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  • Lets mix it up a bit.

    Re some recent discussions of exact measurements and different systems of weights and measures, I have a head-scratcher.

    A bag of mortar mix has these instructions. Add approximately 3 quarts of clean water per 25 pounds of powder to a bucket, then add the powder and mix to a workable consistency. There is more to it not having anything to do with measurements.

    My scale weighs in pounds and ounces, also in grams and kilograms. My measuring cups are marked in quarts, cups and fractions of cups, and tablespoons. They are also marked in milliliters.

    I don't need to mix 25 pounds, I think 4 or 4.5 pounds will do the job. I did it mostly by guess and by gosh. If I had to do it again I would use the metric system. If the metric measurements were not available, how could I come pretty close by using pounds, ounces, cups and tablespoons? That part of the job is done, this is just to "stir up" some more discussion, and I just might learn something.
    Jim

  • #2
    Well you obviously need to think about this over a cup of tea. So buy a pint of milk and then you have a sensible sized building site friendly container to measure your water in. If you ditch the quarts in favour of pints it is a much more obvious rough calculation.

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    • #3
      Should be fairly easy since a liquid ounce of water weighs approximately 1 ounce. Convert 3 quarts to ounces = 96 oz. You are using 4.5 / 25th of the powder, so use 4.5/25th of the 96 oz. and that tells you to use 17.28 oz of water. You don't need to use a measuring cup. Just weigh it.

      Dan
      P.S. My math skills are failing. Please excuse any mistakes. The concept is to use the same ratio of water as the ratio of the powder.
      At the end of the project, there is a profound difference between spare parts and extra parts.

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      • #4
        "A pint of pure water weighs a pound and a quarter"

        Unless you're in some of the colonies, where it don't

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        • #5
          You should also eyeball the mix consistency and adjust as required. A tiny amount of extra or less water make a huge difference. One unknown is how much moisture has already been adsorbed from the air by mix powder.,

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          • #6
            Originally posted by Mark Rand View Post
            "A pint of pure water weighs a pound and a quarter"

            Unless you're in some of the colonies, where it don't
            In these colonies the saying goes "a pint is a pound the world around". Except in Olde Blighty and posessions, I guess.

            -js
            There are no stupid questions. But there are lots of stupid answers. This is the internet.

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            • #7
              Originally posted by Baz View Post
              Well you obviously need to think about this over a cup of tea. So buy a pint of milk and then you have a sensible sized building site friendly container to measure your water in. If you ditch the quarts in favour of pints it is a much more obvious rough calculation.
              Nah, I think you better buy a keg or two (UK or US, both units work) of beer, drink some of it and start adding water to the cement mixture. Drink more beer and add water until the mix look like "workable consistency"

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              • #8
                Originally posted by MattiJ View Post
                ...add water until the mix look like "workable consistency"
                Exactly. It's only mortar mix. Get it close by measuring and then fine tune as you go. Too dry? Add water. Too wet? Add
                some more powder. That's the way "backyard" concrete has been mixed as long as I've been around. It's not rocket science...
                Keith
                __________________________
                Just one project too many--that's what finally got him...

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                • #9
                  Originally posted by LKeithR View Post
                  Exactly. It's only mortar mix. Get it close by measuring and then fine tune as you go. Too dry? Add water. Too wet? Add
                  some more powder. That's the way "backyard" concrete has been mixed as long as I've been around. It's not rocket science...
                  Yes.... but you watch someone who does that all day and they know just what the right ratio is.... you don't often see them dripping in just a bit more, or another handful of mix.... In go a couple bags, and some water, and out comes just right mortar.

                  Concrete may be different... slump ratio and all that, I leave that stuff to the folks who know. For small concrete jobs, I know that a bit dryer is better than too wet, and just do as you say.
                  1601

                  Keep eye on ball.
                  Hashim Khan

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                  • #10
                    Thanks for the replies, weighing the water sounds workable. One site I looked at said to mix it to the consistency of mashed potatoes, another said mix to the consistency of creamy peanut butter, I mixed it a little stiffer than Jif. That seemed to work, had a good grab.
                    Jim

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                    • #11
                      Keith, I hope your sig line doesn't apply to me. Last week I mentioned the projects I'm into to a fellow I was talking with. As we parted he said, "I hope you get all your projects finished", I said "there's no way I'll ever have them all finished. How am I going to live to be a hundred if I don't have a project to keep me going?"
                      Jim

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                      • #12
                        Let's say you want to use only 5 Lbs of your 25 Lbs. That is 1/5th.
                        You need 3 quarts for the whole 25 Lbs.
                        That is 3.0 liters (approx).
                        Divide 3 liters by 5.
                        3/5 =0.6 liters or 600ml or just over 1/2 liter beer stein. If you have a German Stein with a 0.5 liter mark on the side (all German Steins made in Germany have it) - than just fill it to the top.
                        The space just over the 0.5 liter mark is for the foam.
                        3000ml : 5 = 600 ml = 0.6 liter

                        Now you know why you should use metric!
                        Last edited by Juergenwt; 04-08-2018, 07:09 PM.

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                        • #13
                          In this sort of thing I suppose metric would be less confusing. Generally I am unfamiliar with metric measurements, I know about what 5 gallons looks like, but I have no idea what 20 liters looks like. I suppose most people would be just as lost about the imperial system.

                          Too bad the digital scale doesn't have a decimal pounds option in addition to the pounds and decimal ounces option.
                          Jim

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                          • #14
                            I never quite trust in complete uniformity of mixture in bagged mortar mix - especially since they aren't giving you even a minute amount of "extra" masonry cement in the bag. If I'm not doing a full-bag mix, then I add a small amount of extra masonry cement to my fractional mix.

                            I use Home Depot's mortar-mix product - 15 or 20 years ago it had a poor reputation, but the current offering (Mason's Mix) is better received. For pure masonry cement, I use Iron-Clad, an excellent product available in New England (at least).

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                            • #15
                              With any of the premix it's good to have a bag of real mortar or portland cement to richen the mix a bit IMHO.
                              "Let me recommend the best medicine in the
                              world: a long journey, at a mild season, through a pleasant
                              country, in easy stages."
                              ~ James Madison

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