LightWeightCement

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MIXING: The two most important things to remember when mixing are:

1) When mixing concrete or Hypertufa, first, thoroughly mix your dry ingredients. Keep mixing for several minutes until EVERYTHING is very thoroughly mixed. Get into the corners and all over the bottom of your mixing container being sure to get all dry ingredients. When the dry mixture is thoroughly combined, measure your liquid and add 1/2 of it to the dry. Begin mixing. It will be very lumpy and difficult to mix, but keep at it. After everything is evenly moistened, add 1/4 of the remaining liquid. Work it in until the mixture is evenly moistened. Check those corners and hiding places again, feeling for lumps and make sure they are thoroughly combined into the mixture. Continue adding liquid in small amounts, mixing after each addition, until the mix is the consistency desired for your project. When in doubt, err on the dry side.

2) Always sift the peat moss to remove any large lumps. These lumps will NOT dissolve and during the curing process will fall out leaving large voids in your trough.

Recipes

There are numerous recipes! The heavier your ingredients are, the heavier your final project will be. When reading a recipe for concrete or Hypertufa, cement should be the first ingredient listed, e.g.; 1:1:1:1 for a Hypertufa mix would look something like this: 1 part (cement), 1 part (peat), 1 part (perlite), 1 part (sand). In general, most recipes have a 1:3 ratio. They can be as diluted as a 1:7 ratio, although we would not recommend this, and can be as rich as a 1:1 ratio, depending upon the application.

To clarify and to prevent the purchase of an unwanted ingredient because the name was misunderstood, remember the following: Portland cement is NOT concrete it is an ingredient of concrete. Concrete, loosely defined, is mortar with gravel aggregate added. When in doubt, read the ingredients listed on the label.

Recipe #1 (1:1:1) (This first recipe is the most common.)

This recipe allows you to carve fairly soon while the form is still "green" (not dry and certainly not cured). It is recommended that you use grey Portland cement, however, you can use white if you wish. The grey will turn out looking like granite, provided the perlite used is small to medium grade.

Recipe #2 (1:1:1)

Nice fawn coloring without adding any colorant. Vermiculite adds a sparkle. Still very easy to carve, this mix is heavier, as vermiculite is denser, so a part will weigh more.

Recipe #3 (1:1:1:1)

Much more durable; heavier, yet still lighter than concrete. This will be lighter in color than any of the above, dependent on what type sand is used.

Recipe #4

Recipe #5 - for Hypertufa using a pre-mixed sand mix

The use of a pre-mix allows the beginner an opportunity to try Hypertufa without a large investment in materials. Portland cement comes in 94 lb bags. Quikrete, a concrete product manufacturer, does sell a smaller bag of Portland cement, but few stores carry it. Some home improvement stores carry small bags of pre-mixed concrete such as sand mix, mortar mix, high-strength concrete mix, etc.

Once home with the bag put the mix (still inside the bag) into a heavy hefty bag and push it around a bit. Mixes do tend to settle and you want the ingredients evenly distributed. Then take the pre-mix bag out of the hefty, and follow the directions below.

Recipe #6

Mix the dry ingredients first, slowly add water so that you can gently squish the mush with little water coming out. Now add a little bit more water and walk away for about 10 minutes. Check your mold set up or think about your next project. Then, back to the mix. Check it with your hands (of course they are gloved!) and add a bit more water, if needed.


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Last edited January 4, 2006 9:12 am by Nick
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