Grinding concrete

[trpearcy]

Hey folks. I’m sure I could google this and get info, but it’s been a while since I’ve been on here, so I’m gonna bother you folks.

What grinding disk do I use to level out some small sections of concrete? My lift arms drag on little sections that are slightly higher. It’s not the lift. I installed it, and it’s as level as is physically possible. It was the people that’s put the concrete in. They didn’t smooth out this section enough, and you can see higher sections in it.
So today I was in a mood, and I grabbed by 4 inch grinder and started at it, to see if I could get rid of the high section where the arm rubs. Pretty much just smoked the grinder disk. It’s a Norton Steel/stainless grinder disk.
So what grinder disk do I get? Or is there a better way to do this?

 

[HMCFab9]

You can buy specific concrete grinding wheels.
They work great.

 

[jshillin]

If you want to try to just take those small spots down with a 4" grinder, you need a diamond cup wheel.

https://www.homedepot.com/p/RIDGID-4-in-Double-Row-Diamond-Cup-Wheel-HD-AWD40/202884364

 

[Kaizen]

If you want to try to just take those small spots down with a 4" grinder, you need a diamond cup wheel.

https://www.homedepot.com/p/RIDGID-4-in-Double-Row-Diamond-Cup-Wheel-HD-AWD40/202884364

This will do the job BUT test on another piece of concrete. I was shocked at how fast it digs and how fast it gets away from you. gentle flat contact is the goal. done in 30 seconds

 

[4x4Petr]

What's up with the telephone pole so close to the lift? Dosen't it interfere? To fix the floor I would use a concrete diamond cup. Gently Bentley is the rule of the day.

 

[Parrothead]

If you want to try to just take those small spots down with a 4" grinder, you need a diamond cup wheel.

https://www.homedepot.com/p/RIDGID-4-in-Double-Row-Diamond-Cup-Wheel-HD-AWD40/202884364

This will do the job BUT test on another piece of concrete. I was shocked at how fast it digs and how fast it gets away from you. gentle flat contact is the goal. done in 30 seconds

That’s exactly what you want, and it works great!

Kaizen is 100% right, it can chew through concrete pretty quickly. I used that 4” to take off 2”+ of a 18”x30” block of cement. It can make a very smooth surface if done right.
M

 

[WVBrady]

You can buy specific concrete grinding wheels.
They work great.

Bee sure to use a good mask; you don't want to be breathing that fine dust.

 

[anythingyoucanimagine]

This will do the job BUT test on another piece of concrete. I was shocked at how fast it digs and how fast it gets away from you. gentle flat contact is the goal. done in 30 seconds

That's what I was thinking too. Flat wheels for chimney pointing really dig if you aren't careful. Pretty sure they are same thing just different shape.

 

[Fix Until Broke]

What others have already said, you need a diamond cup wheel - Don't be afraid to put a 7" or 9" diamond cup wheel on a 4.5-5" grinder. This will give you a flatter finish and do a better job of smoothing out the high spots. I've done this several times on floors, walls, sidewalks etc. Never stay in one spot - always keep it moving.

The dust is no joke either - if you're doing this inside, you'll be in a white fog in seconds and a layer of dust on EVERYTHING. Ear plugs/muffs and a respirator (not one of those white masks, a full face sealing respirator like you use to paint a car) are required. Having someone standing nearby with a garden hose to keep the area flooded works very well to keep the dust down. There will be a lot of "splatter", but that cleans up much easier than all the dust.

 

[trpearcy]

Ok, thanks for the info everyone. I will pick up a diamond cup wheel and get that smoothed out, and I’ll use a dust mask and make sure to keep it moving and go slowly.

The phone pole is kind a long story. The guy that built the garage back in the 80s built it with phone poles. It’s a pole building, just with phone poles from the local power company. He worked for the company, and somehow got about 50 of these poles to build the garage, and then apparently on a holiday weekend brought home a truck to set them

 

[Homerr]

The diamond cup wheels are great and I echo all the PPE comments. And seriously consider one of these for dust control.

https://www.amazon.com/dp/B01N7ONJUA/?tag=atomicindus08-20

I ground my basement down for epoxy and used a diamond cup wheel for the edges, this reduced the dust by 95%. Near the end of the grinding in a 14'x32' space I saw one small spot that needed grinding and I was lazy and didn't drag the shop vac over to hook it up. About 5-6 seconds of grinding and the basement was a fog of dust and I could barely see. The dust ain't no joke. I also ran a Dust Deputy between the grinder and the shop vac and that greatly extended the filter life, probably not necessary for this project unless you already have one.

