FreeShip- Concrete Retarder, Set Control for "Cement All", Concrete Ready-Mix- (Prompt rebate on orders with 3 or more FreeShip items!)

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This is a commercial retarder for "Cement-All" concrete mix called "Set Control" made by the manufacturer CTS to slow down the set time of that fast setting concrete mix. It may work fine for other concrete mixes, but I don't know that, I have not yet tested it. I wanted to get it listed along with Cement-All which is a relatively new product we're offering (note that I've renamed the concrete from "Cement All" to "Cement-All" in this description so it will stand out clearer as a product name).

The instructions from the manufacturer are as follows:
"Dissolve Set Control into the mixing water. Use 1 to 4 packets [there are 25 grams in each packet] per 50 lb to 70 lb bag of Rapid Set products [Cement-All] to achieve the desired working time. A trial batch is recommended to fine-tune the working time to match job-site conditions." That mixing ratio is small. If you're making only 50 or 100 gram batches of Cement-All how do you calculate how much to add and how do you measure such small amounts? Let do it first for those who are comfortable figuring percentages. If you chose to add one 25 gram packet of Set to 55 lbs of Cement-All, it just happens to work out to almost exactly 1% of Set Control per unit weight of Cement-All. 55 pounds = 24,947.58 grams, rounding off to get 25,000 grams (25 kg). 25 gr SC per 25,000 gr Cement-All = 1 gr SC per 1000 gr Cement-All = 0.1/100 = 1%. Then simply dilute the solid SC granules into a convenient number of gr (ml) of water, say a 100 or 1000 ml solution of water/SC and calculate how many ml of water will contain the amount of SC you need. There's a small error when done that way, but you're working within a wide range of possible amounts of SC to dose the Cement-All with, so it doesn't matter much.

For those of us who are mathematically challenged and who want to know how to manipulate the process to fit their own percentage quantities, it breaks down like so:
You would use 25 to 100 grams of Set Control per 55 lb bag of Cement-All which is 24,947.58 grams of Cement-All powder. Let's choose 25 grams Set Control (SC). Then for the number of grams of SC to use for 1 gram of Cement-All: 25/24,947.58 = .001002 gram of SC per 1 gram of Cement-All (CA) (rounding off that's 0.001 grams SC per 1 gram CA). We can flip that upside down for use later: 24,947.58/25 = 1 gram of SC per 997.9 grams of CA. Rounding that off we get 1 gram of SC to use per 1000 grams (1 kg) CA at a 25 gram per 55 lb CA concentration (you can also arrive at that by multiplying 0.001/1 by 1000 = 1/1000). If you were making a 100 gram batch of CA you would multiply the number of CA grams times the amount of SC to use per gram of CA: 100 x 0.001 = 0.1 grams of SC for a 100 gram batch of Cement-All. One tenth of a gram of Set Control per 100 grams of Cement-All.
Let's assume that you don't have a scale that will accurately weigh tenth's of a gram. What do you do? The solution would be to make a "solution": take the 10 grams of SC (Set Control) that you buy from us and add it to 100 grams of water (or you could use 1000 grams of water; let's stick with 100). Conveniently, when they set up the metric system they made water be the liquid whose weight in grams equals its volume in milliliters (ml). So, add the 10 grams of SC to 100 ml of water (100 ml = 3.38 fluid ounces). The easiest way to dispense ml of water is to get some syringes that are marked off in ml (or cc, 1 ml = 1 cc). You can buy syringes at a farm supply store which will have a variety of sizes for dosing animals with medicines or whatever. If you don't have a farm supply store nearby you can order syringes from suppliers of epoxies or other liquid resins. Back to calculations: you now have a jar of 100 ml of water that contains 10 grams of Set Control (SC). You need to add 0.1 grams of SC to your 100 grams of Cement-All. If you divide the 10 grams of SC that's in your 100 gram water/SC solution by 100 you get 0.1 (10/100 = 0.1). That's the correct number of grams of SC. To get the correct number of ml of solution, you only need to divide the 100 ml by the same number you divided 10 grams by, which is 100. So, dividing 100 by 100 gives us 1 (100/100 = 1). That's the number of ml of water/SC solution you need to add to your 100 gram batch of Cement-All, 1 ml of solution. You will need at least a small as 10 ml syringe to sort of accurately dispense 1 ml of solution. A 1 ml syringe would be better.

