Epoxy floor coat bubbles ??

[waltereo]

Hi,

I am painting my garage floor with epoxy coat and now I laying the first coat.
But I notice that after a couple minute after the coat is down small bubbles (1-2mm diameter) appear on the coat
The bubbles appear at the place where there a small holes on the concrete. It seems some gas or air are coming out of those holes ?!?!?!

My concrete is 30 years old, properly cleaned with etcher , water cleaned and now completely dry after 3-4 days.
The concrete is bare concrete No sealer or coat has been put on it since 30 years.


Is it normal, ? Did I do something wrong ? What should I do to fix those bubbles. ??


Thanks for advice !

 

[menz300]

This sometimes happens when working with 100 percent solid epoxies and it is out gassing bubbles or fish eyes. The easy fix for this is having a porcupine roller or a spiked roller to roll over the bubbles one time to let the gas out. Not sure what to do now that they are dried and you can see them....

 

[waltereo]

This sometimes happens when working with 100 percent solid epoxies and it is out gassing bubbles or fish eyes. The easy fix for this is having a porcupine roller or a spiked roller to roll over the bubbles one time to let the gas out. Not sure what to do now that they are dried and you can see them....

Well, it is not 100 solid epoxies. It is a 2 part epxy from Behr

2-Part Epoxy Garage Floor Coating


Thanks

 

[Floorguy]

What time of the day did you lay your epoxy? I have learned over the years that I put down primer (first coat) towards the evening time. This is when the slab starts to cool so it is absorbing thing. If you put it on while the slab is warming it tends to make those bubbles. Just my $.02

Once you have them it is a matter of jsut sanding them down with a palm sander.

I hope you are plannign on using flake. that will help cove them up.

 

[waltereo]

What time of the day did you lay your epoxy? I have learned over the years that I put down primer (first coat) towards the evening time. This is when the slab starts to cool so it is absorbing thing. If you put it on while the slab is warming it tends to make those bubbles. Just my $.02

Once you have them it is a matter of jsut sanding them down with a palm sander.

I hope you are plannign on using flake. that will help cove them up.

I laid the epoxy paint in the evening arounf 9h00PM. But I will try to pass the roller 5 -10 minutes after to flattening th small bubble.


But I still dont understand why bubbles appear ?

Thanks

 

[waltereo]

Update.

As I said I passed the roller after 5-10 min to flatening the bubble. I t workd great. As mentionned under the bubbles, there is a tiny home from the concrete, those holes are visible and the epoxy 2 part coat didn't convert them.

I am really convert about those tiny hole in my concrete because they make the epoxy 2 part coat useless since the water can go into the holes and build up humidy. I guess in the long term that humidity will mke the coat lift.
Just for information, my concrete in the garage is about 30 years old.

Anyone has a solution ??

 

[thegarageguy]

Bubbles means your slab is very pourus. The chemical is displacing the air in your slab and causing to trap the air within the epoxy, hence bubbles.

Like Menz said, spiny roller is the trick. You should have primed first, then lightly sand any imperfection. Then you would perpatch any pin holes and pour your body coat. You would of not had this isue.

 

[waltereo]

Bubbles means your slab is very pourus. The chemical is displacing the air in your slab and causing to trap the air within the epoxy, hence bubbles.

Like Menz said, spiny roller is the trick. You should have primed first, then lightly sand any imperfection. Then you would perpatch any pin holes and pour your body coat. You would of not had this isue.

What is a spiny roller ??

 

[AlphaGarage]

Also known as a "porcupine roller." It a roller, or roller cover, that has a bunch of small pins on it. Roll it over the surface (before the coating sets up) an it will pop all those bubbles.

Most available ones are metal, and cost around $100. There are less expensive plastic ones, but I don't have a source at hand.

 

[waltereo]

That's funny .... Anyway.. !

that's true the concrete is pretty poureux. The texture is almost almost like a road asphalt ...

Could I force those hole to be filled with the coat by using squeegee ?? that way no more air and bubble that will come up ??

What do you think ?

O it is better to gringe a little bit a put a resurfacing concrete over it to have a more smoother look ??

