Recoating poly?

[Miles B]

Hi

I have a 6000 sqft shop on which I put down white epoxy and 2 coats of poly. This has been sitting for 6 weeks. I am happy with the finish, but I have some flaws that I need to repair (popped bubbles and bugs). I also didn't use enough poly and have about 1/3 of it left over. That stuff is hard to judge on a white floor!

The tech sheet says to lightly sand. I am used to this concept from painting cars. My question is what sort of machine can I use for this? I have heard of people scuffing poly on wood floors with strips of PSA sandpaper stuck onto a floor polisher pad running at a few hunded rpm.

Any advice is greatly appreciated.

 

[Shea]

A floor maintainer with a 100 grit sanding screen works great. Just rough up the finish enough to degloss it and get through the tops of the bubbles.

 

[Miles B]

Thanks, I was not aware there was a screen available for that type of unit. I have some.. I guess.. raised crater edges around the larger bubbles. I was planning to hit those individually with an orbital. I imagine the screen will cut those flat.

I googled and they're pretty cheap. About 5 bucks a pop. Some of the sites say they can be used on concrete (though they don't last long). My friend saw my shop and wants to do his 2 car garage (new concrete) with my leftover epoxy. I was planning on acid etching, but could these do the job? Even if I burn through a whole box, that's cheap.

 

[LegacyIndustrial]

Acid etching is only viable on pure concrete no sealer, no coatings.

The sanding discs are great you will get action on both sides so make sure you flip them over when one side is shot.


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[Miles B]

Thanks. I didn't much like the idea of acid. I know it probably works just fine, but again I'm used to painting cars, and I've seen plenty of coating failures from people who didn't get all of the phosphoric or hydrochloric out of the metal. I'm a big fan of physical abrasion for preparation where possible.

 

[Armorpoxy]

We have found that a floor buffer with a 3M type pad white or red works well scuffing up an existing coating for adhesion. Wipe down with denatured alcohol and recoat.

 

[SunsetsAndFriends]

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[Miles B]

Sorry, the one I was looking at acid etching is bare concrete, laid about 6 months ago. Can I screen this or do I need to etch?

I am definitely going to 100 grit screen my shop, which has the fresh epoxy/poly on it but needs more poly.

 

[LegacyIndustrial]

The fresh concrete would need to be etched or ground. Screening this would be fruitless.


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[SunsetsAndFriends]

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[Miles B]

OK thanks guys, I'll use the acid on the new garage floor. It's tough to find and expensive to hire diamond machines over here. I had my shop done professionally, two grinds. Cost me 5 grand Australian, and that was comparatively cheap.