Plaster Bandages FAQ
What are Plaster Bandages for?
As discussed elsewhere, there are two types of lifecasts- Bucket Molds and Layup Molds.
In a layup mold, the alginate is spread fairly thinly onto the surface of the skin, like in a face or torso mold. As such the alginate requires a structural support so it doesn't distort when it is removed from the body. Putting on a hard shell of plaster bandages keeps the alginate in its original shape so you casting comes out better.
Plaster bandages don't normally stick to alginate so several strategies are used to keep them together. More on getting plaster bandages to stick.
How Many Plaster Bandages Do I Need for a Lifecasting?
It is really important to have enough plaster bandages. Too few and your mold will distort and possibly collapse into a useless mess.
How to Figure
The bigger the mold the thicker the plaster bandage shell needs to be to keep the mold from distorting during the pouring up.
- For a face mold, 4 layers is sufficient
- For a head mold we need an average of about 5 layers
- For a half torso, we need about 5 layers
- For a full torso we need to have 6-8 layers of plaster bandages
A four-inch roll of plaster bandage contains 720 square inches of bandage (180 inches long x 4 inches wide)
- A typical face mold is a round bowl approximately 12 inches in diameter or about 115 square inches. Doing the math shows us that a face can be done with about 1 roll of 4 inch bandages. We include 1.5 rolls in our Face Casting Kit to be on the safe side.
- A head mold has a surface area of between 600 and 700 square inches. Because of that it requires about 6 rolls of 4-inch bandages
What Size Pieces of Plaster Bandage Should I Use?
How Do You Wet Plaster Bandages?
It's not difficult to wet your plaster bandages. Here are some tips.
What to Do
You've got your plaster bandages cut to length.
- Get a flat tupperware type container or a bucket of water.
- With two hands, one on each end, dip the plaster bandage into the water for about 5 seconds
- Take it out and gently squeeze out the extra water. You do NOT want to squeeze too hard or you will squeeze out the plaster as well.
- Straighten out the bandage and take it immediately to the model.
What NOT to Do
When applying the plaster bandage to the model, DO NOT stretch it tightly across the outside of the mold. DO lay it on the mold gently and rub it down gently. Stretching will put a downward force on any part of the mold that is "sticking up", like noses, breasts, etc. and potentially flatten them.
Do Plaster Bandages Stick to Alginate?
For many types of molds, you'll want your plaster bandage shell to stick to your alginate mold. Here are some techniques to make that happen.
Plaster Bandages Don't Normally Stick to Alginate
Nothing much sticks to alginate once it has set. The way to get something to stick to it is to embed something into the surface of the alginate while it is still liquid. Then when the alginate sets it will have something on the surface that will be able to grab the plaster bandage shell as you build it up.
Dry Plaster Bandage Pieces
Have some small pre-cut pieces of plaster bandage easily available. As the alginate is beginning to set, it will set from the inside to the outside. Take this opportunity to tap a bunch of small dry plaster bandage pieces INTO the outside surface of the alginate. They will be mechanically retained on the alginate surface so that when the first layer of the plaster bandage shell is applied the two plaster bandages will stick together.
Another thing that can be embedded into the surface of the alginate is a fibrous product used for stuffing quilts. It comes in sheets. Pull the sheet apart so it is just half as thick as it was originally. As the alginate is beginning to set, a sheet of this stuff is gently pressed against the alginate surface. When the alginate sets, the sheet is removed but it leaves behind thousands of little hairs. The plaster bandages can attach themselves to these fibers. Voila.
What Are the Different Kinds of Plaster Bandages?
There are different kinds and sizes of plaster bandages. What you want to use is determined by the type of project you want to do.
Plaster bandages generally come in 5 yard (15 foot) rolls
Plaster bandages come in different widths
- 3-inch (good for small projects like faces and heads)
- 4-inch (good for medium projects like heads and torsos)
- 6-inch (good for full torsos, but you have more control with 4-inch bandages)
- 8-inch (good for full bodies, but you have more control with 6-inch bandages)
- 12-inch (really too big for most lifecasting jobs)
- Regular Set (set in about 15 minutes- too slow for most lifecasting)
- Fast Set (set in about 10 minutes- still to slow for most lifecasting)
- Extra Fast Set (set in about 5 minutes- perfect for lifecasting)
We've determined that Extra Fast Set 4-inch plaster bandages are the best for lifecasting so that's what we sell. We sell individual rolls or boxes of 12.