Need some urethane experts (issues on a floor with a picture).

[workhurts]

So, long story short I decided to dive into the deep end with my floor. I wanted metallics so that's what I did. All went reasonably well, and I was in the home stretch till my urethane (or polyurethane) dried.

I was left with thousands of tiny pinhead sized dots. My upplier is looking into this but figured your collective wisdom might also help.

So, how do I fix this? Chances are sand/screen to knock all these down and urethane again. I want to make sure I don't experience the same problem again and that doing this won't make the floor look worse. You can only see the issue when staring at the reflection from a light source as you can see in the picture (the dots and light reflection cover a couple of inches in the picture but they are all over the floor).

Kept garage doors open as recommended to keep air flow up. Temps were in the upper 70s. The prior coats were primer, base, metallics, clear epoxy ... and then urethane.

I've read everything that suggests maybe 3/8ths nap is too long to maybe I was backrolling too much and introduced air or the coat went on too thick or contaimates flew in or dropped off the ceiling. The stuff doesn't feel like a contaminate but who knows. I've even heard that it might just correct itself with use since the urethane is kinda rubbery.

Ideas welcome. At this point I'd like to just fix it while trying to understand it a little so I don't have the same issue.

 

[Shea]

A couple things come to mind - Did you use a 1-part moisture cure urethane or a 2-part aliphatic urethane? And, how high was the humidity? Moisture can hinder the cure of polyurethanes, especial 1-part moisture cured urethanes. The moisture in the air can cause a reaction that will produce carbon dioxide gas within the mix, thus causing all the pinhole bubbles. 2-part polys are more resistant to this due to the solvents used as a carrier agent, but it can happen on occasion.

I prefer a 1/4 nap roller vs a 3/8 nap for polyurethanes, but the difference shouldn't cause your problem. Also if using a 2-part, were you mixing at low speeds? I've seen this from mixing too fast and introducing air to the mix as well.

So, how do I fix this? Chances are sand/screen to knock all these down and urethane again.

Yes, that is your best bet. Your base coat of metallic looks awesome by the way

 

[LegacyIndustrial]

It is easy to contaminate a surface, dust, open window, sketchy rollers, etc...
Even in the best of conditions surface issues can happen. Obviously, they look worse on such a good looking, glossy floor.

 

[workhurts]

How on earth do you keep contaminates out when you have to keep the doors open? I actually put mesh netting across the doors but that's only going to keep out grass blades and bugs. Maybe I need to wipe down all the walls, garage door rails and whatever elsed I can get my hands on. Maybe I can setup a semi-conducter fabrication shop in my garage while I'm at it.

As for the type, it was a two part and definitely lots of solvents. The whole neighborhood could smell it (I had a respirator on).

Humidity, not sure but looking at the forecast before I began on weather.com it had it pegged at around 60%. It's not going to get lower than that in the DC area. At night it's around 100% but I put this stuff down at around 1pm.

What is the best locally sourced roller cover for a 2 part poly? I even did the whole tape thing on the roller. Was thinking maybe an ulta dense foam one would do better?

Since these things are so small and urethane is so thing, how would I know I've sanded enough? I don't want to sand too much and created grooves that the new urethane can't fill. Recommend 100 grit or something closer to 200?

 

[workhurts]

Oh, one other thing. How on earth do I tell the difference between a contaimant or not with these things. They look clear and I can't see anything under them that doesn't look like it should be under them.

Should I be rolling the floor with a giant sticky roller (like you use to remove pet hair from clothes and stuff)?

 

[bigbadktm]

It's trapped air. Sand with a 200 grit screen, solvent wipe and reapply. They do make pads for applying urethanes and I have heard people have good luck with them, but I just use a 9" 1/4 nap roller cover, or if it's a large smooth floor,I will go with an 18".

 

[sxk122]

I have no usefull input other than I want to see a wide angle shot of the floor. From the closeup, bubbles or not, that looks awesome!!!!

 

[JakeKohl]

I have no usefull input other than I want to see a wide angle shot of the floor. From the closeup, bubbles or not, that looks awesome!!!!

indeed!

 

[bigbadktm]

missed the part about the 3/8"...you went too thick. Sometimes the metallics will bubble due to the thickness that it goes down...see a lot of that

 

[pauloman]

shea is right - 1 part low solvents generate bubbles - especially in thick coatings. It has been a problem for low solvent poly manufacturers for years. The quest for a solvent free poly has been derailed over this issue.

The lesson is not to deal with vendors that don't know, or will not tell you, what can go wrong.

 

[workhurts]

bigbadktm - the metallics aren't bubbling. The primer is fine, metallics base is fine, clear epoxy over base is fine. Just the urethane is the issue right now.

pauloman - it wasn't a one part low solvents urethane. It's a two component polyester/aliphatic polyurethane.

I do agree, perhaps 3/8th is too long and it went on too thick but I was pretty careful with the coverage guidelines. My uneducated personal opinion is that I backrolled too much and introduced air or the product is just super sensitive to something. Maybe my clear epoxy hadn't completely cured but it was a 100% solids and I gave it 20 hours and was tack free.

I'll post pictures as soon as I tidy up