shot blasting the floor

[Jagman]

Before applying epoxy,it is generally recommended to either grind or shot blast the floor. I have a pressure blaster. What type of abrasive would be used to shot blast a concrete floor? Is this faster- less messy - than grinding the floor?

I would like to hear from anyone who has done this.

John D

 

[Charles (in GA)]

A special machine is used that blasts a strip about a foot wide. It has rubber shields around it and blasts steel shot onto the floor and then ***** it up.

Charles

 

[LegacyIndustrial]

Jagman:

Pressure washing @ 2500 PSI is fine if you are going to apply a thin sealer.
It will not create enough profile for a high solids epoxy system.

Homeowners should consider renting a grinder or acid etching.
Shot-blasters require training and will eat your floor away FAST if you make a mistake.

Lastly, shot-blasters create corn-rows in the concrete and therefore need to be coated over with a thick high solids product or the corn rows will come through.

 

[Cruzin90]

Forget shot blasting, just grind it!

 

[rugerlady]

Jagman,
Shot blasting is not something you want to do. Acid or diamond grinding will do what you need. Diamond grinding is the preferred method. It is way too easy for a rookie to chew a floor up with a shotblaster.

 

[Bad Idea]

Shot blasting can leave blast lines in a floor that will telegraph through the coatings applied over it. Shot blasting is usually reserved for if you are trowelling a mortar or applying a full flake/sand broadcast thick enough to hide the blast marks.

 

[jakesterk]

Don't blast a cement floor. You will have a lot more issues if you do. I have seen blast rooms that have cement floors. They become etched in a really bad way.

 

[tncatadjuster]

Shotblasting is a perfect way to profile and clean a floor to be coated.

www.acepoxy.com

 

[Cruzin90]

Shotblasting is a perfect way to profile and clean a floor to be coated.

www.acepoxy.com

Too many risks involved though. Too much surface profile, lines, etc. If you don't do it just right, you'll be REALLY sorry.

 

[Jagman]

Thanks for the input! Grinding is the way to go.

 

[hldtyt]

After spending 12 hours removing a sealer applied by the builder, I would take my chances with a blaster! I had to take the electric grinder back and get the propane model. Easily three times faster than the electric. I will feel that mistake for days!

 

[Jagman]

Propane model? What is this? I thought all grinders would be electric? Home Depot tells me they have a unit for $80/day.

John D.

 

[theoldwizard1]

I can't imagine shot blasting concrete !

The real purpose of shot blasting is to increase surface hardness of steel.

 

[hldtyt]

Exact same grinder just powered by propane for indoor use. Lot more revolutions of the grinding head.

 

[Dominico]

Hired a pro on the side to do mine. Here is the end results of a shot blasted job. After 1 year of a harsh Michigan winter the floor still looks great!

 

[jdaallen]

Dry Ice blasting is the way to go. Cleans the floor better than anything but does not change or damage the surface at all.

 

[tncatadjuster]

Dry Ice blasting is the way to go. Cleans the floor better than anything but does not change or damage the surface at all.

a profile is needed, it is created by the media, no change is not desired, think about it.

 

[jdaallen]

a profile is needed, it is created by the media, no change is not desired, think about it.

It does nothing to the substrate (concrete surface in this case). Removes all grease, grime, dirt, paint, and anything else. Leaves a clean dry surface for what ever you want to do next. Instead of using hard abrasive media to grind on a surface (and damage it), dry ice blasting uses soft dry ice, accelerated at supersonic speeds, and creates mini-explosions on the surface to lift the undesirable item off the underlying substrate.

 

[Cruzin90]

It does nothing to the substrate (concrete surface in this case). Removes all grease, grime, dirt, paint, and anything else. Leaves a clean dry surface for what ever you want to do next. Instead of using hard abrasive media to grind on a surface (and damage it), dry ice blasting uses soft dry ice, accelerated at supersonic speeds, and creates mini-explosions on the surface to lift the undesirable item off the underlying substrate.

But, just a clean surface is not appropriate for epoxy or polyaspartic applications. You need a rough surface, often referred to as a "profile". You also need to remove concrete laitance if present.

 

[mato]

Shot blasting is not that difficult.... It can be (just like anything else) messed up, but just requires common sense and you will be fine.
It is much more effective, easier, and cleaner than grinding. You will generally have a vac unit that comes with the equipment to make it a self-contained set-up that will produce little to no dust.

If you are using a quality high build epoxy, you will not see lines from the machine.