegacyIndustrial]

Yep. The 10 blade, 25g Diamabrush.

I used it both wet and dry. Wet wasn't a revelation like that guy described.

I may keep grinding on it today/tonight yet but I really believe I have a good surface as it is. I have a pretty solid background in automotive painting so I have a good understanding of detail and prep. But after 1.5 straight days grinding it wears on ya.

If it's down tight then go for it.

 

[navin]

dang... Well that kind of worries me as I have some Epoxy-Coat I want to grind off in my 400sqft garage.

 

[Skidddmark]

To the OP, depending on what you are putting on this time you may want to remove all of the water-based material. What you put down could lift the water-based material...also
-diamond cup wheel on a 7" grinder with a vacuum shroud- grind till you see white concrete but back off when you see aggregate

 

[KGA109]

I want to open this question back up - after grabbing my angle grinder with a double-row diamond cup wheel, I quickly noticed that the original coating that I was trying to remove with the big floor machine, rips right off fairly easily with this diamond cup wheel.

My intention was to use this angle grinder for the corners and edges, then go ahead and paint the floors as-is, trusting that the Diamabrush-work that I did with the floor machine put the proper profile on either the bare concrete that it exposed, or the previous coating that would not come off (and it did, I can clearly see a good scuffed pattern on the concrete and the previous coating of epoxy).

BUT, I could also sit there and grind the entire floor by hand with my angle grinder, which at 775 square feet, I'm guessing would be two full days of work. But it would be THE correct solution.

What do you do? Grind it for the next two days, or trust that the previous coating has a good profile (the patches where it is left, which is probably well over 60% of the floor).

Its easy to say "grind it all down", but I have a lot of work going on, and I do believe that the way it is currently, will work as well. But I'm OCD, and want to cover every detail properly, but also want to be efficient with my time.