Failed grind?

[streetdaddy]

I'm getting ready to apply the norh- S coating pretty soon… I did a Edco grinder from Home Depot in preparation. Dimensions are 24 x 26. Spent about 2-3 hours grinding it and got a lot of dust. But now upon closer inspection I see some areas are still pretty smooth. What would you guys do? I really don't want to go rent that beast again. Should I touch it up with some acid etching or do you think I'm good to go?

 

[LegacyIndustrial]

If you don't want to rent, do a good acid etch.
Check our FAQ Section for proper instructions.

 

[streetdaddy]

Ok.. Thanks Scotty. I'll do a supplemental acid etch just to make sure. You only get one shot.

 

[jake75]

i experienced the same thing i went back and used a hand grinder in spots

 

[James-W]

i experienced the same thing i went back and used a hand grinder in spots

I think that is a very good idea. A hand grinder should take care of it. It will take some time and some hands and knees work but it should produce some good results.

 

[wagspe208]

It is not great. Sorry.
A job is only as durable as the prep. I hate acid etch, as it rusts everything in a mile radius.
I rented a big *** grinder. I think it was 28". Still not a fast process.
Wags

 

[SunsetsAndFriends]

Spent about 2-3 hours grinding it and got a lot of dust. But now upon closer inspection I see some areas are still pretty smooth. What would you guys do? I really don't want to go rent that beast again. Should I touch it up with some acid etching or do you think I'm good to go?

streetdaddy - I feel for you. Right now I'm in the process of prepping my garage floor (510 sq ft), which is in my basement. I first removed a curing sealer using my 7" Diamabrush that I purchased from Legacy Industrial. Then I rented a 10" upright grinder from HD, and after grinding for about 14 hours, I thought I was done. The next day I looked at my floor and realized that the floor really wasn't ready. So the following weekend I rented an upright Edco 10" grinder. I ground for an additional 16 hours, going over the entire floor several times. The floor is flat and pores open. Now, I'm edging with a Bosch grinder that I purchased. I was going to rent but at $80 per day, it made more sense to purchase, especially because I plan to do the rest of my basement next year. One might say I went overboard with the grinding. But from everything that I've read on GJ, prep is most of the work. The coatings go down in just a few hours. So I aired on the side of caution and ground the floor, probably more than needed but this is my insurance.

Don't be afraid to spend the time and be methodical. That Nohr-S is very expensive. If it peeled up because of too little profile, that would be a very expensive mistake.

Good luck.

My experience and 2 cents.

 

[streetdaddy]

Thanks guys. I rented a hand grinder as well but that thing was very aggressive. Seems like i would have divots everywhere with that thing. Hard to make it level with that thing.

 

[SunsetsAndFriends]

Thanks guys. I rented a hand grinder as well but that thing was very aggressive. Seems like i would have divots everywhere with that thing. Hard to make it level with that thing.

What kind of hand grinder did you rent? I bought a Bosch CSG15 concrete grinder. It has built in dust collection. I find it very easy to grind flat without leaving swirl marks and the dust collection is amazing. This is what I would recommend.

 

[boobag]

that floor looks awefully rough, and will probably show through the finish.

 

[wagspe208]

Depends on system he uses.
I used Tennant Epoxy as a primer, then Tennant Expoy with color added as a thickness builder, then coated with Tennant Urethane with color, as it is not uv sensitive, and chemical resistant as HE**
Wags

 

[streetdaddy]

Now your scaring me! I definitely don't want to see swirl marks thru the finish. I am using Nohr-s, which is supposed to be a paint like consistency.

Will acid etching even it out? What do i need to do here to get a nice smooth finish? The product I'm using is high gloss, so im guessing it will show imperfections.

I used the rental makita grinder with a rigid cup shaped disc.(50$)

 

[LegacyIndustrial]

If you put down three coats, you should not have much issue.

If you are concerned rent a Diamabrush set-up from THD rentals. Concrete prep tool is the correct one. It will prep and smooth out any rough ground areas.


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[SunsetsAndFriends]

Now your scaring me! I definitely don't want to see swirl marks thru the finish. I am using Nohr-s, which is supposed to be a paint like consistency.

Will acid etching even it out? What do i need to do here to get a nice smooth finish? The product I'm using is high gloss, so im guessing it will show imperfections.

I used the rental makita grinder with a rigid cup shaped disc.(50$)

To give you perspective, my coating project is my first. But I have read many, many forum posts on a full array of topics. A big lesson that I gleaned from many posts is that prep is most of the success or failure of a coating.

Many posts stated that one should not expect the coating to "fix" imperfections in the concrete. In other words, concrete imperfections will show through. Think of it like this, 20 mils of coating is only 1/64". If you have any imperfection that is not less than 1/64", then it will show through, provided you put down 20 mils, which is 100% solids applied at 100 sq ft per gallon.

To get a nice smooth finish, I think that the floor needs to be evenly ground. There will be some roughness to the surface, which is what you need to be sure the coating adheres. It's things like gouges and deep swirl marks that you want gone, because they stand out.

My 2 cents.

 

[SunsetsAndFriends]

If you are concerned rent a Diamabrush set-up from THD rentals. Concrete prep tool is the correct one. It will prep and smooth out any rough ground areas.

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And I would watch the Nohr-S video put out by Legacy Industrial, where they show at 1:08 the correct method for using the Diamabrush. In the video they show moving the Diamabrush slowly, allowing the DB to grind before moving on. They do not swing the DB back and forth like a buffing process. Following their method will make sure that nothing is missed.

 

[streetdaddy]

Thanks diymyself. Will try with the db and post repost with pics and after the coating. I have 2 small kids and am having a hard time finding time to redo.

 

[wagspe208]

IF you want it to be bad ***, rent one of these. It is planetary action. It has a big *** dust collector that works awesome. I rented a 32" one, 220 single phase. It was 400 for the weekend with dust collector.
It was a bargain at 400. Ground its balls off. VERY LITTLE DUST escaped. It has a vac want to vac everything after grinding. Paint.
Wags

 

[wagspe208]

Here is a pic of the grinder with dust collector.
Wags

 

[SunsetsAndFriends]

Here is a pic of the grinder with dust collector.
Wags

Now that would have been the way for me to go with mine. I'll bet grinding would have been much quicker and less hassle.

 

[SunsetsAndFriends]

Thanks diymyself. Will try with the db and post repost with pics and after the coating. I have 2 small kids and am having a hard time finding time to redo.

I have kids myself. Time can be the scarcest resource at times. With my garage floor, I just decided that no coating will go down on the floor until the floor is ready. I've put in a lot of hours.

 

[streetdaddy]

Who rented you that beast Wags?

 

[rburke65]

Yes, from whom did you rent that.

 

[Jaguar Fan]

What brand is that beast? I can make out the "800" but not the name.

Actually, can you post a hyperlink?

 

[wagspe208]

I believe it is a husqvarna. I rented from Jon Don..... a floor place. Many a rental house do not have the planetary setups. Many a floor place that sells epoxies will.
http://www.husqvarna.com/int/construction/products/surface-preparation-products/
I believe they are nation wide. They had a bigger one, and an LP one. It is a beast. ESPECIALLY with the dust collector.
Wags

This one weighed 500#, the bigger one was 800+

Jon Don
http://www.jondon.com/