1. The Lifecast Matrix
2. Measurement & Conservation
3. Traditional Molding Methods
4. Sculpture & Casting Mediums
5. Portrait & Precision Lifecasting
6. Erotic Lifecasting

Chapter 2: Waste Not, Want Not:
Systems of Measurement and Conservation

After deciding on a project design (LifeCastâ„¢ Basics: Chapter 4) and selecting a matrix (Advanced: Chapter 1), the next step is to determine how much stuff you need to do it.

This can be done by weight or volume as discussed in LifeCastâ„¢ Basics: Chapter 2.

The main points of that section bear repeating here:
• Do Not Mix Volume & Weight Measures in one project!
• To measure powders by volume fluff them up first!We use volume as the most practical for our purposes except in large projects where weight is easier and more accurate.

Displacement Measuring for Partial Kit Use:

If you intend to use just a portion of a kit or, to create more advanced sculpture, there are three things to measure:
• Water is the basis of all other measurements since it alone determines how much volume you can make.• ArtForm™ or Earthium(f/x)™, depending on which medium you are using.
• ArtCast™, PolyART™ or some other Casting medium: To pour the finished sculpture.

Displacement: This is by far the easiest and most accurate way of doing this with complex shapes like the human anatomy. This example uses an already calibrated measuring cup but you can do the same with any matrix after marking it off.
1. Put the object (in this case - hands) you intend to duplicate into your matrix and fill it with water. Mark the container at this water level (A).
2. Take the object back out and mark the matrix at the new, lower water level (B).
3. The distance up from the bottom of the container is the total volume of mold medium and water you will need (C). (Since neither ArtFormâ„¢ nor Earthiumâ„¢ increase the volume of the water significantly, you use this direct measurement to determine how much powder you'll need in your ratio (see LifeCastâ„¢ Basics).

Displacement

In this case C = 2 & 1/2 cups. If we wanted to use a ratio of 2:1 that means we would need half (1 & 1/4 cups) of mold powder. Remember to fluff up the powder before all volume measurements.
4. Measurement (D) is the distance between the marks (A & B) that you made in step one. That is the volume of casting medium you will need to fill the mold. In this case it is about 2 & 1/4 cups. This does not include any volume you may need for a cast base.

Marking The Matrix:

In the above example we have used a measuring cup that was already marked in 1/4 cup increments. Most containers used are not quite so conveniently prepared so we must do it for ourselves.

Using a measuring cup pour one cup of water into your matrix. Mark that level with something waterproof. Add one more cup, mark it again. Repeat this process all the way to the top of your container and viola, your matrix is calibrated in cups for displacement measuring!

Marking The Matrix:

Earthiumâ„¢ (f/x) Measurement is slightly different. Measure water volume as shown above but, use only Part A in that ratio to determine thickness or viscosity. Part B is ignored except to determine working and setting times.

An exception to this is when exact volume is crucial to your project and you wish to liquefy Part B before mixing into Part A. In that case you would take out a little of the initial water measured above to use with the Part B. The resulting total volume will then be preserved.

BlendBagâ„¢ Measurement:

Here is another option, especially useful when LifeCastingâ„¢ groups when each individual has their own matrix (several childrens' hands in small paper cups as in the StudioPackâ„¢ for example). Our unique BlendBagsâ„¢ are already marked off in cup increments so you can;

1. Fill the container(s) with water while the object is inside just like in step one above.

Measurement:

2. Pour all the water into a BlendBagâ„¢ and hold, suspended from the top as shown. Do not rest it on any surface.
3. Read the water volume on the lines printed on the BlendBagâ„¢ and use that to determine the amount of powder needed at your ratio.

Measuring Other Mediums:

POWDERS:

Plaster, Cement & Concrete and other powders would be measured in a similar way as explained on the previous page concerning our ArtCastâ„¢.

Each type has a different recommended ratio of water to powder however which should be specified in the manufacturer's instructions.

Mediums:

POWDERS:

Also, it is important to discover whether and by how much the addition of the water (or other liquid ) affects the overall volume of working medium produced.

Usually this is only learned by experience or by 'picking the brains' of technicians and educators familiar with the item.

LIQUIDS:

Thermoset Resins and other mediums which begin as liquids will typically be measured by weight to determine volume. Since these are typically rather expensive and or time consuming you don't want to waste them with mistakes.

This is where you need to know about a chemical's "specific gravity" to use as the basis of measurement. (See below)

LIQUIDS:

It is much easier and safer to use water to determine these volumes (see LifeCastâ„¢ Basics) than the mediums themselves. For example, fill the mold with water then pour this into a measuring cup. Or measure by displacement to begin with. Then calculate and weigh out the amount of resin and catalyst needed to equal that volume.

SOLIDS:

Waxes, Thermoplastic Resins and other mediums that are solid at room temperature are still measured by weight per volume. Then you need to find out how much a specific volume ( a cup for example) of that medium weights and do a conversion if the specific gravity is not provided.

Weight per volume can be found in the manufacturer's instructions or MSDS sheets in many cases. Sometimes you have to figure it out for yourself by melting some and weighing that volume then do the math before melting a batch.

SOLIDS:

For example: If the wax your using weighs 12 ounces per cup (a specific gravity of 1.5) and you need 8 cups then you need a total of 12 X 8 = 96 ounces or 6 pounds.

Weigh out 6 pounds or so and melt it. That should be approximately the correct volume.NOTE: In lifecasting a 'pour' of hot wax must be done all at once, it cannot be added to. As wax cools it will shrink slightly.

By 'topping off" an ArtFormâ„¢ or Earthiumâ„¢ mold some of the additional wax will seep over the previous, now condensed and cooling shell and ruin the details! (See Chapter 4)

Specific Gravity (aka: Relative Density):

The phrase "specific gravity" within this context refers to how much a liquid weighs on Earth at sea level as compared to an equal volume of water which is used as the standard.
• Water = 1.0 so a chemical thats has a specific gravity of 1.0 is equal to water. For example; water in the above conditions weighs 8 ounces per cup. Therefore if a liquid's specific gravity is 1.1 it would require 8.8 ounces (1.1 x 8) to fill a measuring cup with it.

Specific Gravity (aka: Relative Density):

• Since, by definition thermoset resins have 2 parts (usually called simply Part A & Part B) which frequently have differing specific gravities a little arithmetic will be needed on your part to calculate how much stuff a project will require.
• Specific gravity is always listed in a product's technical data sheets and/or instructions for use.

Go To Chapter 3: Mold Construction:
Traditional Mold Making Methods

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