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Can I grind a floor with a 4.5 inch angle grinder?

mktbully

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Got a small garage i'm looking to epoxy. Can i use a 4.5 inch grinder with a diamond cup/wheel to grind the floor or do i have to use a full size grinder? i know the small grinder will take me a little longer but i'm not in an hurry.

when i'm grinding what should my end result look like? am i grinding the stains out? any pics?
 
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boiler7904

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Not if you want a flat floor. You'll grind some areas more than others by default. Bigger grinder means less deviation from the target measurement.

Don't forget that you'd have to have some sort of dust collection.
 

35mastr

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You can rent a floor grinder for peanuts.Why would you want to be doing that on your knees and sucking up all that dust.
 
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mktbully

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is the grinder available from Home Depot/lowes for rental?
What do i need to get?
 

35mastr

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is the grinder available from Home Depot/lowes for rental?
What do i need to get?

I dont know if the box stores rent them,But I would inquire.

Just tell them that you need to rent a floor grinder for cement.

We have equipment rental places here that rent them.

A freind of mine did alot of body work and painting in his garage.His floor was a mess.

He rented a floor grinder and took just a layer off the top.

Looked like a freshly poured floor after that.

Here is a link as to what they look like.

http://search.live.com/images/results.aspx?q=cement+floor+grinder&FORM=BIRE#
 
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wuneyewilly

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How do you get into the corners and will the rental grinders get all the way into the corners up to the foundation?

Did that guy just leave it freshly ground, no topcoat with a product? Any drawbacks to leaving it if you arent spilling or dripping oil, etc
 

35mastr

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You could just leave it.But it will eventually get dirty and stained again.

Just with traffic its going to end up dirty.

Why go through all the trouble of grinding the top off if your not going to protect it.
 

jocool1585

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Not sure where you're located, but a rental shop like Grand Rental Station will have an Edco Floor Grinder. They've got different grinding head attachments. They'll take the floor down about 1/16" to 1/8" at a pass. Make sure you use water with the machine.
 

JD in DFW

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Not sure where you're located, but a rental shop like Grand Rental Station will have an Edco Floor Grinder. They've got different grinding head attachments. They'll take the floor down about 1/16" to 1/8" at a pass. Make sure you use water with the machine.

I would pass on the water usage with the grinder. A good vac system and shaking out the filter into a trash bag a few times during the process would be more then adequate. Use a 7" or if all you have is a 4" on the edges to kiss the stem walls. You will have to rent the diamond insert blocks with most grinders which is really the best way to go.

If you have never used a machine like a gas pr even the smaller electric concrete grinders take some time to "test" and practice with it. Go with a small 10" grinder if I were you.....the bigger 24" dual disc grinders can and will dance on you like a fat chick at the prom!

Good luck with your garage...and have fun with it!
JD
 
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mktbully

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well what's my other alternative? can i just acid etch and go from there?
is grinding a must? the floor is not THAT bad. there's some spots where it's worn down by the tires but other than that there's some stains and a few small blobs from cement not cleaned up for smoothed out. keep in mind it's about 70 yrs old.

i'm in the NY metro area.
 
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thegarageguy

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See if there is a place that can rent you a Hilti Dg 150 with vac. Google it in your area. That hand grinder is a monster! IMO, Edco rental equipment *****. Also you can contact a local Benny Moore, some rent Master Craft 16 inch walk behind grinders. They relabel them as ONfloor system. Make sure you use the red diamond, unless you have a coating then you'll need the toothed attachment. Good luck.
 

nickwrx

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I am in the same boat, only my floor is terrible! It wasn't smooth finished and it even looks like they tried to put a top coat on it. Its all uneven and flaking off in some spots.

Would I go with a big walk behind in my case? Its a 2 car with a shop in the back. So there is some good square footage to do. Not to mention a lot of grinding to be done! And like someone else said, what about the corners? Should I rent a small one for the corners?

And any specific type of grinding wheel/diamond?
 

