Shot blasting concrete floor before epoxy?

[BBC71Nova]

Any of you guys tried shot blasting your concrete floors before applying an epoxy coat? I've had good luck with acid etching in the past before applying a quality epoxy but I'm considering the blasting approach this time. It seems that it would provide an even better surface for adhesion. Not to mention I get to rent yet another piece of equipment .

John

[monza]

I've done in a warehouse floor and I was disappointed with the results. Maybe it was because I went a bit cheap on the epoxy coating we applied but it looks like ****. In my garage I did acid etching and high end epoxy it worked killer.

The best IMO concrete finishing is polishing it. Have to hire someone to do it and basically it gets ground multiple times to a super fine smooth finish, almost like a granite type surface. Becomes very stain resistant looks good and low maintenance. Can be very expensive and gets more expensive the more you grind, the more you grind the better the finish. You see it in high traffic areas, large grocery stores, universities etc. Check it out. googled this quick for you http://www.concretenetwork.com/concrete/polishing/

[rwhite692]

If you go over to www.garagejournal.com and do a search on epoxy floor preparation, you will have enough reading material to make your head spin...lots of discussion on shot-blasting, acid etching, etc.

[XcYZ]

I'll be doing the same in a few weeks. I'm working on getting the sheet rock finished up.

Post up some pics when you get started. What color are you going to go with?

[BBC71Nova]

Yeah, garagejournal is a good place for info. Actually that is where I first heard of shotblasting as an option a couple years back.

I called around locally to try and locate a shot blaster or diamond grinder/surfacer to use. The only thing I could find was a small 8-10" scarifier which seemed a little questionable to me. The wheel moved vertically instead of horizontally and I was afraid that would lead to visible grooves in the finished floor. Soooo, I'll do what I've done before and just acid etch it real good. This floor is new construction so there was zero oil, mud, etc on the floor fortunately.

I'm going to use the Sherwin Williams ArmorSeal 1000HS epoxy. It comes in a gray color or you can tint it. I've seen good reviews on it. It is similar to a product I used from Lowes a few years ago that was classified as an "Industrial Floor Coating" from the same company that has those Garage Kits. The industrial was not a water based epoxy though. They don't seem to sell it any longer so that is why I went looking for something else.

John

[Fluid Power]

I have experience with both ways. A buddy had his shot blasted by a commercial flooring company. It was an old garage that had previously been painted with floor paint. It did an amazing job. The paint was then applied per the directions on the can. It was a Sherwin Williams product and it looks fabulous. I had a garage floor that was in really good shape and tried acid etching. As it turns out, the previous owner had sealed the floor using Thompson's water seal. I went to an equipment rental store and rented a concrete floor sander that has two counter rotating discs on the bottom. It has diamond blocks on the discs. It makes one heck of a mess but it removed the water seal. The results after coating the floor were very good. If I had to do it over again, I would go the shot blast route. It was way less messy and wasn't that much more money than running around town renting tools and buying the diamond blocks.

Darren

[elitecustombody]

Originally Posted by BBC71Nova

Yeah, garagejournal is a good place for info. Actually that is where I first heard of shotblasting as an option a couple years back.

I called around locally to try and locate a shot blaster or diamond grinder/surfacer to use. The only thing I could find was a small 8-10" scarifier which seemed a little questionable to me. The wheel moved vertically instead of horizontally and I was afraid that would lead to visible grooves in the finished floor. Soooo, I'll do what I've done before and just acid etch it real good. This floor is new construction so there was zero oil, mud, etc on the floor fortunately.

I'm going to use the Sherwin Williams ArmorSeal 1000HS epoxy. It comes in a gray color or you can tint it. I've seen good reviews on it. It is similar to a product I used from Lowes a few years ago that was classified as an "Industrial Floor Coating" from the same company that has those Garage Kits. The industrial was not a water based epoxy though. They don't seem to sell it any longer so that is why I went looking for something else.

John

John, so how did that SW stuff worked out? I have bought a 5 gal bucket of that stuff with hardener and anti-slip flakes,wondering how you like it and how hard/easy it was to apply?

[BBC71Nova]

The SW product worked out great. I did my parent's new garage and a friend of mine did his new garage at the same time. Both turned out well.

It isn't exactly cheap at about 80$ a gallon but you get what you pay for . It is a 2 part product and each "kit" consists of 1 gallon of part A and part B so a "kit" is 160$ for the 2 gallons. The kit does not include flakes or a clear cost but both could be purchased if you want. I just like not having the flakes. Makes finding that little washer I drop a little easier .

I felt the coverage rate was much better than I had expected. I had planned on using 3 kits to do 2 coats for the garage that is roughly 24ft X 34ft. The second coat is optional but I did that on my basement and it makes all the difference. Any paint will soak into the concrete inconsistently due to the varying surface texture of the concrete. The second coat leaves a very uniform coating and well worth the time. I ended up only needing a little over 1 kit(~2.4 gallons) to do the first coat. The remainder of the second kit (~1.6 gallons) was just enough to do the second coat 24hrs later.

The last 2 floors I've done I used a high solids epoxy such as this and they have held up very well. Probably should add they were both new concrete. It really is all in the prep though. I swept good, and scrubbed with a good degreaser and rinsed 2 times. I then etched it with a ~4:1 mixture of water and muratic acid. I was prepped to go to the moon with rubber boots, thick rubber gloves, goggles and appropriate respirator. I would pour some of the mixture on the floor and scrub it in with a deck brush. Let it set for 10min or so and rinse off. I then performed that same process again. Then rinsed the floor a few times really well. Let it dry for couple days or so. I applied the epoxy starting at daybreak because I wanted the sun to be up so the bugs wouldn't come to the light in the garage and get in the paint. It is also much cooler in the mornings . Just check the humidity per the directions.

I'll be there this week and will snap some pics.

John

[hifi875]

so if you have a floor that has been clear coated, what it the best route to go if you want to epoxy the floor. i helped my father in law do his, we used muratic acid and i about died, it ruined my shoes and was hard to breathe. i don't really want to do it again that way.

[BBC71Nova]

Originally Posted by hifi875

so if you have a floor that has been clear coated, what it the best route to go if you want to epoxy the floor. i helped my father in law do his, we used muratic acid and i about died, it ruined my shoes and was hard to breathe. i don't really want to do it again that way.

From what i've read, your best bet might be to rent a shot blaster or floor surfacer to remove the old paint. Local rental places here were no help but you might have better luck. As mentioned, Garage Journal site has lots of info on this subject. I'd check there for other opinions. I just know that if you don't get the existing surface coating off there will be problems .

John