 

[Andy S]

Putting the epoxy thicker wont fix the out gassing. Use a water based epoxy for a primer, it will help a lot. If you still have bubbles after the first coat of 100%, sand them, fill with caulk, sand again, then put your top coat of 100% on when everything is dry.

Yes it is normal for that to happen, especially old concrete.

 

[Dave88LX]

Yikes, $100 for a spiny roller? I wonder if there is something local I can pick up in case I have this issue.

How common is this problem with this work? I guess I will wait until evening to lay my primer coat, after work, to have a better chance against it.

 

[FFPL]

try using a leaf blower. Worked for my neighbor.

 

[WolverineCoatings]

Bubbles form in the primer when you have alot of gassing coming from your concrete. There are MANY reasons that you can have gassing although the two main ones are either 1) coating in the morning when the concrete is going into it's warming/gassing phase or 2) no vapor barrier...

Solventbased and waterbased products are less likely to gas because the solvent or water evaporates during the curing. As the solvent and water evaporate they leave a microporous structure which allows the gas to escape. And, that's fine except that a microporous structure is weak! Its like the difference in hardwood floor that is solid and one that has about a million holes drilled in it. So, while you're less likely to get bubbles in the primer, you get a weak bond and floor.

So, the remedy to this is simply to break the bubbles with some mild sanding when the primer cures.

As you can see, using a primer is smart! Many floors will go down well without a primer... but... you never know when you should have used primer until it's too late! The smart move is to ALWAYS prime and do it in the late afternoon when the concrete is beginning to cool.

 

[roger55]

Putting the epoxy thicker wont fix the out gassing. Use a water based epoxy for a primer, it will help a lot. If you still have bubbles after the first coat of 100%, sand them, fill with caulk, sand again, then put your top coat of 100% on when everything is dry.

Yes it is normal for that to happen, especially old concrete.

Really, you can use water based epoxy as a primer for a 100% solids epoxy?
Wouldn't you have to worry about the compatibility of the 2 products?

 

[WolverineCoatings]

Using a waterbased epoxy as a primer for 100% solids is like putting scotch tape on your floor and then duct taping over it. The duct tape is strong... but... if the scotch tape comes up the duct tape comes up with it!

 

[waltereo]

WolverineCoatings,

Since the concrete is pourous, for the primer, should I pour a good amount 2 part expoxy coat, lay it down with a roller, let the concrete absorb the coat and then make the coat very thin as a first coat ???

My point is for the first coat, should I let the concrete absorb a maximum of coat ???


Thanks

Bubbles form in the primer when you have alot of gassing coming from your concrete. There are MANY reasons that you can have gassing although the two main ones are either 1) coating in the morning when the concrete is going into it's warming/gassing phase or 2) no vapor barrier...

Solventbased and waterbased products are less likely to gas because the solvent or water evaporates during the curing. As the solvent and water evaporate they leave a microporous structure which allows the gas to escape. And, that's fine except that a microporous structure is weak! Its like the difference in hardwood floor that is solid and one that has about a million holes drilled in it. So, while you're less likely to get bubbles in the primer, you get a weak bond and floor.

So, the remedy to this is simply to break the bubbles with some mild sanding when the primer cures.

As you can see, using a primer is smart! Many floors will go down well without a primer... but... you never know when you should have used primer until it's too late! The smart move is to ALWAYS prime and do it in the late afternoon when the concrete is beginning to cool.

 

[thegarageguy]

WolverineCoatings,

Since the concrete is pourous, for the primer, should I pour a good amount 2 part expoxy coat, lay it down with a roller, let the concrete absorb the coat and then make the coat very thin as a first coat ???

My point is for the first coat, should I let the concrete absorb a maximum of coat ???


Thanks

I know the question was directed to Wolverine but let me just say that all waterbased products are rolled on and have to be spread thin. If you go too thick it will have curing issues. I am sure he will have a more technical and detailed answer.

Roll on the water based primer. Next day lightly samnd down any imperfections, then base coat it.

 

[thegarageguy]

fill with caulk
QUOTE]

Not to knock you Andy, but this info is a bit misleading or not understandable. Are you suggesting to patch with caulk??? What type of caulk? I have never heard of such a thing.