Did I grind enough?

[cabinetboss]

Hello Everyone,

Thanks to this forum I"m Doing a 100 percent solids epoxy job in my 750 sq ft garage. I went to HD to rent an Edco grinder and ended up using the Diamond brush removal pad and a polisher to profile the floor and remove what I think is existing sealer. After about 7 hours of grinding I have the results shown in the pictures. It definitely is not super rough like 80 grit sandpaper and there are some darker areas. A few if these spots I grounded on for several minutes to see if I could remove them

I"m contemplating renting the Edco 10 inch and giving it another round of grinding but maybe it is well enough? The guy at HD said the Edco is a bit more agressive, but I read alot of good things about the Diamabrush on here. Any input would be great.

Thanks in advance!

 

[Shea]

Many times the darker spots are from denser concrete and will not turn a lighter color. That is normal. Did you do a water test? If it absorbs drops of water fairly quickly you are good. Just test a variety of spots on the floor. It's hard to tell from pics about grinding, but it all looks normal.

 

[Baada]

I've done two floors, one with a 10" diamond cup and the other with diamabrush, both rented. The cup left a much smoother profile than the diamabrush and in my opinion seems to be easier to chip off the epoxy when something sharp falls on it. Now they are two completely different floors in different houses so there are many variables that could contribute to that. If it feels pretty smooth you might want to rough it up more with a different grinder but the diamabrush was the better performer for me so it is probably fine.

 

[streetstar]

might be a silly question --- but how did you get the corners?

I am wanting to polish/clear coat my slab, but first i need to remove the existing layer of epoxy (2 part Rustoleum stuff from HD or Lowes -- it has been ok for 8 years now but still does an occasional hot tire pick up)

 

[shaun oriold1]

The floor looks good. Hard to tell as topics are blurry.

I'm not sure the edco will do better. I have one as a backup machine (and to remove old coatings too). It's a workhorse. No matter what I throw at it, it still keeps turning. The 10" disks turn slow through. 230rpm I believe. So they're not super aggressive. I used to use it before I upgraded to the 1900rpm werkmaster. When i used it, I put a couple of pails of sand on the front to weigh it down and it was good. Though slow.

Do a water test and see. If it absorbs you're golden. It looks decent though.

 

[LegacyIndustrial]

Streetstar: a 4.5" grinder with a diamond cup or diamabrush head. May need to use a hand scraper to get that little bit removed in the corner.


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[cabinetboss]

Since my original post I rented the Edco 2 disc grinder and was happy with the result especially the lack of dust vs. the Diamond brush.

I added 2 more picks and tried to get a close up too. There are still dark spots and they hold water alot more then the raw cement (the water test), so I assume its sealer that is deeper or maybe in low spots where the grinders were less effective. They also grind away if I use my handheld 4 1/2 "diamond cup on them however it feels very smooth almost polished so I'm reluctant to try to do the spots with the cup.

can I just go over this floor now how it is or would etching be helpful?