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How to remove sealer from concrete

dtam

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Before doing the muriatic acid etch, I need to remove the sealer on the concrete floor in my garage first. Can I use the Klean-Strip paint stripper to remove the sealer? I rather use a chemical stripper than a hand-held angle grinder with diamond wheel.
 
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Edger

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Stripper is fine, just make sure with water after that you have removed it all with no beading of the water. Any small residues should come off with the acid.
 

dcs Inc

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Do it right and grind it. There are soy products that strip well but as with any stripper, it doesn't clean the pores and often leaves a residue. Muriatic acid doesn't cut acrylics, paints or glues or oil based products. It may eat away the surface fines around the stuff thus removing it. Guys complain about tire pick up and pealing epoxies. A lot of it is caused by a cheap product and a lot is caused by poor surface prep.
 

munkey

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The grinding step is not optional. If it works, you could maybe use the stripper to get most of the gunk up so that you are less likely to gum up the grinder, but acid won't help. You are asking for trouble if you don't mechanically remove the topmost layer of concrete. If you don't want to use a handheld grinder, rent a walk-behind grinder!
 

Big-Foot

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Muriatic acid would not barely touch the sealer on my 5 year old floor. I had to have mine shot-blasted. Cost $750 for 1,000 sf. But my epoxy-coat is stuck on the floor forever!!!!
No one in my area does diamond grinding for residential and there were no machines I could rent. That would have been my first choice.
 

dcs Inc

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Shot blasting is the prefered choice. A good spiral grind is next. The problem with grinding is getting the correct tooling to leave scratches and not a slick surface.
 
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dtam

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I'll try grinding then. Is a 4 1/2" hand held grinder preferred over a 7" for better control? Can someone recommend a good hand-held grinder (I don't want to spend the $300 plus on the Bosch concrete grinder) for under $150. The grinders I've seen at Home Depot have RPMs in the 8k-11k range, and from a poster on this forum, 3k is preferred. Any recommendation on where to get the diamond wheel for under $100? I've seen some turbo 24- segment cup wheel on Ebay for $40 from no-name brands, but not sure if these are any good.

I know of a local place (not Home Depot) that has a walk-behind grinder, but it's 200 lbs, and I don't have a truck that can transport it. And I don't want to pay a contractor to shot blast it, so a hand held grinder is my only choice.

Also, I had planned on redoing my driveway (with a contractor) this month, but had it postposed so I can epoxy my garage floor first. I was thinking the degreaser, paint stripper, and muriatic acid would damage my driveway (it'll be colored, and stamped) when washing it off. If I only use degreaser to clean off the oil, and mechanical grinding, can I do my garage floor after my driveway is done?

Thanks for the feedback.
 

PecosBill

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We use walk behinds, or 7" grinding systems. You want a complete system, with vacuum and hood. You should be able to rent one locally.
 

dcs Inc

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The more segments, the smoother the grind. A good all around 7" 12 segment turbo will leave a good profile and not drill a hole in the floor. Stay away from the single or double rows. Way too aggressive and will leave a lot of curfs marks on the concrete. I have a good 12 seg for $65.00. I have more expensive, longer lasting ones but I think this would fit you well. I sell joedue.com stuff and dependable diamonds. You can find cheaper but most of them are of a lower quality. Look for premium cups when shopping.

My grinders and dust shroud are for installer guys so they may be a little high. Grinder, heavy duty shroud and 12 seg turbo cup for around $365.00. 3 year warranty on parts and labor on the grinder. The shrouds last forever.... (well, I can vouch for 9 years on 3 of them). The cup will last several thousand sq. ft.
 

LegacyIndustrial

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Grinding an entire floor with a cup wheel is a real back breaker and you risk creating bite marks. If you are hell bent on grinding it yourself with a hand grinder, go 7", go variable and use a diamabrush hand tool unit. It will help you from beating up your floor.

Naturally the shroud is a must along with a good shop vac.

You will need a couple of filters which will have to be "tapped" every so often to keep the fine dust from accumulating.
 

dcs Inc

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The dust deputy pre seperator really saves on the shop vac, $99.00. The premium 12 segment cup grinder doesn't beat your concrete up as long as you leave the cup flat on the floor. Is it a dance, no but it's not hard to do. Hey scotty, how much is that diamabrush unit for a one time use?
 
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dtam

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Checked Home Depot today, and they just got a brand new Blastrac BGS-250 grinder. They are still waiting for the diamond wheels, and they don't have a rental price yet. It looks small enough to fit in the trunk of the Hyundai Sonata, so I think I'll give this a try first.

Will this also etch the concrete in addition to removing the sealer. Or do I still need to use muriatic acid later on.
 