 

[Armorpoxy]

Agree, Diamond Cup Wheels...

 

[Badbob1919]

Make sure it’s a cup, not just a segmented flat wheel or you may not have enough knuckle room to operate the trigger! (Funny but you know At the time its not funny) I run grinders nearly everyday. Some cups have large segment, some small. If you look real closely at the embedded diamond, and their volume, you can tell a good wheel. Some cups bind up with **** after a while and glaze up. Just find you some blacktop, hit it for 2 seconds and your back in business! I typically use cordless for corners, so it’s easy to find blacktop! I prefer AM/PM while I’m filling up! LOL

 

[LegacyIndustrial]

Our install company runs a dust-deputy on the solids collector and it reduces the amount of dust getting to the Pulse-Bac by about 95%. For the DIY it is a saving grace and not very expensive.

Check this video: https://www.instagram.com/p/BQ6pc8Eg0I-/

Sent from my iPhone using Garage Journal

 

[sweetk30]

all has been said here already .

dimand cup wheel .

eats FAST so keep it moving .

tons of dust . when i did my 1 small spot i had a 42" barn fan going just behind me and the guy next door come over as he was thinking my shop or something in it was on fire from the massive dust cloud coming out the shop door .

use a good size grinder as they eat power . my hitatchi 9.5 amp unit did just fine .

 

[cherniavin]

You can buy specific concrete grinding wheels，and longer size screws, then place the chassis and re-fix.
They work great

 

[Suzy Greenberg]

What others have already said, you need a diamond cup wheel - Don't be afraid to put a 7" or 9" diamond cup wheel on a 4.5-5" grinder.

That is an interesting idea. Won't that bog down most smaller grinders or I should be going with light pressure anyway? It would be great if not having to rent was actually an option.

 

[Fix Until Broke]

I used a Milwaukee 2783 4.5-5.0" M18 grinder with a 9.0 battery. You can't lean into it like you can a full size 15 amp 9" grinder, but it's still very effective. There is a "start up" procedure though. Hit the trigger for as short of a time as you can to just get it spinning, then hit it for another second to get it spinning faster, then you can hold the trigger on and it will ramp to full speed. The electronic circuitry will kick it out if you just pull the trigger and wait. I also used a 120v Milwaukee 4.5" angle grinder 8 amp version and it worked similarly.

Be careful of the gyroscope effect of that big wheel - hold on to the grinder with both hands and pay attention. You'll see what I mean once you fire it up and try to move it in free air.

I did all the transitions between my sidewalk sections so the snowblower wouldn't catch on them in the winter. Waited until it was a nice windy day, stayed up-wind and ground them all down - I live on a corner so probably 30 seams or so?

I wouldn't recommend doing a big job this way, but for small work that you can take your time with - absolutely.

 

[jarhead]

old post, yes i am aware...

Can a 1" lip 1-2" wide be ground using above methods? Or should i rent a walk behind? It's about 3' long
Thank You

 

[tncatadjuster]

They can remove quite a lot of material, with lots of dust though.

 

[Fix Until Broke]

Yes - you can do a 1" lip, 1-2 inches wide by 3' long. You'll spend more time effort renting a walk behind than doing it with a grinder like above.

 

[Codyboy]

Ok, thanks for the info everyone. I will pick up a diamond cup wheel and get that smoothed out, and I’ll use a dust mask and make sure to keep it moving and go slowly.

The phone pole is kind a long story. The guy that built the garage back in the 80s built it with phone poles. It’s a pole building, just with phone poles from the local power company. He worked for the company, and somehow got about 50 of these poles to build the garage, and then apparently on a holiday weekend brought home a truck to set them

Power companies do not use telephone poles.