Epoxy disaster! Any ideas?

[Peter_Frantz]

Here's the story. I just had a new detached garage built on a new concrete slab. After the slab was poured, I noticed little white fibers sticking up out of the concrete. After I etched the surface with muriatic acid, it seemed like there were even more fibers protruding from the surface. I'd say there were about 2 to 5 fibers every square inch, and they're about a half inch long. I thought they might be good and bad: They might help to anchor the epoxy to the floor, but they might also create bumps and spikes. I tested a small area by brushing on some epoxy, and they seemed to lie flat. So I figured it was probably OK to leave them.

It wasn't. I applied the epoxy yesterday. I guess the process of rolling the epoxy out caused the fibers to all stand up, and the epoxy made them hard. It looks good except for all the bumps, but it hurts to walk on with bare feet and it won't be comfortable on my back under my car. Like a bed of nails.

Its a 720 square foot garage. I used "Epoxy-Coat" 100% solids epoxy. I chose this because I wanted to do just one thick coat, and I laid enough for about 12 mils thickness. If I had used some cheaper stuff, I'd just rent a floor sander and then put down another coat, but I can't afford to buy another batch of the same stuff, and I don't want to risk having poor adhesion of some cheaper stuff on top of this.

I tried taking a sanding board with very little pressure to knock off the peaks. It helps to make the floor less sharp, but it does take some of the gloss off of the flat areas.

I'll call the "Epoxy Coat" folks tomorrow to see what they recommend, but I thought I'd check here to see if anyone had ideas, since there seems to be a lot of knowledge here. I'd sure appreciate any advice you have.

--Peter

 

[bmwpower]

Same problem here. My solution was to sand down the fibers AFTER coating the floor with a layer of epoxy. Worked like a charm. I put down multiple layers, so it wasn't a big deal.

I think your only solution at this point is to sand down the epoxy, just enough to remove the fibers, then coat the floor with another layer of epoxy.

 

[JCByrd24]

I agree with bmw on this one. A light sanding and they another thin coat of the same stuff would seem to be the best bet. Fortunately the concrete won't soak up nearly the same amount on the second coat so hopefully it won't break the bank.

 

[Peter_Frantz]

Thanks for your advice. You're both probably right. I'll probably have to do it. It's just that I've already got a really thick layer down, so I don't need another coat for mechanical strength. It'll be another $300 and 6 hours for primarily cosmetic work.

What about a light sanding to remove the bumps and fibers, and then a urethane topcoat with more flakes? In Floorguy's excellent thread on "the truth about epoxies", he mentioned a urethane topcoat as standard practice. Does anyone know if this would look OK over a lightly sanded epoxy (with flakes). And would it bond effectively and maybe promote longer wear resistance?

Thanks again,
Peter

 

[bmwpower]

Thanks for your advice. You're both probably right. I'll probably have to do it. It's just that I've already got a really thick layer down, so I don't need another coat for mechanical strength. It'll be another $300 and 6 hours for primarily cosmetic work.

What about a light sanding to remove the bumps and fibers, and then a urethane topcoat with more flakes? In Floorguy's excellent thread on "the truth about epoxies", he mentioned a urethane topcoat as standard practice. Does anyone know if this would look OK over a lightly sanded epoxy (with flakes). And would it bond effectively and maybe promote longer wear resistance?

Thanks again,
Peter

I bet you would never see it....especially with flakes.

 

[snorvet]

I have epoxy coat with a urethane topcoat since May, 2006. Looks good but the topcoat has yellowed a little where tires sit. A little sanding and a topcoat should solve your fiber problem, but I recommend calling epoxy-coat to see what they recommend for a topcoat.

 

[sjsfire]

Do yourself a favor and if you don't have a small $20 propane torch get one at your local hardware store. Get down on your knees and crawl around and melt them. Don't sit in one spot and get the paint hot.......just pass the torch over them, they should melt. See how that works before you try another coat. Somebody just asked the same question in the general garage forums.

