DECORATIVE CONCRETE
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BY BRADLEY COOMES
How I Make
CONCRETE MARBLE W
hen most people think of concrete, they bring up images of sidewalks and driveways, roads, and buildings. Not the most glamorous of objects in our everyday lives, but they don’t really show off the diversity. I make decorative concrete countertops and furniture pieces, all unique works of art, all from concrete. My favorite thing to do with concrete is to make it look like a slab of marble. Why not just use marble? Marble is great but it is hard to find the exact pattern, the exact colors, in the exact shape you want. Finding a slab big enough to make a seamless waterfall edge countertop, matching your coloring is insanely difficult. With concrete, you can mimic the styles of marble, but manipulate it into shapes and designs you or your customer’s desire. There are some truly breathtaking examples out there, I continue to be amazed at pieces my contemporaries are putting out. I learned how to make concrete this way at the Concrete Design School (CDS), with this specific
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technique taught by Dusty Baker, and using his Dusty powder. This Dusty-crete technique is very simple to understand, but the potential is limitless. Finding the right balance and flow of the powder is an art form.
MIXTURE My mixture is constantly changing, no two pieces use the same exact mix design. Every piece I do has different design limitations and challenges. I use Buddy Rhodes ECC Admixture, the finest sand you can find (I use mason sand from a local quarry; it’s not the finest but the locals love having a local product like that), white portland cement, and then low doses of PVA RECS 15 fibers, acrylic fibers, silica fume, plasticizer, and pigment if needed. The admixture and fibers are the very last things I add to the mix, in that order. They both tend to bind the mixer up, so slowly adding them to the end helps to prevent that. The mix should have the consistency of taffy, you don’t
That's not marble, that's concrete.
Bradley Coomes
want it super fluid. Yet, it should be able to move around the form to make natural-looking veins. You also don’t want it so dry that it leaves massive voids on the face of the project that you'll have to fill in later. Make sure your fibers get fully mixed in. Your mix should feel stickier than regular concrete. DUSTING The crux of the process is how you dust the forms. Everybody has their own process, and every technique has its benefits. However you do it, you will be making something unique. I take about a half handful of powder and stand a couple of feet away from the form (you don’t need to be hovering over it). I throw the powder towards the form, letting nature do the rest. It should be randomly scattered throughout your form. You can always add more if necessary. In the same vein, you can also blow out the form and try again.
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11/30/21 12:40 PM