5Cent

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Sure you can....I don't see what the big deal is. Here's a link showing what I did with my 4.5" grinder.

http://www.garagejournal.com/forum/showthread.php?t=23761&highlight=epoxy-coat

I searched around the area, but wasn't about to pay what they wanted to rent a grinder for the day. My garage is roughly 19x19 finished and it took about 4 days to finish. I did one section at a time w/o a dust collector so it can be done!

W/O using a dust collector, I just kept a fan at the end of the garage to blow it out of the door opening and wore a respirator and goggles. Take your time and you'll be fine, good luck!
 
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mktbully

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Sure you can....I don't see what the big deal is. Here's a link showing what I did with my 4.5" grinder.

http://www.garagejournal.com/forum/showthread.php?t=23761&highlight=epoxy-coat

I searched around the area, but wasn't about to pay what they wanted to rent a grinder for the day. My garage is roughly 19x19 finished and it took about 4 days to finish. I did one section at a time w/o a dust collector so it can be done!

W/O using a dust collector, I just kept a fan at the end of the garage to blow it out of the door opening and wore a respirator and goggles. Take your time and you'll be fine, good luck!

i think my garage is even small than yours...LOL
i guess i'll check on the rental prices...if it's up there then i'll give the 4.5 inch grinder a whirl. any reason why you didn't wet the concrete for the grinding? wouldn't that keep the dust down?
 

5Cent

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Local rentals for a 7" standup model grinder was $110/day....i ended up just buying a 4.5" diamond grinder and have used it on other projects already.

I did try wetting the floor when I first started, but you'll find that the slurry is just a pain. As the moisture is trapped in the continuous dust being created, I would lose track of where I was at and was actually tougher to clean off the surface then the dust.

I only needed to take off the top surface as the floor was only 5yrs old, but had a sealer on it. I really enjoyed doing it w/ a 4.5" grinder as I could see up close what the texture and profile was.

Here's the pics for easier viewing:

Before:

100_1163.jpg


100_1164.jpg


100_1165.jpg


After:

100_1213.jpg


100_1216.jpg


100_1217.jpg


100_1218.jpg


100_1229.jpg


100_1233.jpg
 

thegarageguy

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Sure you can....I don't see what the big deal is. and it took about 4 days to finish.

You can also grind it with a dremel in about a months time but most peoples time is much more valuable. No one said a 4 inch grinder was impossible, just retarded when there are better tools for the job. BTW, a fan is great to circulate air but you will still need to vac up the concrete to eliminate any dust from settling into the pores that you just opened up.
 
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5Cent

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You can also grind it with a dremel in about a months time but most peoples time is much more valuable. No one said a 4 inch grinder was impossible

Please reread my OP:lol_hitti

1.) Never said it was impossible. What one deems retarded maybe the only option for others. It was not my only option, but it was an option I felt more comfortable with in both cost and process. The OP was in regards to using this option, so the question was answered with regards to that.

2.) Fan was used to evacuate the dust to outside, not circulate it in the garage.

3.) Never said anything about cleaning the floor in regards to not using a dust collector. As with any prep job, there are multiple ways of cleaning the floor and it is always advised to vacuum and powerwash a couple of times.

4.) Now that the hair-splitting is done, I'm going back to this:beer:
 
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sammerdog

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Nice floor 5cent. I'm leaning towards doing the same thing (up here in Michigan, if there's one thing we have too much of it's time) and using a 4.5" also. Thank you for the tip on limiting water usage.

After you ran your wheel over your floor, did you then hit it with muratic acid? Water? Something else? What did you use for floor paint? I see the A & B buckets in the background, but not a paint mfr.... Does your paint seem to be holding up well after the winter months?
 
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5Cent

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Nice floor 5cent. I'm leaning towards doing the same thing (up here in Michigan, if there's one thing we have too much of it's time) and using a 4.5" also. Thank you for the tip on limiting water usage.

After you ran your wheel over your floor, did you then hit it with muratic acid? Water? Something else? What did you use for floor paint? I see the A & B buckets in the background, but not a paint mfr.... Does your paint seem to be holding up well after the winter months?

