Polyurea prep Guidance

[Mattbee]

Hey everyone, long time viewer here. I’m getting ready to start work on my shop floor here soon, but had some questions about prepping it.
My plans for the shop floor are to grind it, stain it and then put a Polyurea clear over it (I was looking at armorpoxys Polyurea clear)
Some background on the shop: The main floor in the shop was poured in 1963. I replaced the first 13ft of it in the summer time. The concrete isn’t in bad shape besides the cracks. It’s 6” thick and over 12” through the center of the shop (hence the crack that runs across the building). I’m going for a vintage look for the shop, so I don’t mind seeing the cracks, I’d just like them to be smooth
What should I fill the cracks with? There are some divets in the floor from something being bolted down too
What grit stone should I get for the grinder?
Is there a certain stain I should use? Thanks guys! Here’s some pictures of the shop.

 

[Shea]

I would recommend using a water-based stain. An acid stain will not work well if grinding. Acid stains work by reacting with the free lime and minerals on the concrete surface. When you grind, the process removes most of these minerals at the surface for the acid to react with. As a result, the concrete does not take the stain well.

I would suggest filling the cracks with a colored crack repair filler unless you want the cracks to stand out with a gray color. The proper repair material required to fill and repair cracks (polyurea or epoxy) will not take a stain. Legacy Industrial has a great product called Xtreme Set 100 that comes in a few different natural colors.

 

[LegacyIndustrial]

 

[Imatk]

The way I did it was to rend the grinder from Home Depot, it was a single-head so it took a bit longer, but it worked great.

After the grind I cleared out all of the dust, and then I filled the cracks with some concrete filler, again from Home Depot.

Once that set, I just used my hand grinder and smoothed out all of the filled sections and then I was ready to go.

This is the filler I used:

https://www.homedepot.com/p/Quikrete-1-Qt-Concrete-Crack-Sealant-864000/100318507

 

[Armorpoxy]

Hi, our SPGX one part Polyurea which you mentioned works great with water based stains. A light grind or etch is all that is necessary. If you are grinding, you want to use or stop at minimum #120, otherwise you may see swirl marks, especially with clears which tend to magnify grinding marks.

We carry a clear crack filler that you can mix in the grinder dust so it matches the floor color. Alternately, Metzger & Mcquire sells their RS-88 Polyurea crack filler in about 100 colors and is available online.

Best to contact us directly at below for individual support on your project, not PM please. Thanks!