Big-Foot

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Checked Home Depot today, and they just got a brand new Blastrac BGS-250 grinder. They are still waiting for the diamond wheels, and they don't have a rental price yet. It looks small enough to fit in the trunk of the Hyundai Sonata, so I think I'll give this a try first.

Will this also etch the concrete in addition to removing the sealer. Or do I still need to use muriatic acid later on.

You probably would not need to acid bathe it if you ground it all off, but it's cheap and would ensure that you got any of the residue washed out of the pores of the concrete.. Rinse very well...
 

munkey

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You probably would not need to acid bathe it if you ground it all off, but it's cheap and would ensure that you got any of the residue washed out of the pores of the concrete.. Rinse very well...
Rinsing very well, I agree with... but the reaction of acid with the concrete is going to CREATE residue so I'm not sure how using it ensures anything.
 

Big-Foot

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Rinsing very well, I agree with... but the reaction of acid with the concrete is going to CREATE residue so I'm not sure how using it ensures anything.

My point is/was -
If he misses any spots with the grinder or does not get down far enough to remove the sealer in some spots (maybe a low spot or expansion joint) the muriatic acid bath would certainly not hurt at all. Yes there is residue from the muriatic acid, but if properly rinsed, that will not pose any problems whatsoever.
 

LLONG

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My local rental folks have 7", dual 7" and 12" all walk behind. And they have some units that use bricks instead of the standard diamond. Some with vacuum and some not, so OP it may be worth traveling out of town to get your machine. Rentals are under a hundred including the cutters on the machines(!)

But from the demos i've gotten on these machines appear to leave circular scratches that about 1/32" deep. It seems the final finish would be far from smooth. I'm concerned about the aggresiveness showing in the final fin.

A local paint shop has a really cool machine that i'll call a pulverizer as the cutting heads sort of pound the surface instead of grinding it. I fell in love with it as it doesn't dust much and takes off the prefect amount of surface. But it's $300 a day plus $300 for the cutting heads which they require you to buy new each time !!!!

I have a two car area uncoated that i'm hoping will work with power wash and acid, but i have an attached 16 by 7 shed with a sealer. This shed has wood walls that i don't see how i can wash down with acid or even water. Perplexed on this area. OP sorry for the highjack. Any thoughts? Is it possible for me to grind this shed and simply vaccuum? or do i have to coat and seal my walls up front. TIA!!!!
 

Edger

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As I said previously, if you use a stripper and blast it off with high pressure water you will remove most or all of the sealer. What is left might be more of a residue of broken down sealer, not the sealer itself. That will come off with acid, done it many times. The key is being thorough with both processes.

The problems with grinding come mostly from the hardness of the concrete - too hard and the diamonds will polish and not work, too soft and they will dig in. No matter what number of segments or configuration of them on the wheels or special cost deals etc. A 4.5 inch diamond disc would make a terrible mess of your floor very easily and there is no guarantee with any 7 in disc either. When you rent, the diamonds might be just right for your floor and they might be useless, you take a risk.

The Diamabrush system is the only grinder that is different because it does not matter if you have hard or soft concrete and it does not matter what sealer you have. The unique design of the diamond blades means that they will always cut well and they will not dig into your floor easily either, and you may get away with 4.5in. I would recommend a Dust Deputy as a good separator, but how much do you want to spend? Is the stripper low cost enough? Can you afford a grinder, dust shroud, discs, vacuum and dust deputy?

Here is some info on diamonds for hard or soft concrete. http://www.situp.com.au/Grinding Hard Concrete.html
 
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dtam

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Edger,
Several other posters on this thread have said grinding is not optional. I also don't have a pressure washer to wash off the residue. I don't want to spend more than $400 on preparing the concrete. My options right now are (in order of preference):

1) have a contractor do it, includes diamond grinding (not sure if it's diamabrush) and pressure washing ($400)
2) rent Blastrac walk-behind grinder from HD (no idea what it'll cost)
3) 7" grinder, 7" diamabrush, dust shroud (~$400)
4) 7" grinder, joedue.com 7" 12 seg turbo cup, dust shroud (~$300)
5) paint stripper, muriatic acid, pressure washer (~$400)
 

Edger

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dtam,

Without a pressure washer I would not strip and acid etch. If someone can do it for $400, that sounds the best option. Diamond grinding can be simple or it can be a nightmare depending mostly on the hardness of the concrete, not the type of machine you use. It is OK for a contractor because he has several machines and several types of diamond segments or cupwheels so he can change those according to the job. When you only have one choice because of your purchase or because of a rental machine you are unfortunately taking a big chance.

