Another oil question...

[Trek7700]

I'm prepping my 1,000' garage floor for epoxy and I have a few oil spots that are big and old. I degreased using an industrial emulsifier and a scrubbing machine which did wonders for the majority of the floor but not on the big oil stains.

I rented a floor grinder but that didn't do much on the big stains but I found that if I use full strength acid, it takes away the remaining oil. I verify by heating with a torch and there is no more oil bubbling.

My question is...is it harmful to etch the whole floor with 100% acid? I did a 75% mix before and I don't have a good etch on the entire floor (the concrete was smoothed when it was finished) so I need to do it again anyway.

Out of all the methods I tried, soaking in etching was the fastest way to get rid of the oil but I don't want to compromise the concrete...thanks

 

[Shea]

My question is...is it harmful to etch the whole floor with 100% acid?

Yes. The only reason it helped with your large oil spot is that the 100% acid degraded so much of the surface that it took the concrete with the oil stains with it. Acid does not break down oil. It reacts with the free lime in the concrete, breaking it down and opening up the pores. If you do the entire floor in 100% acid you will severely weaken the top surface of your concrete.

 

[IOWNJUNK]

Cleaned my carport with muriatic acid once. All that was left when the smoke cleared was gravel.

 

[James-W]

Cleaned my carport with muriatic acid once. All that was left when the smoke cleared was gravel.

Reading that made me laugh. I don't mean to laugh at your misfortune, it just sounded funny.

 

[IOWNJUNK]

Reading that made me laugh. I don't mean to laugh at your misfortune, it just sounded funny.

I laugh about it now, but it wasn't funny at the time. I even tried a small spot with it first, dribbled it on then scrubbed with a broom and rinsed with a hose. It worked pretty good. And well, more is better, right? So I dumped a whole gallon of it on an oil spot (about 1'x4'). It smoked and foamed up, I thought "man, this stuff works great". About 30 minutes later I hit it with a hose and noticed all that was left of the oil spot was loose gravel.

Live and learn I guess.

 

[jaye944]

As Shea says yes DO NOT use 100% the lowest safe is 5:1

pls look at my links, you NEED to get as much oil out as possible,

BEFORE you grind.

The oil is trapped in the concrete like a sponge, so you need to draw it out (as discussed in my links)

IF you are still stuck you can use an EPOXY OIL primer which will cover it and stop it bubbling to the surface, Armourcoat do one.

It is BLACK, but it is over paintable

I'm prepping my 1,000' garage floor for epoxy and I have a few oil spots that are big and old. I degreased using an industrial emulsifier and a scrubbing machine which did wonders for the majority of the floor but not on the big oil stains.

I rented a floor grinder but that didn't do much on the big stains but I found that if I use full strength acid, it takes away the remaining oil. I verify by heating with a torch and there is no more oil bubbling.

My question is...is it harmful to etch the whole floor with 100% acid? I did a 75% mix before and I don't have a good etch on the entire floor (the concrete was smoothed when it was finished) so I need to do it again anyway.

Out of all the methods I tried, soaking in etching was the fastest way to get rid of the oil but I don't want to compromise the concrete...thanks

 

[jaye944]

One other thing, what ever cleaning your doing on the surface is useless, the oil is BELOW the surface,

try a few tests

* does it feel oily to the touch (yes its on the surface)
* does it bead water (yes its on the surface)
* wipe it with xylene does it make the cloth dirty (yes its on the surface)