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When buying a cement mixer you must look at what the overall cubic feet of the cement mixer is. Most manufacturers will say that the total volume of their cement mixer or drum capacity is 9 cubic feet. This 9 cubic feet is really 6 cubic feet of batch output for the cement mixer (remember cement mixers do not mix straight up and down they mix on an angle which means the entire drum is not used all at once, only about 2/3 of the cement mixer).
Another way of looking at a cement mixer is to look at the total weight the cement mixer can actually mix in one batch. If a cement mixer rates its capacity at 250 lbs of cement, then you must remember that 1 bag of Portland cement requires 500 lbs of material. This means that the cement mixer will be able to handle a bag (80 lb) of Portland cement plus sand, gravel and water in the cement mixer.
So you must ask or realize that if the cement mixer has a rating of 1-2 bags and it is only a 5 cubic foot cement mixer it is based off of pre-mix bags. Because 2 bags of regular cement or (Portland cement) would require a 1000 lbs of mixing material to complete the job and any towable cement mixers cannot handle that, only in industrial sized batch plant.
Concrete Mixing Tips: Volumes & Weights of Materials * 1 Bag of Cement = 88 lbs. * 1 Cu ft. Sand/Gravel = 85-100 lbs. * 1 Cu. ft. Plain Concrete = 140-150 lbs. * 1 Cu. ft. Water = 62-65 lbs. * 1 Gallon of Water = 8.33 lbs. * 1 Cu. Yard = 27 cu.ft.
CONVERSION CHARTS * Average maximum load = 200 lbs. * 2 cu. ft. = 6 sq. ft. 4" thick * 2 cu. ft. = 8 sq. ft. 3" thick * 1 yard = 27 cu. ft. * 1 yard = 80 sq. ft. 4" thick * 1 yard = 108 sq. ft. 3" thick * 1 80 lb. bag = 2/3 cu. ft. * 1 80 lb. bag per fence post
How to Mix Sand & Gravel * Use an 8-1/2 x 12" square point shovel. * Portland cement, gravel or round stone and masonry sand. * Start mixer in motion. * Put in 2 gallons water. * Add 6 shovels full of gravel or round stone. * Add 2 shovels full of Portland cement. Slowly add 4 shovels full masonry sand * NOTE: WATER WILL VARY ACCORDING TO MOISTURE CONTENT OF SAND & GRAVEL.
How to Mix Concrete * You will need approximately 2-1/2 gallons water. * Two 80 pound bags pre-mix concrete. * Start mixer in motion. * Put in 2 gallons of water. * Add one 80 pound bag of pre-mix concrete * NOTE: MIXTURE WILL BE VERY SLOPPY * Slowly add 2nd bag of 80 pound pre-mix concrete. * Add 1/2 gallon water slowly to obtain desired thickness. |