wet or dry grinding concrete. Opinion share (3)

Source:www.stonediamondtool.com Date:2012/9/28 Read:1192

Raul Vera : Some toppings on the market can only be dry polished, so use a high quality vacume system and shrouds on all our equipment.
I f polishing concrete you can go wet or dry.
Some spaces have to be done wet, we use a high quality autoscuber to pick up the slurry, dealing with the slurry for disposal is easy, we use a Gelling agent to solidify before discarding that makes it enviromentally safe and legal.

Gregg Denton:  As a " consultant and independent sales rep " I should qualify myself before I put in my 2 cents. I have been a working contractor for the past 15 years.Starting in stone fabrication and restoration then adding concrete polishing as well. When I "recommend" a product to anyone it is only after I have personally used it and put it through its paces. If I wouldn't use it on my jobs I certainly am not recommending it. On wet verses dry, there are logical arguments for both methods. For the highest quality finish I don't think you can beat starting wet and then switching to dry polishing after you have applied your densifier. It is a fact of physics, that wet grinding reduces friction, keeps the diamonds cool and results in a superior less damaged finish to the concrete. In other words, less sand pops, less pitting and more of the small pores filled. Whether working wet or dry you still have to do a thorough job of cleaning the floor before you densify.
On to the " gelling agents". While this may seem like something new,it really isn't. SAP, aka, super absorbent polymers have been around for many years. They are the particles that absorb liquids in baby diapers. I have tested these products and agree that there is a place for them. I think we need to exercise caution when saying that they will solidify concrete slurry making it environmentally safe and legal. Just because your gelled slurry will pass the paint filter test, doesn't necessarily make it legal to dispose of in a dumpster or the land fill. The EPA requires your pH to be under 12.5 or it is considered corrosive. Ok, that is probably not a big deal on new concrete. What happens when you are grinding on an old slab that is a property being re purposed from a previous industrial application. There are any number of potential contaminants in that slab that will not allow for "legal" disposal by simply treating your slurry with a gel product. If that floor being processed was contaminated by oil, solvent, fertilizer, heavy metals or a long list of things,then your slurry is potentially considered a hazardous material. So what I am saying is, be careful with disposal of your waste products and take the time to find out if it is " legal " or not.

Allison Birkmeyer, CSI:  Thank you all for the feedback. I certainly do not claim to be an expert or even close to one. My intention was not to say one method is better than the other (or recommend/sell products or equipment), but to provide the information I've learned in response to a posed question. It looks like I should double check my resources.

@Marc and Gregg - you definitely have a point. I thought I was making an educated statement.

Since I'm learning - Does the slurry filling in the pores (created by the wet method) affect the densification process? Does it absorb as well?

Craig Walton : Allison,
here is some of what I have found by grinding wet. As stated earlier, by others, it hold down harmful silica dust, and is easier on the operator and other occupants, not to mention the building, the HVAC system and so on.
The way I and others collect the slurry, makes for a very clean floor. When cutting with aggressive metals, I use a wet vac with the squeegee attachment. If you follow the grinder, and immediately vacuum up the slurry, the floor is cleaner than dry vacuuming. When I start with resins, I follow with an auto scrubber, and leave a very clean floor. I feel it is much cleaner than a dry vacuumed floor. If you don't think so, run an auto scrubber after you have vacuumed up as much dust as you can. you will pick up a lot of dust out of the pores. This pulls dust out of the pores , ready to accept the densifier of your choice, applied to rejection.