Epoxy Primer Not Curing

[Maverickcustomrods]

Over the last week I have been prepping my garage with grinding and cleaning. Well fall came this week and so did lower overnight temps. I decided to go forward and start the process of coating the floor with corotech v155 primer only to wake up to a still wet garage floor and regret that all my many hours getting it ground perfect were for nothing. About 80% is still left to dry, my question is what are my options as to cleaning up and waiting till spring to try again?

 

[oltruckag]

How cold did it get? Since the epoxy requires heat to cure (via chemical exothermic reaction between a&b parts) if it wasn't kept above the 55 deg min temperature and the concrete was that temp or below the epoxy won't cure unless you keep the space and surface heated above the min temp.

The instructions for the v155 say to use v704 for cleanup, but depending on the size of the area this may not be practical (and will likely be a huge mess). Your best option is probably to try and heat the space so the epoxy will cure enough where you can grind it back off. Even if it does appear to be cured I wouldn't trust it as a base coat for anything else. It would just be frustrating and expensive to put on a topcoat to have the whole system fail 6 months later because the primer fails due to incomplete cure.

 

[Maverickcustomrods]

Thanks for the reply. It was around 65 air temp when I applied and it dropped to 37 degrees when I drove in to work the following morning. I don’t know what the concrete temp ever was. It’s now been 38hrs and it is slightly tacky in places, semi gloss in others and doesn’t look like anything was applied in some areas. Current air temp in garage this morning was 51 and upper 30s outside.

I don’t have anything to measure the concrete temp.

What if I leave it and use it this winter and in spring grind again and start the process again?

The weather changes every time I look at it but it looks like Monday and Tuesday it will be back in the 70s and 50s overnight.

 

[Shea]

If it didn't get too cold and it warms back up during the day, then many times epoxy will continue with the curing process. Also, check the actual slab temp. In the fall, overnight temps can fall, but the slab stays warmer since the ground has not had a chance to get that cold. If that is the case, the epoxy should eventually cure as it should, but it takes longer.

After that, you should check the forecast to see what type of weather is coming up. You might have to wait before applying the rest of the flooring. Regardless, any subsequent coats are going to require that you degloss and rough up the primer coat first since you are past the recoat window.

 

[Shea]

Thanks for the reply. It was around 65 air temp when I applied and it dropped to 37 degrees when I drove in to work the following morning. I don’t know what the concrete temp ever was. It’s now been 38hrs and it is slightly tacky in places, semi gloss in others and doesn’t look like anything was applied in some areas. Current air temp in garage this morning was 51 and upper 30s outside.

I don’t have anything to measure the concrete temp.

What if I leave it and use it this winter and in spring grind again and start the process again?

The weather changes every time I look at it but it looks like Monday and Tuesday it will be back in the 70s and 50s overnight.

You posted just before I did. Yeah, those are cold temps. I would wait it out till it warms up and see if it finishes curing. If it does, you will be OK. However, if it remains tacky in areas, it will not improve and you will need to remove it.

 

[oltruckag]

If it was me - I'd heat the garage back to 65 and let the coating set. Don't waste time top-coating, but live with it until spring and regrind and start over. You may just decide to live with it as is - how does it look now?

Hindsight is always 20-20 and it ***** you put in the labor and the coating isn't curing. To avoid the temp drop over night you could have warmed the epoxy products to ~70/80 deg F and kept the garage above 55 and it probably would have cured correctly.

 

[Maverickcustomrods]

You posted just before I did. Yeah, those are cold temps. I would wait it out till it warms up and see if it finishes curing. If it does, you will be OK. However, if it remains tacky in areas, it will not improve and you will need to remove it.

I will be putting v410 and flake which has a lower curing temp of 35. Top coat will be v500 which requires a minimum of 50. Wish I was ready last week. Was in the 80s and 70s everyday...

 

[Maverickcustomrods]

I was able to find an infrared temp gun and the coldest reading I got was near the seal of the garage door and it read 52*, everywhere else it was 58 and 64 in one of the more sticky areas. It’s been almost 48 hrs.

I had the primer inside my house since I bought it and mixed it the 5 minutes with a paddle mixer on low speed per the directions, and let sit 35 minutes.

Would the temperature being on the edge of what’s acceptable really make it harden this slowly?

 

[Shea]

Would the temperature being on the edge of what’s acceptable really make it harden this slowly?

Yes.

 

[Jackal-44]

I’m curious what ever happened with the floor. Did it eventually cure, or was a regrind needed?

I applied my primer this morning and while it said 2 hours until dry to the touch, I’m still waiting on it. I started the Google search and found this thread. Now I’m getting anxious.

 

[Shea]

I’m curious what ever happened with the floor. Did it eventually cure, or was a regrind needed?

I applied my primer this morning and while it said 2 hours until dry to the touch, I’m still waiting on it. I started the Google search and found this thread. Now I’m getting anxious.

Two hours till dry doesn't sound right. Was an accelerator used or is it a fast cure epoxy?

 

[Jackal-44]

Fast cure epoxy primer Corotech V156. The can said 2 hours to touch dry, and 5 hours before recoat (72 hour max recoat without abrasion). I was hoping to start the first of the base coats last night, following up with the second and flake tonight. Now rain is in the forecast for tonight and I'll be pushing the start another day anyway.

I called my guy, and he said the can is unrealistic in the cure times. I left the heaters on in the garage to maintain a 24 degrees Celsius temp, and this morning the tack is almost all gone. I'll be keeping the temp up over night and hope to get the first base down tomorrow. I am so glad it seems it was just needing more time and not a regrind.

 

[Shea]

Fast cure epoxy primer Corotech V156. The can said 2 hours to touch dry, and 5 hours before recoat (72 hour max recoat without abrasion). I was hoping to start the first of the base coats last night, following up with the second and flake tonight. Now rain is in the forecast for tonight and I'll be pushing the start another day anyway.

I called my guy, and he said the can is unrealistic in the cure times. I left the heaters on in the garage to maintain a 24 degrees Celsius temp, and this morning the tack is almost all gone. I'll be keeping the temp up over night and hope to get the first base down tomorrow. I am so glad it seems it was just needing more time and not a regrind.

Remember, these cure times are based on optimal temperatures. This is usually around 75 degrees F or 23 C. The lower the temperature the longer the cure time and vice versa. Also, keep in mind that the surface temperature of the concrete and not the air will dominate.