 

[Hammerdown]

I have used the torch method after acid washing but before application of the epoxy. This method works the best. You may try burning the fibres now, but make sure to heed the movement of the torch. DO NOT stay in one place too long! The epoxy should clean up after the burn finish. You might try that method first. I would think to achieve the finish you desire, you should do the following-
Scuff sand the coating with 60-80 grit sand paper to create a mechanical profile.
Remove the debris.
Burn finish away any remaining fibres.
Apply additional coat of material.

It may cost more to add another coat, but you will be happier with the finished product.

Or.... Just think of those fibres as an anti-slip additive and live with it.

Just my .02 cents.

 

[z28toz06]

do you have any idea where the fibers came from or what they are? is it fiberglass in the cement for strength? it sounds strange.

 

[Peter_Frantz]

Thanks for the advice. This is really helping me to sort things out. I think I'll try burning the fibers in the corner where the workbench will go. But I think it's more likely that I'll have to sand it down. There are many fibers that are bent over and completely covered with epoxy. These are like little razors sticking up out of the surface, and I doubt that the torch will have any effect on these. I think they'll have to be sanded.

So I spoke with a representative from Epoxy-Coat, the manufacturer of the product I used. She was not a big help. She essentially recommended sanding it down and applying another coat, but she did not believe that one standard kit would be sufficient to cover the whole floor. So I'd have to buy a kit and a half, which is close to $500. I think it's just too much for what is essentially a cosmetic defect (after I sand it), but I haven't ruled it out.

Barring that, here are my two other options:
1. Sand it down and recoat it with a cheaper product. For example, I could go with the solvent-based version of the Rust-Oleum product. The Epoxy-Coat rep refused to comment on how securely attached this would be, but she said that it would probably adhere better to the sanded epoxy than it would to the base concrete.
2. I could sand it down, and then apply one topcoat of Urethane (with new paint flecks), and then a second topcoat of urethane. The Epoxy-Coat rep said I'd probably have to sand it and recoat where the car tires ride after a couple years, but this would probably work.

So what do you think? Does anyone know if Rust-Oleum would be at least as good over a fresh sanded epoxy surface as it is on concrete? Is urethane a better surface?

Thanks again for all your help!
--Peter

 

[Peter_Frantz]

Hi z29toz06,

Yes, the fibers were built into the matrix of the concrete as it was poured. I assumed it was put there to increase the structural integrity, but I don't know. I also don't know what they're made of, but they're certainly synthetic and could be fiberglass I guess. Now that I'm researching it (which I should have done a week ago), I'm finding many people with the same kind of material in their concrete.

--Peter

 

[RickP330]

Hello,
Look, if the epoxy minus the fibers is Okay then I'd say just sand it down and put a clear coat urethane over it like Floorguys post reccomends. You would have to sand it to get the top coat to adhear at this point now anyway now that it is cured. I don't think it's a big deal, just more work. I wouldn't fool with more flakes, then you would definatly need another top coat over that.
Regards,
Rick

 

[Floorguy]

I guess my list of optioins would be:
Option 1

100 or 120 grit sand and apply a coat of urethane. The problem is finding a compatible urethane for your system. I would ask to speak with a engineer in the company if possible. This should fill in the scratch marks from sanding nicely and give you a better looking longer lasting floor.

Option 2.

Sand as above and put down another coat. This will certainly be compatible with you existing coating.

Option 3

Try the torch thing and see what you get. That is a new one on my so I can't speak to how well it works. I would like to get some feedback on that if it does work for you.

Sorry that I can't be more help. I have never seen this before so I can't speak from experience on this one. The style of floor that I do this would not be a problem as they would all be covered with flake, then epoxy again, then urethane.

Let us know what you do and how it turns out.

Don

 

[mdshore348]

its def fiberglass reinforcing additive, they wont burn , just knock them down with a sanding .