fine dust in concrete after grinding

[whm_fab]

Hi Folks,

I think i know the answer to this, but il ask it anyway in case there is an alternative.
I diamond ground my concrete floor last weekend in prep for epoxy coat.
I vacuumed up as much as i could with an industrial vac but there is still find dust embedded in the concrete, and when you wipe your hand on the surface it its obviously dusty. I can only assume this is not good enough to apply epoxy coat?

My question is - is power washing the only alternative ? i would really rather not power wash the workshop due to drying time and water getting everywhere etc, its not exactly hot weather here so there would be a big delay in getting the epoxy down.

If i have to do this, i know this is how long is a piece of string question, but after the surface wetness has 'dried' how long should i relaistically wait until all moisture is totally gone from the concrete before epoxy coating?

thanks for any help!

 

[mike93lx]

Definitely do not apply any coating when the surface is dirty.

 

[LegacyIndustrial]

This is common post grinding.
Broom it before you vac or blow, do this 3 or 4x. The broom will help loosen the dust in the nooks and crannies.

You will always have a little bit of dust, you just opened it up to a very raw state.

A professional will never use water to clean a slab. If you feel you need to go further, use denatured alcohol on a lint-free towel.

 

[whm_fab]

This is common post grinding.
Broom it before you vac or blow, do this 3 or 4x. The broom will help loosen the dust in the nooks and crannies.

You will always have a little bit of dust, you just opened it up to a very raw state.

A professional will never use water to clean a slab.

Thanks for the reply - so you would just recommend more vacuuming - brushing - vacuuming until it gets as clean as possible?

 

[benwah]

Invest a few bucks into a microfiber mop and a couple spare microfiber pads. I use the O-Ceder brand personally, it is a rectangular head and you can buy replacement mop heads.

I like to first give the floor a dry "mop" to trap as much dust as I can in the mop head. Remove the mop head and rinse it with warm water thoroughly until you get most of the dust out. Wring it out and set it aside to dry.

With a brand new mop head, do a thorough solvent wipe. This involves wetting out the mop head with acetone or denatured alcohol and mopping the entire surface of the floor. When you are finished rinse out the mop head with warm water, wring it out and set it aside to dry.

After your solvent wipe, make sure your original mop is mostly dry and use that to do a follow-up dry mop. This should remove most of your contaminants.

Nice grind job BTW!

 

[whm_fab]

Invest a few bucks into a microfiber mop and a couple spare microfiber pads. I use the O-Ceder brand personally, it is a rectangular head and you can buy replacement mop heads.

I like to first give the floor a dry "mop" to trap as much dust as I can in the mop head. Remove the mop head and rinse it with warm water thoroughly until you get most of the dust out. Wring it out and set it aside to dry.

With a brand new mop head, do a thorough solvent wipe. This involves wetting out the mop head with acetone or denatured alcohol and mopping the entire surface of the floor. When you are finished rinse out the mop head with warm water, wring it out and set it aside to dry.

After your solvent wipe, make sure your original mop is mostly dry and use that to do a follow-up dry mop. This should remove most of your contaminants.

Nice grind job BTW!

thanks for the tip! il give it a go on an area and see how i get on!

The grind wasnt all that bad, but SUPER slow. the workshop is just about 2000sqft and it took 2 full days, (9am to 9pm or so) but im pretty happy with the results!

 

[rjacobs]

we did a 3x wipedown with denatured... could have done 4.

We swept and vacuumed at least 2x if not 3x... prior to doing the wipe down.

700sq. ft. 3 gallons of denatured and 2 pads... I should have gone with 5 gallons. So for 2k sq. ft I would recommend at least 10 gallons of denatured alcohol and 4-5 pads so you can keep working while the other pads dry after cleaning them out of all the dust.

Dont try to use a pad to long either as you then end up just pushing wet concrete dust around and making things worse. You want the pad to pickup the dust.

 

[whm_fab]

10 gallons!! we dont really get volume stuff in stores like the U.S, first time i went to Texas i felt like honey i shrunk the kids with the size of the stuff i could buy. id say the biggest amount of that i could get here is half a litre and that would have to be from a chemist at an extortionate rate. in fact id say having 10 gallons of alcohol in ireland would land you in prison

 

[Black300zx]

A professional will never use water to clean a slab. If you feel you need to go further, use denatured alcohol on a lint-free towel.

Curious - is this because there is something inherently bad about wetting the ground slab, or is it because it would take to long to wait for it to dry?

 

[bigjon]

10 gallons!! we dont really get volume stuff in stores like the U.S, first time i went to Texas i felt like honey i shrunk the kids with the size of the stuff i could buy. id say the biggest amount of that i could get here is half a litre and that would have to be from a chemist at an extortionate rate. in fact id say having 10 gallons of alcohol in ireland would land you in prison

It might be called methylated spirits.

 

[whm_fab]

Curious - is this because there is something inherently bad about wetting the ground slab, or is it because it would take to long to wait for it to dry?

interested in the answer of this too !

 

[SolarColumbia]

I rinsed mine several times but it had over a week to dry before I coated it. There was virtually no dust on it.

 

[Kaizen]

Also made the mistake of grinding without the vacuum on it.
Also did not want to soak it due to time of install for epoxy. Vacuumed then when that was not working i got an electric leaf blower. big mistake. just put it in the air and came right back down everywhere.
Then i mopped. Used water and rag mop. changed the bucket about 30 times. I figured because i was not soaking the slab it would be ok. It did dry in a few days and i did the epoxy. No problems with adhesion. No way was this hack gonna spend money on gallons of alcohol lol. Put fans out after whatever you decide to do. i had 4 blowing for a few days.

 

[Kaizen]

thanks for the tip! il give it a go on an area and see how i get on!

The grind wasnt all that bad, but SUPER slow. the workshop is just about 2000sqft and it took 2 full days, (9am to 9pm or so) but im pretty happy with the results!

About the same result for me on my 1000sq ft. One day of it and i was beat

 

[Cairo94507]

We ground my 3-car floor down and used the vacuum bag attachment on the grinder which helped a lot. We then went over it several times with a vacuum to pick up all we could. Then we broomed it thoroughly and vacuumed it again. Then we took a high volume blower to the floor and that picked up some more. Vacuum again and then we wet mopped it a couple times and that floor was clean. I did all that just to start with a clean slate. We put down porcelain tile and it came out beautiful. Like everything else, proper prep is the key to a good job.

 

[Armorpoxy]

Hi
Once prepped and you vacuum it a couple of times there will always be some residual dust, its almost impossible to get it all out. A leaf blower works well to blow it out the doors too.

Whatever residual is left gets entrained in the epoxy or primer and shouldn't affect the outcome of the project.

 

[captaindiode]

Please be very careful with either denatured alchol or acetone over a large area. We had some custodians cleaning carpet glue residue off of a terrazzo floor with acetone when the air in the room ignited in a flash fire. One was burned pretty bad. It doesn't take much acetone poured out to create a hazardous situation. The spark from a light switch can ignite the vapors.

 

[nadogail]

With my dust mask on and the big door open, I used compressed air to blow the dust out of the concrete and onto the neighbors cars.

 

[LegacyIndustrial]

With my dust mask on and the big door open, I used compressed air to blow the dust out of the concrete and onto the neighbors cars.

Sent from my iPhone using Garage Journal

 

[GRivera]

Hi
Once prepped and you vacuum it a couple of times there will always be some residual dust, its almost impossible to get it all out. A leaf blower works well to blow it out the doors too.

Whatever residual is left gets entrained in the epoxy or primer and shouldn't affect the outcome of the project.

What method does Armorpoxy use to clean the dust after grinding?