Floor prep, clean and acid etch questions

[elmariachi]

I have worked my &^$$ off trying to get all the little oil spots up from the prior owner's leaky car. The oil is all gone, but there are a number of silver dollar-sized light tan spots where the oil once soaked in. And I still have a few tire marks that simply will not come up either. I have used TSP, Simple Green, paint thinner, 2700 psi pressure washer and contemplated a small nuclear explosion...nothing is working. I have sample tested my acid etch right over both the old oil spots and tire marks and it looks great, just like 100 grit sandpaper. What am I to do with these residual problem areas? If I have worked them over with every conceivable potion, and I okay to proceed after pressuring washing away the etch residue, or do I need to keep trying to get the spots up? FWIW, water does not stand on any of these, it soaks in.

Thanks.

 

['the epoxy floor guy']

Epoxies will attach to the surface of the floor using TWO types of 'bond' ONE is called MECHANICAL bond. This is bond is like using a screw into a board the SHAPE of the two pieces makes 'bond' together. When you acid etch, the acid eats away the tiny particles of lime and other chemicals in the concrete. This creates voids in the floor. When you apply the liquid epoxy the low viscosity epoxy will 'soak' down into the pores of the concrete and harden. When the tire comes over the floor and 'pulls' on the surface it has lots of tiny 'anchors' into the concrete to keep it down.

The other is called CHEMICAL bond. This is like Glue. A surface is attached to the glue by it's 'stickiness'. The degreaser you used removed the slight film of 'oil' so that the chemical bond between the epoxy and the concrete can happen.

If you applied your acid solution and got a slightly yellow fiz from the solution, you are probably ok.

If you have a Power sander (DA sander or Orbital) going over the tire areas ONE LAST TIME with a VERY COARSE 35 grit sand paper would NOT be a Bad Idea. Also if you have what I call a Float Stone. These are a handle attached to an abrasive stone usually used to shape stone or brick (you can purchase these at the box stores for less than $10). Using it to 'roughen' up the surface will help. 99% of the time if you have an adhesion problem it is in the tire track area.

You CANNOT over prep.

The more 'anchors' you have in the concrete the longer it will last.

 

[elmariachi]

Epoxies will attach to the surface of the floor using TWO types of 'bond' ONE is called MECHANICAL bond. This is bond is like using a screw into a board the SHAPE of the two pieces makes 'bond' together.

If you applied your acid solution and got a slightly yellow fiz from the solution, you are probably ok.

Using 50/50 from 30% muriatic pool acid I did gets lots of yellow fizz, and after 20 minutes I hit it with baking soda to neutralize and then hosed it off. What is left is a nice tan concrete with an 80-100 grit feel. The rest of the floor is still white and chalky but the area where I tested the acid looks primo for epoxy. I know I need to pressure wash it again afterwards to get all the residue off.

I tried the 35 grit with the Clarke floor sander before the acid and it didn't do squat (other than costing me $75 in wasted rentals and consumables and two trips to HD.) I have tested a bit more with the acid etching tonight and it is working great, even where I have been unable to get the tire tracks and oil spots up. So as far as mechanical bond is concerned I think I would be okay. But I am still a little paranoid after everything I have read here.

 

[megavettes]

I know how you feel. I just refinished a 30-year old concrete floor that had been originally sealed with an aircraft-hanger type sealer. The oil changes, paint and varnish from refinishing furniture, and tire marks were all there and ground in. I used an Edco floor grinder with diamond cutters to remove enough of the concrete surface to know it was "clean". I still had light stains and discoloration on the floor but since water didn't bead on them I considered it good to go. One caution, the Edco grinder puts out so much dust that everything will be covered. Make sure you use a good quality face mask and change the filters often. This is a must!

I used a fairly strong mixture of muriatic acid and soaked the floor twice. After that I pressure washed it and it was good to go. I was afraid of hot-tire pickup but after 6 weeks all is fine. I used a really great product called UCoat-It. Their support group is one of the best I've ever dealt with. I used their vinyl chips and clear AF sealer and would do it again. To make sure the floor is properly covered I plan on adding a second coat of clear sealer next spring. If you decide to use any product, just make sure to follow the directions to the letter. It should come out fine and you'll love it!!!

 

[ThumbsUp]

I had a similar problem with some old oil stains. I tried everything and nothing seemed to work; the stain was deep in the concrete.