Diamabrush have been getting a good rap here because they eliminate many of the problems caused by diamond grinding - easy glue and sealer removal, cuts hard concrete, does not leave heavy ring marks, however I am unsure of the wear rate and therefore the cost. A poster yesterday said they used up a 7" for only 125 sq.ft. which is very expensive. Maybe he used it inefficiently compared to a contractor, maybe not.

If you go for a contractor ask to see some other jobs or get it in writing that he will prepare the floor for coating and the processes he will use. Use water to test for beading before paying him, there must be no residue left.
 

Brian_B_

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Before doing the muriatic acid etch, I need to remove the sealer on the concrete floor in my garage first. Can I use the Klean-Strip paint stripper to remove the sealer? I rather use a chemical stripper than a hand-held angle grinder with diamond wheel.

I do not mean to hijack this thread. I just wanted to know how you could tell if the concrete had sealer? Do you have pictures?

This grinding every square inch sounds like a very expensive, time consuming, and possibly damaging proposition I was not aware of (until I started reading this forum) to put epoxy on the floor.
 

Big-Foot

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I do not mean to hijack this thread. I just wanted to know how you could tell if the concrete had sealer?

Throw a glass of water on it. If the water beads up or does not soak in, it is sealed.. Compare to the sidewalk in front of your house..
 
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dtam

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My local HD just got a diamabrush 16" concrete prep tool, and that's what I ended up using this weekend. 24-hr rental cost: $55 for diamabrush, and $42 for Clark floor maintainer. Very easy to use, and leaves a nice surface (like 150-grit sandpaper). The diamabrush was brand new when I got it, and after 6hrs of usage (about 10 passes, but probably not necessary), it still looks new, so I don't think it wears out fast. Water doesn't bead up anymore, so I know the sealer has been removed.
 

Brian_B_

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This is what you rented?

It says "Clarke American Sanders Floor Maintainers"

I thought they meant using a grinder and some sort of attachment.

That looks like a floor buffer to me. What am I missing? :headscrat

That would not be so bad, if that is what you use. I was going to avoid epoxy if I had to be on my knees grinding for days\weeks (plus buying a big adjustable speed grinder).
 

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dtam

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Brian_B:

That's exactly what I rented. It is a floor buffer, but you can put in different attachments like the diamabrush. I also wet the floor when using it so it was dust free, but made a mess along the lower part of the walls. Not sure if you can do the same with a regular walk behind grinder.
 

LegacyIndustrial

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Here is a pic of the diamabrush in action on a standard buffer.
photo%25287%2529.JPG
 
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dtam

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Scott:
I got the HD-105 to repair some cracks, but was wondering if I can also use it to cover the exposed expansion joint at the edge below the footing as you can see from the pics.

Thanks.
 

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LegacyIndustrial

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I like the gel crack filler for that.
The HD105 will not elongate and could crack if there is any expansion/contraction.
That said, I have used it that way in the past, on older slabs with good results.
 

lasvegas28

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The main problem you face is removing the existing sealer without damaging the colored concrete. This may be difficult depending on what type and how the coloring was added. If it is just on the surface (cast on color hardener, acid etching color) you can pretty much guarantee it will be damaged to some extent. For integral color (dye added to the concrete while still in the mixer truck) you should be fine.

Xylene is the most commonly used stripper for acrylic sealers and is very effective. Be careful, your future children might regret it if you drink any of this stuff. The soy or other "natural" strippers are fairly effective on water based sealers, but require more elbow grease.

After it has been removed, pressure wash your concrete to make sure it is clean. Wait until the slab is dry. By "dry" I mean DRY. Duct tape a 2 foot square of plastic to your slab for 24 hours. If any water drops are under it, you still have water vapor escaping and need to wait longer. Any water on or in the surface of the slab can turn acrylic sealers white.
 

lasvergas501

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Concrete sealers protect the surface of the concrete from stains and excess moisture. Concrete itself is very porous, containing thousands of tiny holes. These tiny holes ****-in and retain any moisture, stain and spill on the unsealed concrete, hence the need for a concrete sealer. Removing the sealer applied to the concrete surface can be a very time consuming job when done correctly, even with the use of the proper supplies
 

SapesOfIndia

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My local HD just got a diamabrush 16" concrete prep tool, and that's what I ended up using this weekend. 24-hr rental cost: $55 for diamabrush, and $42 for Clark floor maintainer. Very easy to use, and leaves a nice surface (like 150-grit sandpaper). The diamabrush was brand new when I got it, and after 6hrs of usage (about 10 passes, but probably not necessary), it still looks new, so I don't think it wears out fast. Water doesn't bead up anymore, so I know the sealer has been removed.

Does this help sand down minor bumps to make surface flat?
 
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