Review / How To Muriatic Acid to Brighten Concrete

[swanicyouth]

I've been wanting to "deep clean" my garage floor for a while. I know nothing about concrete. I mentioned it on here and went to Home Depot, and it seemed like the best stuff out there is muriatic acid. So, I decided to learn a little but about it before using it.

First off, this stuff is a dangerous acid. I usually don't worry about gloves, safety glasses, and respirators with stuff like Iron X or Meg's Chrome Wheel Cleaner because I use it so infrequently and I'm just careful. This stuff scared the crap out of me, so I used gloves and safety glasses. If hydrochloric acid splashed in your eyes it can make you blind - permanently. If it gets on skin it will eat it away.

Muriatic acid is just another way of saying hydrochloric acid. Its a highly corrosive strong mineral acid. Interestingly enough, its used in (part of) the process to regenerate the resin for DI water systems, like the resin used in the CR Spotless. The hydrogen ion is used to remove the calcium and sodium that the cation exchange part of the resin (mixed bed) takes out of the water. this is done so the resin can be used again.

It apparently can be used to "etch" concrete or to clean and brighten it depending on dilution. The cleaning dilution is 12 oz a gallon, so that is what I used. When mixing this stuff, you always add water to acid, so if there is any splash back its likely to be just water.

When I was mixing it, a little bit got on the glove. I knew this because even through thick gloves I could feel it warming up. Even after it was diluted, when being applied to the concrete it started to smoke.

The method I used to apply it was to "broom it on" with a nylon bristle shop broom and scrub it into the concrete. Right away you could see the dirt coming out of the concrete. This was dirt that didn't respond to stuff like Simple Green and surfactant based floor cleaners. The floor was already pressure washed with a "turbo" tip.

Interestingly enough, at this concentration it didn't remove stains. While the overall effect is a brighter, whiter, cleaner concrete - most of the stains are still there. I'm guessing a stronger dilution may help, I may try that in the future. What it did do is just improve the overall look of the floor, which pretty much was what I was going after. But, I was disappointed it did little to the stains, which gives the floor an overall "dirty" look.

Here is some before and after pics. Note the black stain as a reference point. It wasn't removed. Also, note the 50/50 area in the after pic where I stopped applying the product. The area behind (dirty area) is how the floor looked before

Before:

http://img.tapatalk.com/d/13/05/29/a4eru9yv.jpg

After:

http://img.tapatalk.com/d/13/05/29/9u7umaha.jpg

You can see in the after pic if you compare the frontal area how the concrete was brightened quite a bit, but the stain remains.

Another "50/50" showing just how bad the floor was:

http://img.tapatalk.com/d/13/05/29/bu7ady2a.jpg

Here is an after pic of the whole floor. Overall, kind of underwhelming due to the stains remaining. I may try it again at higher concentrations:

http://img.tapatalk.com/d/13/05/29/upe3y3am.jpg

If anyone uses this stuff, be careful!

[FUNX650]

Those stains have leached into the concrete fairly deep, it seems.

In order to remove those stains...
(without having a stronger solution of the muriatic acid take off/etch a layer of your garage floor):

Get some tri-sodium phosphate (TSP), in powdered form,
and use it to scrub the stain.

Sprinkle the TSP over the stain, add enough water to make a paste,
and scrub the stain with a good nylon brush.

Repeat if necessary.

Of course proper PPE is a must.

-"Final-wash" with a household detergent...
Even Dawn will work!! :eek:

Bob

[Anthony@zerboautoworks]

I wonder if TSP would eat up the concrete paint I have on my floor at the shop. I try to keep it clean but I can't control some cars that come in with leaks getting repairs.

[jgg85234]

Muriatic acid is what we add to swimming pools to lower the pH. I always have a few gallons on hand, and have to add it almost every week because of the water in Phoenix. It's not so dangerous when you're adding a quart or two to 27,000 gallons of water.

By itself, it will brighten concrete, but it won't take out the stains.