One day I needed to paint some shelving where some oil had leaked onto the wood. I found a gallon of some stuff I had bought several years ago, but never used. As I recall, it was made by "Bond-Tite" and was called something like "Liquid Surface Prep". At any rate, it was designed to prep surfaces for painting without sanding. It cleaned the oil off the wood shelving immediately. I painted a few minutes later, and to my surprise, the paint laid down just as it would on fresh lumber.

Remembering those old oil stains, and knowing I had nothing to loose, I poured some of the Bond-Tite on the worst stain, waited about 30 seconds, and wiped off the excess. WOW! The white rag I was using turned brown with the crud it picked up. I continued with 4 or 5 more applications, letting the solvent soak in a bit each time. I continued until I could not see any residue being picked up on the rags. I let it sit a day or two and then did the water test, which soaked in immediately.

The label on the Bond-Tite lists the ingredients as Acetone, Naptha, Isopropyl alcohol, and some other stuff. In other words, there's something in there for whatever you've got!

 

[WolverineCoatings]

Hi All,

There is some truth in just about every post in here. However, 'some truth' means some... 'NOT truth'...

First,

Bonding of Epoxy to Concrete:

VERY VERY VERY few epoxies chemically bond to concrete... Almost all epoxies will simply form the mechanical bond that has already been referred to.

Degreasers:
A GOOD degreaser will attach to the oil and bring it to the surface so it can be wiped up or washed away. It DOES NOT magically dispose of the oil for you! So, if you use a degreaser and don't wash it away well enough the oil will simply redeposit after the water evaporates. Most degreasers are minimally effective under the surface of the concrete. There are many types of degreasers that work by many different mechanisms. How well a degreaser works depends on the type of oil (either synthetic or fatty acid) and the exact mechanism of the degreaser. We have about 10 different degreasers that work in various ways and then... various concentrations of those formulations. It is very difficult to simply classify all degreasers as the same.

Using Organic Solvents:
Using organic solvents like Lacquer Thinners can work in many instances. The thinner simply thins the oil and makes it more mobile. Then, one of 2 things happens... you either soak up the thinned oil with rags or the thinned oil pushes it's way further into the concrete UNTIL the organic solvent evaporates or combines with moisture vapor. THEN, the oil will begin to push it's way back up. Whether this approach will work for you or not depends on how much oil you have, the porosity of your concrete, the amount of sludge in the trapped oil, the vapor pressure under the concrete, and whether you are using a chemical resistant primer that will cure slow enough for the organic vapors to escape and fast enough that it will develop chemical resistance before the oil returns to the curing film. In general (probably should have put that in caps), this will typically work with small oil stains. Please keep in mind my perspective when I say small oil stains. Our products are being used every week on oil SATURATED floors. This past week a contractor did 80,000 ft2 where there was so much oil used that it was even in the air and dripped from the ceilings during the coating process. SO, I would consider just about any garage oil stain small.

OilEating Microbes:
Our oil eating microbes are living organisms that eat oil and excrete carbon diaoxide and water (in minute amounts). So, they eat the stuff you don't want and excrete natural stuff into the air that is already there anyway! In addition, since these little wonders of microbiology are so small they penetrate into the concrete, eat the deep oil, and excrete CO2 which easily escape the surface of the concrete.

SO... holy smokes that's alot to write...

If you're not concerned about money and want to make sure then go straight for the microbes. If the budget is more of an issue the go for the degreaser, organic solvent, or even a combination of both.

LAST, our BondTite 1101 IS chemically modified to chemically bond to inorganic surfaces like concrete. In addition, it is fluoropolymer modified with an extremely low surface tension that forces it to wick into the concrete and allows it to displace fluid oil. Last, it is modified so that it is NOT sensitive to moisture. If you think about the process of getting rid of oil it doesn't take long to figure out why all of these traits are so important.

OK, I've skimmed the surface on alot of different areas... but... I'm tired now... If anyone has any questions about what I've written the best way to get them answered is to ask Fred (AlphaGarage) since I'm only in here sporadically right now. Or, you can just post and hope I see it someday... lol...

Good Luck with your floors all...

 

['the epoxy floor guy']

I stand corrected, Wolverine is Right. MOST may NOT use a chemical bond.

But my product with the 'bond' additive DOES make a chemical bond. It will stick to GLASS, Porcelain, Even SOME plastics. Which would be a chemical bond.

That is why we have GREAT success installing our coatings with LESS concern of prep being 100% perfect.



adding an $8 additive can save a TON of work / GRIEF!