Excessive concrete buildup can be removed from metal scoops and rods by soaking them in vinegar overnight, then washing them off with soap and water and coating them with mineral oil to protect the galvanization. Large Scoop – Should be clean and big enough so that you get a representative sample with each scoop, but small enough to not pour concrete out on the ground when you’re pouring into the mold.
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I would advise you to carry an extra set of each size of mold to every job, because you never know if you might be asked to make another set. Disposable molds are to be calibrated every time a new lot arrives. Whichever mold you are using, they will need to be watertight and resistant to damage from tamping, as specified in ASTM C470. If steel molds are used, mineral oil will also be needed to lightly coat the inside surface of the mold and keep the concrete from sticking to the mold. Cylinder molds – These can be plastic or steel, but we typically use plastic molds.Rodding is only used if the slump is greater or equal to one inch if the mix is very dry and the slump comes out to less than an inch you will have to vibrate the concrete to consolidate it thoroughly. Please make sure your rods are clean and have a smooth hemispherical tip before use, as specified in ASTM C143.
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