Diamond grinding cup


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18 Jul 2016
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I want to redo my concrete garage floor and :
- Grind high spots
- pour self levelling compound
- put some underlay
- install some PVC tiles

in order to grind the high spots, I was thinking to use a grinding cup.


I contacted Makita UK and asked them if it was usable in their standard angle grinder (GA5030), and they told me that no, it is only for concrete grinders, not angle grinders (yet their website states that it is suitable for angle grinders :unsure:).


Same remark with Srewfix Q&A. In the description, they state that it is suitable with every grinder, yet in the Q&A they say it is not suitable for Makita grinders :unsure:

After checking the user manual, it states that the angle grinder GA5030 shouldnt be used with stone cup wheels (which I believe are completely different things than a grinding cup).


Does anyone have experience with this kind of diamond grinding cups ? And has anyone used it with a Makita grinder ? (their technical support contradict their product page, so not sure they are reliable).

I have a little Makita battery powered angle grinder ( about 4") and have used it with a diamond cup similar to the one you showed, with no problems so far. I was mainly grinding sandstone with some concrete and brickwork all outside, lots of dust. I have used wall chasers (angle grinder with two cutting discs and dust extraction facilities) inside without dust extraction after a few seconds I could not see the wall. It does have a filter on the cooling air inlet though.
Given the low price of wheel and a cheapy angle grinder I'd just give it a go. Throw the money at a serious dust mask setup, you'll need it!
Many years ago I used a stone cutting disc in a circ saw to cut brick pavers. The stone dust got in the motor bearing and caused a melt down. May be why they say use a concrete grinder.
I have hired a concrete floor grinder in the past - make sure you hire the biggest vac they make available for it - the amount of dust produced is unbelievable.
It did a good job, though.

IIRC the diamond disc was measured before and after and I was charged per mm used.

You could use those stone grinder discs in any angle grinder for a little bit of smoothing a small area, but it would be hopeless for a whole floor

Ive just done a fair amount of concrete floor grinding, I used an old Black and Decker angle grinder which takes the more common 115mm discs, buy the 115mm Dimond Cups that look just like your segmented ones from Amazon, cannot recall exact price but around £5 or less gets you one and to my surprise the quality is pretty good and they last. One thing I did find however was that they dont screw onto the shaft, you secure the cup with the screw on flange like you would an ordinary disc, the only issue is be prepared that you might need to pop a washer under the flange because the flange might foul the sides of the cup before it bites down properly on the disc, this was the case on both my grinders. One thing you def want to do is to knock up some kind of dust shroud, I used the bottom of a plastic container and very loosely secured it by putting it behind the disc guard, and I found a bit of flexi hose which was let into the top, this connected to the hoover worked far better than you could immagine. It sounds complicated but it was just bits held together with gaffer tape. I think its possible to buy one but they were quite dear. But all in all it worked really well.
This is the kind of thing your aiming at making, perhaps use a plastic flower pot dish as the starting point, remember it doesnt want to be a tight or good fit around the angle grinder because it will not work well if it cannot be drawing air in and it want to suck the grinder onto the floor, nice and flappy worked well for me.


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Thanks, I've seen those and will probably get one once i decide to go ahead with grinding the garage floor.

I initially thought about grinding the whole floor, and rent a professional machine to do so. But considering the price, and the poor state of the floor, I will just grind the high spots and pour some self levelling compound.

So an angle grinder with an appropriate dust shroud and vacuum should do the trick.

Next step is to figure out if pouring self levelling compound on a slopped garage floor is a good idea :unsure:
Well self levelling will puddle up,,,obviously depends on the state of the floor but could you knock of any reay high spots, fill holes with SL and then go from there, celotex covered in flooring chipboard can work very well for instance.
I will not remove the slope, but just put SLC to have a flattish floor, then put some liquid DPM (it looks like some moisture is coming through the concrete slab, not 100% sure but looks like it), then put some underlay and finally some PVC tiles. Should make the garage/workshop a bit more comfy.