epoxy problems

[Gino45]

I am hoping someone can give me some advice with my floor which is causing me grief. Let me start from the begining.
1- I thought that the previous owner had put some sort for sealer on the concrete floor, so I rented a grinder and grinded it off.

2- I bought a Amorpoxy kit and washed the floor with the cleaner/etcher that came with the kit.

3- Power washed the floor

4- Applied a primer

5- Applied the epoxy. Temp that day was 50 degrees (10c- for us Canadians)

6- The kit came with 5lbs of flakes, so I thought i should use up that amount on my floor- big mistake! I didn't spread the flakes evenly and hated the way the floor looked (my fault). I did not bother putting the clear coat on since I didn't like the look of the floor.

7- Mistake number 2- I orderd black, burgundy and white flakes. Well, when looking at a swatch up close the burgundy and black are easily distinguishable. But when looking from a distance- once on the floor- they look the same.

8- So I ordered more epoxy since I intend on doing the floor again. But tonight, as I was clean/scraping some loose flakes, I was able to use a utility knife and scrape off the epoxy coating- including the primer. Does this mean that the primer never stuck to the concrete? I noticed that the concrete left a powdery layer on my hand when I rubbed the floor once I had removed the epoxy. Can someone offer some advice on what I should do? Is it normal to be able to scrape off the epoxy with a knife? I had taken the day off tomorrow in order to put a new layer of epoxy, but now I fear that would be futile since the original epoxy coat isn't sticking. I had applied the original coat of epoxy two weeks ago.

 

[tc2000]

I noticed after my first attempt at acid etching, scrubbing and flushing, the dried floor still had a chalky residue in some spots, especially around the perimeter. So I took another pass with stronger acid and a stiffer brush and the resulting dried floor was like 100 grit sandpaper - no chalky residue.

 

[Gino45]

I had to grind down the floor. Afterwhich I acid washed the floor. Are you saying the I didn't rinse the floor sufficiently? If that's the case, what do I do now? I do not want to grind the epoxy off. Heck, I've already invested way too much time into this and too much money. I'm starting to think that a $50 dollar gallon of concrete paint would have been a lot easier and cheaper.

 

[tc2000]

No, I'm not saying that. I'm just suggesting it's a pain in the *** to prep these floors. I hope someone with more experience offers their expertise in the next few hours. I had read so many threads here my head was spinning by the time I just said enuf, I'm coating my floor. I do remember reading something about even after grinding the surface might not be prepared for epoxy until a proper acid prep. I think it was a recent thread, I'll try to bump it for you.

 

[LegacyIndustrial]

Gino baby, you either didn't neutralize the acid well enough or perhaps you have soft concrete...

Without seeing it's hard to say. Either way it sounds like your first go round was for practice. Now you will have to start from scratch and need to get that floor feeling like sandpaper 80 - 90 grit to be exact.

Don't feel bad, you are trying to master , in one shot, what took some of us many tries to perfect.

 

[Gino45]

Scott,

If I have soft concrete, what can I do? I do not want to pour a concrete floor. What I noticed it that I can peel the epoxy off the floor with a razor blade. It looks like the underside of the epoxy has a faint layer of the concrete floor attached. So it could be weak concrete, who knows. But I don't want to use up another kit for nothing, so are you recommending that I scrape the floor clean and start over?

 

[Hammerdown]

My $.02 - If you ground the floor already it should have removed any soft or powdery concrete, as well as the sealers. Did you test to see if the sealer was completely removed? A water test would have revealed this. You may have left powder inbedded in the concrete from grinding if the floor was not scrubbed thoroughly, or the acid wash could have left this residue as well after it dried out. Like Legacy indicated if the acid was not completey neutralized (by thoroughly rinsing away or even a baking soda wash) there could be remaining "hot spots" where the acid pooled and the coating was not able to bond properly. I would test other areas with some duct tape and a screwdriver. Lay out 4" strips of the tape in a few areas around the garage and leave it for 10-15 minutes. Take the srewdriver and rub it with a pressure on the coating. If it just scratches you should be fine, if it scrapes up the coating or pieces/chunks of the concrete, or if the pulled tape brings the coating with it you have an issue. Several tests if different areas will reveal if the problem is widespread or localized. If nothing comes up you may be able to repair the damaged area and have the coating perform as advertised, if multiple areas or large failures occur you should plan on removal to address the situation. Further grinding may be necessary to remove the coating and soft concrete surface down to a solid substrate. Or just use the floor as is, don't worry about it and see how it performs. If it keeps failing you have to remove it anyway, so today, next week or 5 years from now it would be the same procedures, so you may want to get some use out of it before you go back at it.

 

[Gino45]

Thank you for your advice. I am pretty sure that I removed all of the sealer as the floor was soaking up the water that I used to rinse off the etch solution. I'll try your tape and screwdriver test tomorrow. But for now, I had some epoxy left over from my initial application, so I patched the area that had lifted. I did not like the flake pattern that I used so I had already ordered some more epoxy, but did not want to "paint" over my first epoxy job since it did not adhere properly. I'll put on a top coat (clear coat) on Thursday (if it passes the tape test) and wait five days before parking my car in the garage. If it flakes off, then I will redo the floor next spring. Greg at Armorclad mentioned that I could use an industrial paint stripper to remove the epoxy, so that may be the route to take next spring. I want to avoid grinding the floor-way too much dust. Heck, I spent more time cleaning up the dust than actually grinding the floor.

 

[AlphaGarage]

Here's one scenario... When you etch the muriatic acid interacts with the calcium in the concrete, basically it causes the calcium to release from the concrete, but the calcium is still there - it's held in suspension in the acid/water solution. If that solution is allowed to dry the calcium settles back on the concrete, and sticks to it. The dust can be removed, but it's often easier to just do another acid etch, being sure to not let the solution dry.

If there was dust then when the primer was applied it may have adhered not to the concrete, but rather to the calcium dust.

If that's what happened, and the calcium dust was all over the floor, at this point you'll probably end up taking off the coating, by grinding, down to the concrete. Then redo the application starting with the primer.


BTW Usually there's no reason to acid etch if the grind went well. Also, you can have the same problem with dust from the grinding process, but that dust isn't sticking to the concrete so it's easy to vacuum or rinse off. The rental yard may have a vacuum that's designed to work with the grinder, if so rent it because they can do a real good job with the dust.

 

[Gino45]

The hand grinder that I used had an attachment to hook up a vacuum. I used my shopvac (5hp), but it seems that it couldn't handle all the dust that the grinder was kicking up. In addition, the filter would get clogged frequently. I am hoping that I can just use a paint stripper to get it off. For now, due to time constraints, I am willing to live with it. The patches that I did the other day of course don't match with the rest of the floor. They turned out more shiny. I am hoping the clearcoat will even out the shine.