I completely understand the situation you're in. I was ready to get it done, but wanted to make sure I had all possible information before starting. I have never ground concrete before and wasn't really sure what to expect. With that being said, I wasn't sure how much the 7" or larger commercial grinders would remove and I wanted to be in control of it. After weighing all my options, I bought the 4.5" diamond grinder wheel for around $70 IIRC,and as I have said, have used it on multiple other projects. This was all done on my generic variable speed (RPM) grinder that i picked up from Autozone while in college a few years back.

Process wise, here's what I did.

1.) Not knowing what was on the floor, even though only 5 yrs old I knew it had to come off. I tried Muractic Acid (bought at Sams, which had 2 (1) gallon jugs). It barely reacted and the surface was no more coarse then starting.

2.) Time to grind. Did my research on grinding, got prices and moved foward with 4.5" wheel.

3.) Started in corner, played with RPM setting for best texture/ease of use and went to town. The dust was nuts so I tried adding water. I sprayed the area I was working in. Right away I thought this was the way to go, but the slurry became so thick that it was difficult to see where I had done. If I wanted to see, then I would have spray it down again, and now there's slurry all over the place. Not only that, I had to spray it all the way out of the garage (started in back corner), so I got out the fan and just dealt with the fact that it's going to be dusty:bounce:

4.) After garage was ground, I used the muractic acid 2x more until there was little to no reaction. I then powerwashed it 2x and let it dry. The next day I came back and powerwashed it again and let it dry. It dried for I think a day or so then went to putting down epoxy.

5.) What you are calling paint is actually epoxy. It's solvent based and made by epoxy-coat (www.epoxy-coat.com). If you do a search you will find plenty of information on this product. This was done almost 6 months ago and I'm do for an update thread. It's held up great and I HIGHLY recommend the product to anyone looking to do an epoxy floor.

Where abouts in MI are you at? If you're ever down in northern, oh and want to check it out, feel free to let me know.:beer:
 

sammerdog

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Thank you for the info 5cent. I think you did a good job without going overboard on rentals, etc. My concrete is 16 years old, but in good shape. I'm planning on a quck "skimming" of the surface with a wheel. Some guys are saying to grind down 1/8" or so. Seems like overkill to me. Just like you did, follow it up with 2 hits of muratic acid, then epoxy.

I'm kinda rough on the garage floor, so I'm leaning towards a cheaper epoxy like Rustoleum makes. That way if I trash an area, my wallet won't hurt quite as badly when I have to touch it up.

Thanks also for the invite - I'm way over on the far side of Michigan by Lake Michigan though. Mrs Sammerdog has relatives a little west of you in Clyde and Green Springs. I do blow past you on 80/90 a few times a year when we head to the east coast. I'll honk next time I'm going past... .....so if you hear a horn off in the distance.....
 

5Cent

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Thank you for the info 5cent. I think you did a good job without going overboard on rentals, etc. My concrete is 16 years old, but in good shape. I'm planning on a quck "skimming" of the surface with a wheel. Some guys are saying to grind down 1/8" or so. Seems like overkill to me. Just like you did, follow it up with 2 hits of muratic acid, then epoxy.

I'm kinda rough on the garage floor, so I'm leaning towards a cheaper epoxy like Rustoleum makes. That way if I trash an area, my wallet won't hurt quite as badly when I have to touch it up.

Thanks also for the invite - I'm way over on the far side of Michigan by Lake Michigan though. Mrs Sammerdog has relatives a little west of you in Clyde and Green Springs. I do blow past you on 80/90 a few times a year when we head to the east coast. I'll honk next time I'm going past... .....so if you hear a horn off in the distance.....


No problem, but I will advise you to go the epoxy route over a paint. As I said I used epoxy-coat products and it is holding up great. I just did two complete brake jobs on the Explorer and Duramax and it only suffered a few scratches. These are barely visible (mainly from jack/jackstands/metal particles) when the floor is clean and it still looks great!

I think you'll be hurting the wallet more on fixing your painted floor more often then having to do anything to an epoxy floor as it will take alot to damage it.

Small world, I'm originally from Sandusky, but worked in Fremont for 2 years and drive through Clyde/Green Springs all the time. The offers always there to take a peak. Good luck!
 
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