Knocking down concrete splatters

[Sparktrician]

I have a basement job and the homeowner has asked that I knock down some concrete splatters on the concrete floor.  Apparently before the current owner bought the house there was some drainage work done and whoever did it spilled what appears to be hydraulic cement on the floor and didn't get some of it up before it set up, so now there are patches of partially-removed hydraulic cement up to 2mm thick.  These need to be removed before the flooring tile goes in.  I tried using the RO 125 with 80 grit Rubin, but all it did was knock off the high points before the Rubin went smooth.  I shifted over to the RAS with 60 grit Rubin and the same thing happened.  I shifted to 24 grit Safir which was a slight improvement, but it went smooth before much removal was accomplished.  Aside from bringing in an air chisel and making a ton of dust, does anyone have any good ideas for using abrasives to knock this area down? 

 

[RKA]

Ideally I think what you're looking for is a diamond cup grinding wheel (search amazon).  If you're doing a lot of it, Bosch makes a grinder for this purpose that has a shround similar to the RAS to with extraction and contain the mess.  If just a little, maybe attach a diamond cup to an angle grinder, but either way, mask up.

 

[tbellemare]

How about Festool's Diamant?

Tom

 

[chrisrosenb]

+ one on the diamond cup grinding wheel.

If you can find one that fits the RAS, you would also be able to catch most of the dust.

Here is another dust free option that does not cost much more than buying a cup wheel & dust shroud for an angle grinder.
Bosch concrete grinder  

 

[Holzhacker]

I have the Bosch unit. It's perfect for this type of work. The machine is essentially their 4" grinder body with a modified hood and blade attachment. Great for knocking down odds and ends concrete, useless for a whole floor or hardcore work. Wish they'd make the same unit with a heavier motor. DC is very good. Beyond that I would use a 4" grinder with a diamond wheel or masonry wheel.

 

[Sparktrician]

Thanks to all for your suggestions.  Tom, Diamant is apparently NAINA for the RO 125 and RAS (unless you know differently).  I tried a tool rental place yesterday that didn't have the Bosch unit and wanted to rent me a MUCH larger machine for ~$160/day which I politely declined.  I found a reconditioned Bosch unit for $300, so if I can't find a rental, I may just spring for this unit.  Thanks again. 

 

[tbellemare]

I agree that there's no 115mm disks but 150mm disks would work on the RAS.

Tom