NOTES SPECIFIC TO CEMENT-ALL CONCRETE AND A SET CONTROL RETARDER MADE ESPECIALLY TO WORK WITH IT:

Cement-All has a short working time before it reaches what I call "soft-set". Soft-set is the time at which it no longer flows when a small pick tool is poked into the top surface of the concrete mix and the amount of concrete moved by the tool no longer slumps back into the mass, but stays in a raised position. The working time is the length of time before the soft-set time. Cement-All has the shortest working time of any of our 5 concrete ready-mixes. It is recommended that you use Cement-All for larger cross section masses than our 4 custom concrete mixes (2 White Arts, Tan Art, and Dark Art), which are intended for extra small concrete masses such as jewelry or small containers.
Cement-All can be modified to have a longer working time with the use of a concrete retarder. CTS has such a retarder we carry wich they call "Set Control". CTS gives the temperature range with which Cement-All may be mixed as between 42F and 90F. We test our concrete mixtures at a slightly elevated temperature of about 76F to 78F. CTS uses the temperature of 70F when listing Cement-All's properties and "set time" (15 minutes). I believe what they call "set time" is the same as "soft-set" time. I have another term called "hard-set" which I define as the time when a small pick will no longer create a mark or indentation on the top of the concrete's surface. The next section gives more detail about why Cement-All is more suitable for larger projects than our other concrete mixes.

Cement-All has a greater blend of pozzolanic and strengthening additives than our White Art concrete and so is potentially stronger than those concrete mixes #63-101 or #80-102 (the White Art mixes are limited to ingredients which are very light colored and most of the pozzolanic ingredients are darker). I say "potentially" because the actual concrete when set-up if used at a similar viscosity is not as strong as our other 4 concrete mixes because Cement-All is strongest when used at high viscosities. The sample tiles break easier compared to our other 4 concrete mixes at a given specific powder loading and at the same time in the cure cycle. Cement-All is more sensitive to higher water ratios than our other 4 mixes. The highest water ratio the Cement-All data sheet mentions is 5 quarts of water per 55 lb bag of the powder (that works out to 16.7g/3.2g powder/water). At that ratio the mix is just on the cusp of being too viscous. The most cited water ratio in the Cement-All data sheets is 3.75 quarts of water per 55 lb of powder (that is 16.7g/2.4g powder/water). At that water ratio the mixture is a non flowing paste unless it is mixed longer than our other concrete mixes (it can form a slow flowing paste if mixed longer, but ironically if mixed longer it can soft-set before it can be completely poured). At that water ratio when mixed for only 1 minute to gain additional pour time (compared to 2 minutes with the other 4 mixes) it is not practical for pouring into molds, it's simply too viscous and the setup time is too fast to fill your molds unless your object molds are shallow open face molds with very little detail. At water ratios that give a pourable mix similar in viscosity to the White Art Concrete Mixes (16.7g/3.4g for example), the sample tile breaks when cured for 24 hours (that being the time the data sheet says the mix reaches a reasonably high compressive strength of 6000 psi). It needs an additional 24 to 48 hours to reach a point when flexural strength is high enough for the tile to not break. Flexural strength, which is what is being tested when the tile samples are being bent with both hands in an attempt to break them, does not reach a reasonably high amount for 7 days, according to the data sheet.

What that boils down to, in simpler language, is that you will be wanting to mix your concrete to a pourable state, which will have too much water for the mixture to reach any kind of reasonable strength in a reasonably quick time. But not to fear, there are measures that can be taken to compensate for these deficits. The most obvious being to reserve Cement-All's use to larger projects with thicker walls. Another measure is to use "Set Control", a retarder made especially for Cement-All. If you slow down the soft-set time you will have enough working time to fill your molds adequately without raising the amount of water used and making a mix that needs a longer time to gain strength. You will have time to make thicker mixes with less water become workable. Other measures you can take are to raise the mass of the objects you will be casting. The larger the mass, the greater the heat of cure exotherm and the greater the strength of your castings, simply because they will be of thicker cross sections and those cross sections will cure faster during post working time. You can also raise the curing temperature. Keep the mixing and pouring temperature as low as possible to give yourself the longest possible working time and then move the still in mold castings to a warm area to speed cure, compensating for a higher water ratio (if needed) that you're using to make the mixture easily pourable (but, as mentioned above, if you use a retarder you may not need to increase the amount of water).
Another factor that leads to the above recommendation to cast larger sized objects using Cement-All is the size of the aggregates in Cement-All. Aggregate size is larger than in any of our 4 custom concrete mixes, and would not be suitable for castings which have very fine details with mold cross sections that are very thin; the aggregate size would not readily fill the mold (especially with the fast setup time of Cement-All).
The above discussion explains the initial recommendation to save Cement-All for larger projects than our 4 custom concrete mixes (#251, #252, #63-100, and #80-102).
Since Cement-All has darker ingredients than our White Art Concrete Mixes, it probably cannot be colored with pigments to give as bright colors as our White Art Concrete Mixes. However, it is the runner up in lightest color when compared with the White Art Concrete (it is slightly lighter than the Tan Art Mix), so it is possible it can take some pigments and give acceptable results. Currently, I am not able to spare the time to test pigments comprehensively as I did with the White Art Concrete. The best course of action for you would be to buy a small amount of some limited pigments and test the coloration yourself.