Grinding Floor failure NEED HELP

[Masterfabkirk]

Ive tried to post this twice previously today and it didnt Post.

Bottom line is I spent 13 hours grinding my NEW concrete floor (2400 sq ft) with an EDCO dual head grinder with Diamond blocks. The high areas ground down and removed the top "cream" coat. In the low areas and the majority of the rest of the floor just had surface scratches.

many areas it looked like it ripped up the top coat and left it jagged and fractured.

Now what ?

I dont think spending another 13 hours and $ 500 in tool rental will fix the problem.

 

[ford33]

OP, a location and pictures would be very helpful.

Did you get directions from a coating supplier prior to starting this work? They may have instructions and final finish specifications for you.

All may not be lost.

 

[Armorpoxy]

Hi
2400 sq feet with a rental Edco is too large of an area for that type of machine. The grinders our surface prep division uses weigh well over 1,000 lbs and run on 3 phase power with 30+ hp motors. These types of grinders can get down lower in a reasonable amount of time.

A grinder, especially a smaller one, will do VERY little smoothing and leveling, and since the disks are very rigid mounted they wound get much if at all onto low spots.

Is there a reason why you want you want grind into the aggregate below the cap as normally this is only done if polishing the floor for a salt and pepper look? What are you trying to accomplish as if just grinding for adhesion a light grind and a vacuum is all that is needed?

Let us know more so we can try to give some guidance.

 

[Masterfabkirk]

I just wanted a light grind. I was recommended to use the EDCO by someone who obviously didn't know what they were talking about. After consulting my epoxy supplier and a friend who does this for a living, they educated me on floor grinders and said the unit I used was basically worthless and for small jobs less that 200 sq ft. Thank you for the response, I'm going to proceed with the floor grinder setup Home Depot has. It should fix my issue and open up the remaining top coat areas. Ill try to post some pictures of the failed grind. It doesn't look like I can do that from my phone.

 

[Masterfabkirk]

Any recommendations for a vacuum. I have a 16 gallon shop vac but it plugs up very quickly. Are there high quality vacs to rent that can handle a large volume of fine dust ?

 

[Armorpoxy]

Hi
It’s almost impossible to rent a self cleaning industrial vac. A small one costs over $2,000. Larger ones 15-20k.

Try Sunbelt rentals as they now have dedicated flooring repair stores, perhaps there is one near you.

Also if you are grinding the cap off, that’s too much grinding for a light grind and hitting aggregate really will slow things down.

An inexpensive solution is to get a pre filter ‘Dust Deputy’. This will get 90%+ of the dust out before the vac!

Also NEVER use a grinder with a standard shop vac, they lose suction in about five minutes, and then the dust not being collected slows down signifanly the grinding process. A grinder should always be used with a matching proper industrial vac. If they don’t offer them, then walk.

https://www.amazon.com/dp/B002GZLCHM/?tag=atomicindus08-20

Lastly...2,400 ft best to hire a professional with the right equipment. We keep about 50 men busy grinding and such daily for exactly this reason that it’s too hard to diy.

Below is one of our new 2,300 lb 52” wide grinders...these are the types of machines that make short order of these projects. Unfortunately they cannot be rented to our knowledge. (We name our gear after our employees kids!)

 

[bdk1976]

I've spent an insane amount of time on grinding my 3600 sq ft floor and still have a ton to do. I ended up buying a used ENCO off of craigslist and am doing it in 12x12 sections as I have time. It is taking forever - the hard bond disc I started off with didn't work too well on my 4k concrete but the medium bond disc is doing better but it is still VERY slow.

As far as dust goes, try a dust deputy and 5 gal bucket as a prefilter. I still get a lot in my filter but most of it is caught in the bucket. I can't imagine I'd be able to grind for more than 2 minutes without having to clear the filter if I wasn't using something to capture most of the dust beforehand!

 

[Armorpoxy]

Bdk you may need ‘soft bond’ metal tooling for particularly hard concrete.

Hard concrete=soft bond tooling, soft concrete=hard bond tooling

 

[LegacyIndustrial]

The more you spend on a rental the easier your experience will be. Use a DustDeputy with your shop-vac and be sure to use a fines-bag in your vac.

A “planetary” grinder will give the best, most even and speediest result.

Agree with Armor, our Orlando install outfit uses a specialized-vac just shy of $5K.





Sent from my iPhone using Garage Journal

 

[NitroShark]

I made the decision to pony up $450 and just buy the Dewalt HEPA vac and ground 1585 Sq/ft with it. I filled up several 5 gallon buckets with grinding dust, It never clogged and ran for hours on end.

Now I have a very nice shop vac for my other uses in the garage.

(DEWALT DWV012 10-Gallon Dust Extractor with Automatic Filter)


.

 

[jhelrey]

I'll stick to plain concrete.

 

[Anchorless]

With the Home Depot floor maintainers and the Diamabrush, I found it was far easier and more effective to do a wet grind than to dry grind. Trying to dry grind barely scuffed the floor. I just think the tool works better with water.

The trick is controlling the slurry. I would put enough water down to keep everything wet as I worked on a small section. I would spend about 30 minutes on that section, adding water as necessary, until I felt I had the right profile, and then I would hose the slurry out of the garage.

I used an insane amount of water but I got a profile I felt confident in, and the concrete was very clean after. Very little blowing or sweeping was needed prior to putting down material.