One section of clear not fully cured

[commok]

I did a 1350sf Epoxy Coat floor about three weeks ago (this was the second time I have used EC for a garage floor - my previous 2car garage floor has held up great over two years - we love it). For the latest project, I used 2 and 1/2 kits, followed the normal routine of one day prep of the new concrete that had cured for 3months with no traffic... Following day color coat, next day clear. The color coat hardened perfectly. The clear coat was applied 18hrs later, including the supplied non-skid. As with the color coat, I broke the applications up into roughly 10'x10' sections. My problem is the second to last section applied has still not hardened completely - all other sections are fine.... The one section in question is not tacky, I can walk on it without leaving an impression, and in general it feels like the other sections, however I can also take my thumbnail and scrape up small sections of the clear coat up. The color coat on that section is rock hard underneath. Its been three weeks, and I do not see any additional progress in hardening of this 10'x12' area. All other sections are fine - love it. Pictures attached.

Talking with Christine, she suggested I sand the section with 120grit and apply another coat of clear coat (I have enough left over from the project to do a 10x12 section again).

Questions:

Is there a chance the faulty section will harden up in a few more weeks?

Agree that the next best option is to apply a new clear coat on top of the sanded old clear coat?

Will the new clear coat have a positive hardening effect on the first clear coat?

Will the new clear, if hardened correctly, resist lifting and pulling up like it is supposed to?

Any other suggestions?

 

[SunsetsAndFriends]

I see your floor is divided up into sections by the cut joints. Is the faulty area all within one of the "squares" created by the cut joints?

I'm not a pro at epoxy type floors.

I would use a small putty knife to figure out the full perimeter of the soft area. I then would see if it just comes up with the putty knife or something flat and hard. Since you'll have to sand it anyway, I would suggest being aggressive with it. I would get up whatever is soft. Then I would sand it or power screen the area. Then I would wipe with the appropriate solvent to clean the dust off/pre soften the coating. Christine at Epoxy-Coat can tell you what to use. Some say MEK. Others have said alcohol. I would just confirm with Christine. Then apply another coat of clear to the area. In the end, depending on how it looks, you might want to screen the whole floor, wipe, and then do a full second coat of clear.

Some pros will undoubtedly chime in with their more experienced perspective.

 

[commok]

Thank you DIMT. Yes, the section is within the cut lines in the far left. It's the whole section...

 

[48RON54]

Man, I gotta say if something absolutely had to go wrong, you sure got the best possible outcome of wrong there could be. One section within the cut lines...man I'm kind of impressed at this point. Hope you get it figured out anyway.

 

[SunsetsAndFriends]

Since it's within the cut lines, it should be easy to fix if you get the prep right.


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[LegacyIndustrial]

Scraper, xylene and rags.
It all has to go. Not a fun job.

Once you have it cleaned up, scuff it good, wipe with denatured alcohol and coat again.

Breaking kits down to this extent is a gamble if you don't do it all the time.


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[kwfloors]

Yes, I say it was in the mix of not being right. Some products can be split into even cans, others can't.

 

[SunsetsAndFriends]

Seems to me that mixing/applying batches of the colored base coat is supposed to make leveling and then chipping floor easier for a newb/DIY'er. But with clear, probably better to mix in full sizes and apply it to the square footage needed to get coverage rates. Fewer batches means less chance for error. I read quite a few posts on forums related to mixing errors.


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[kwfloors]

The color base has pigments in it that will settle in the can to the bottom. Important to mix that thoroughly so mixing the clear should be a good thing also.

 

[LegacyIndustrial]

KW nailed it. Good idea to full mix the A & B, independently before you split kits. This is for clear and pigmented.

 

[SunsetsAndFriends]

KW nailed it. Good idea to full mix the A & B, independently before you split kits. This is for clear and pigmented.

Everything that I have read about any of the two part systems is that this is a basic step. Combine the the A together in a bucket from all the individual gallon containers. Mix to get a uniform color. And to take a step further, when mixing smaller batches, prior to every batch the A part and the B part should be mixed independently prior to combining and mixing. Settling occurs. I am no pro here, just what I've been reading.

 

[commok]

An update - it has been approx 3 months since application and the clear on this one has finally fully cured (I have been on travel for the last month, so it may have done so after 2months). Rock hard, no tacky or soft spots, and indistinguishable from the other sections of the floor. Pretty happy with the results - just wish this section had not taken so long to cure. I had made plans to sand this one section and apply another top coat of clear, but am glad I held off. I noted Christine had stated in a previous post (and told me on the phone when I called for advice) that in her experience any epoxy that had progressed past the tacky stage would eventually harden up completely. She is certainly right in this case.