There's lots of DIY advice on the Internet, and most of them don't work all that well.

As Bob said, TSP will help. But, you need to leave the paste on the concrete. You're trying to draw the stain out of the concrete, not washing it off the surface. Concrete is porous, and oil, grease, etc. get into the concrete.

For a fresh oil spill, nothing works better than kitty litter.

BTW, don't forget to do a "test spot" first :xyxthumbs:

Jim

[jgg85234]

I wonder if TSP would eat up the concrete paint I have on my floor at the shop. I try to keep it clean but I can't control some cars that come in with leaks getting repairs.

My customers with auto repair shops, machine shops etc. use a device they call a Zamboni. The floors are generally sealed with epoxy, not paint.

Search for Zamboni floor cleaners, and you'll find all manner of machines big and small to keep your floor looking good.

If you just search for Zamboni, you'll get ice rink resurfacing equipment (those big machines that come out at hockey games)

The TSP may or may not remove the paint. Do a test spot!

Jim

[Anthony@zerboautoworks]

Well not everybody has a perfect sealed shop floor with epoxy, my floor was extremely trashed with caked on oil grease,etc from 30 years of use and it seemed they never cleaned it, I hit it with degreaser and went to town with a high psi pressure washer and the oil/grease was flying off in chunks I would have spent way to much time and money getting that floor prepped for epoxy on 50x60 building, that is why I painted it with concrete paint.

[MarkD51]

Maybe I could use Muratic Acid to dissolve the Stalagtites on my trucK.:doh:

With the hard water here, and how long I've been living here in NM, I'm surprised my truck isn't bonded to the carport slab.

[Anthony@zerboautoworks]

Not a great before, but you get the idea. I wish I had more pics on how bad the floor was this does it no justice 18621

And after
18620

[swanicyouth]

Thanks for all the advice. I'll try the TSP. I actually had it in my hand and the guy at Home Depot said, "that stuff is OK, but use this".

[mfergel]

I don't know if this would help but I've used this in the past for metal etching on homemade guitar effects pedals. (circuit boards, enclosures, etc). I've done a 1:1 mix with hydrogen peroxide for those. Might want to try that on a test spot.

[jgg85234]

Ah, the wonder of communications on the Internet. :xyxthumbs:

Wasn't picking on you Anthony, just thought I should include the comment about epoxy because that's what's on the floors where I've seen people using the Zambonis. If you research this kind of cleaning device, make sure that what you get is designed for the kind of floor surface you have.

It's obvious from the photos that you did a lot of hard work to clean up that floor.

Best regards,
Jim

[Anthony@zerboautoworks]

Ah, the wonder of communications on the Internet. :xyxthumbs:



Exactly!

I took no offense to what you said.lol

[hollerstiltner]

Nice write up. That stuff can be potent like you said. I have a nice clean spot in the driveway from HCl I used in a battery. I may use it on my porch this summer to brighten it up.

I think you have the mixing order for acid and water backwards. The rule is always add acid to water.

[jgg85234]

Maybe I could use Muratic Acid to dissolve the Stalagtites on my trucK.:doh:

With the hard water here, and how long I've been living here in NM, I'm surprised my truck isn't bonded to the carport slab.

If you paint your truck lime green, it might grow more :poke:

When I moved here to Phoenix, everyone told me how hard the water was (especially the water softener sales people).

It is hard, but I grew up next to Lake Michigan. That water was so hard, that if you dropped it, it would break!

Never bought into the water softener concept. I am trying to figure out what to do to slow up the water spotting when I wash the cars. At this time of the year, it's so dry that water evaporates while you move from one side of a car to the other.

Now that my wife is being a fanatic about her restored old Pathfinder, she points the few waterspots out to me every time. But, she hasn't helped to get it dried quicker.

Jim

[swanicyouth]

I think you have the mixing order for acid and water backwards. The rule is always add acid to water.

Yeah. Your right. I did do it that way per the directions on the jug.