Muriatic Acid effect on steel workshop

[Texas442]

Looking to epoxy coat a 2500 square feet ALL STEEL workshop. It's a typical metal framed building with steel sides.

I've done this over 12 years ago on another shop, but noticed few years ago slight rust around the perimeter on the building. This time, I want to do it right and not take a chance on any future rust.

Would like to hear opinions on some of the alternative chemicals. Thank you in advance.

 

[Shea]

If you grind, then you will not have to worry about the fumes from a typical acid etch affecting the metal. Another alternative is Surface Gel Tek in Medium. It has no VOC's and can be neutralized and flushed into the sewer with water.

 

[LegacyIndustrial]

Grind.


Sent from my iPhone using Tapatalk

 

[Warrenator]

Years ago when I was working in a lab I was using hydrochloric acid (common name is muriatic acid) for something or other that involved lots of bubbling and reacting. Several benches over one of my fellow lab rats was using a bunsen burner (open flame) and was wondering why the heck all of a sudden there were little sparkles in the blue flame of the burner..... it was little bits of acid I was throwing into the air and had traveled 30 feet over to her bench! (I should have been working in a fume hood, ooops)

Anyway, the point of all that is, any muriatic acid you use will cover everything, and I mean everything, in the building with a tiny bit of acid. Certainly enough to cause corrosion for years to come if not removed.

 

[Texas442]

Thank you all for your input.

 

[ZRX61]

I'm not following.... Are you saying you want to clean rust off the building with acid before epoxy coating, or are you asking if epoxy will protect the steel from the effects of the acid?

 

[4 FN 27]

There are 3 things I don't let near my Fabrication Shop:

1. Any kind of Acid.
2. Any kind of Silicon Spray.
3. A politician.

The fumes from acid will begin rusting anything ferrous. It will also attach anything aluminum.

I do not recommend!!!

 

[LXCam]

I'm not following.... Are you saying you want to clean rust off the building with acid before epoxy coating, or are you asking if epoxy will protect the steel from the effects of the acid?

You can prep a concrete floor in a couple ways. One is to use caustic flake, it's a emulsifier that will draw the oil out of the slab, then use murietic acid to etch the floor. This will remove the latent loose material and allow for a better bond. But a mechanic prep is way better then that old method. I worked in the industry for a couple of years 30+ years ago. All the **** is just as nasty as you can imagine. More then once I got the caustic down in my boots and wound up with down to the meat chemical burns.

 

[Texas442]

I'm not following.... Are you saying you want to clean rust off the building with acid before epoxy coating, or are you asking if epoxy will protect the steel from the effects of the acid?

Sorry, allow me to clarify.
Building#1 was completed over 12 years ago: I used the acid to prep the floor before epoxy coating. I did all the work myself and tried my best to keep the acid from the perimeter of the STEEL siding. I thought I rinsed everything very well. I then epoxy coated the floor and to this date, the floor looks great. Few years ago, I noticed that the STEEL siding and the STEEL columns are showing signs of rust at the base where the STEEL meets the concrete floor. I am guessing that the rust is due to the acid that I applied 12 years ago, but I am not 100% sure.

Building#2: This is a brand new building completed 1 year ago. The floor is still bare concrete. I plan to epoxy coat it myself later this summer. I will not use the same stuff I used on Building#1, so I am looking for alternative chemicals.

 

[rburke65]

Could it possibly be a reaction of the concrete against the metal?

 

[nh_yota]

For a few seconds there I thought you were going to apply the acid to the steel building before you epoxied the building.

 

[BoostAddiction]

Sorry, allow me to clarify.
... I will not use the same stuff I used on Building#1, so I am looking for alternative chemicals.

Why use chemicals at all? The safer, easier method is just to mechanically prep it with grinding or sanding.

Like the others, I would never use that kind of chemical in the shop.

 

[Armorpoxy]

We have seen acid affect metal walls, so we would never recommend using it. Best to mechanically prep/grind this floor.

 

[Cave Creek Ray]

Texas,

I used an acid wash to loosen the creme on my slab after an epoxy failure in my last house. The fumes, though light, started some surface rust on my steel tools in the shop. Fortunately, light oil and fine steel wool took the rust off. The acid got the creme up and I had great adhesion the second time around.

As for your older building, howsabout getting a gallon of the rust converter (WD makes one that sells at WallyMart for $20) and putting it in a pump sprayer to hit your old steel? Its fairly inert and should wipe up after it does its magic. Supposedly, once converted, the metal wont rust again. I think most turn the rust black.

As for loosening the creme on the new slab, you could try a high pressure washer (well above 3000 psi) with a rotary spray head that rolls along the floor. They really loosen creme well in most installations and, except for getting wet, you should be plenty safe.

Like you Texans need any more water!

Another less attractive alternative is dry-sanding. I am getting ready to tile my house garage and need to scuff off the old garage floor paint before tiling. The Rental guys at Homey 'Po recommended a floor polisher with some 40 grit pads for my application. That would probably be a little too rough for re-painting unless you go really high solids or two-coat it. You can get finer grits for final sanding.

Good luck and post some pics!!!

Ray

 

[Randy B]

Muriatic acid and concrete makes acetylene gas,well ventilated and open flames extinguished,i.e hot water heater.

 

[EdT]

In my experience, hydrochloric acid(muriatic acid) will make steel rust while you watch. It is very aggressive. The rust on the lower part of your building could be due to the cleaning 12 years ago, but more likely it may have been started by that and is now blossoming due to years of condensation where the steel meets the floor. The floor is often cooler than the surrounding air, the steel is chilled by the concrete and moisture condenses on the steel where it's cooler than the dew point.

 

[tlmartin84]

Was the original floor and walls neutralized with a baking soda rinse afterwards?

The concrete will typically neutralize the muriatic acid which is why you can get away with just rinsing. However on metal nothing neutralizes it so it keeps eating away. I use muriatic acid to clean steel with, it works fast, and unlike phosphoric acid it does not leave the zinc phophate behind. You do however have to soak the metal in a bath of baking soda. I do it until I no longer see a reaction and then some.

Then I pull it out, dry it and immediately paint it..........

Long story short I think if you use the baking soda to hose down the walls it will eliminate the future issue.