Death Masks Flashcards
- Negative Mold
- Positive Mold
Two Castings Are Made
A mold made from an object and used for casting a duplicate of that object.
Negative Mold
A reproduction of an object which is obtained from a negative mold.
Positive Mold
- Quick
- Inexpensive
- Easily Obtained
Advantages of Plaster of Paris
Use fresh plaster of paris becuse old plaster will not “set” satisfactorily if it has absorbed moisture from the air.
For Best Results
Instead, use:
- Rubber
- Plastic
- Porcelain
- Enamel
Do not mix plaster of paris in a metal bowl
Do not _____ the bowl or instruments in the sink.
- Tiny particles of plaster may create a blockage
Clean
- Salt
- Warm Water
- Excess Stirring
- Metal Mixing Bowl
Hastens the Setting Time of Plaster of Paris
- Vinegar
- Cold Water
Retards the Setting Time of Plaster of Paris
- Apply a light oil to the skin
- Cover eyelashes, eyebrows, mustache and hairline with a liberal amount of petroleum jelly.
- Cover cranial hair
- Consider hand and wrist hair
To Preare the Skin and Hair
- A bathing cap
- Oiled Paper
- Damp Toweling
Cranial hair may be covered wtih these
This hair may need to be shaved
Arm and Wrist Hair
It will cause it to be pulled from the skin when removing the mold.
If plaster of paris penetrates through to the hair
Their purpose is to confine the wet plaster.
Dams
- Clay wall
- Cardboard frame- covered with oil, massage cream, or petroleum jelly to prevent absorption of water.
Types of Dams
- 2 quarts- face
- Use coloring
- Add the necessary ingredients to speed upor slow down the setting time.
Place Water in a Mixing Bowl
Use to distinguish the mold from the cast:
- Laundry Bluing
- Ink
- Any water soluble pigment
Coloring
Methods:
- Flour sifter
- Sift through fingers
- Tap from a spoon
Add plaster until all the water is absorbed.
- Proper mixture will resemble dried mud.
Slowly Sift the Paster-of-Paris Into the Water
- Deep stirring- minimizes air bubbles.
- Don’t overstir- the first application must not be quick setting.
Stir the Mixture with a Large Spoon
- This step is very important if you are to achieve a good impression.
- Methods of application:
- Brush
- Flicking it from the fingers
- Spooning it on
- Air bubbles will cause small holes in the hardened mold.
- These bubbles can be eliminated by blowing on them.
Apply the First Application of Plaster
- These layers will supply strength to the mold.
- Apply with a spoon or spatula
- Finished mold- 5/8” thick.
- Determine any thin areas and correct them
Apply the Succeeding Applications of Plaster
- Test the plaster
- The mold is removed promptly to prevent dehydration of the tissues as setting plaster generates heat.
- Fresh plaster of paris will harden in about 15 minutes.
Remove the dam as Soon as Possible
Roll and fingernail into the plaster, a sharp, clean impression means the mold may be removed.
Test the Plaster
- From the hand- by working the fingers free
- From the face- by rocking it from side to side the break the suction.
- Shave any wide edges
- Set aside until the heat has dissipated
Remove the Mold
- Check for flaws
- Fill any imperfections
Inspect the Inside of the Mold
- Prepare the mold separator
- Prepare a hanging or attaching hook
- Prepare a new batch of plaster of maris and water
- Make a shell
- Thicken the side walls
- Saturate square pieces of gauze with plaster mixture
- Position the wire hook
- How to make a solid cast
Making the Positive Cast
- Fill the inside of the mold with liquid soap allowing it to be absorbed, or:
- A light oil is poured into the mold and carried across the thickness of the margins
Prepare a Mold Separator
Copper wire properly bent.
Prepare a Hanging or Attaching Hook
- A clean container
- No salt
- No coloring
Prepare a new Batch of Plaster of Paris and Water Using:
- Pour plaster into the mold
- Carefully, rotate the mold in your hands
- Pour plaster back into the mixing bowl
- Break any air bubbles
- Repeat these steps three times
Make a Shell
- Use a spatula and apply plaster to the margins so it flows inward.
- Keep the margin of the mold scraped to the level of the cast margins.
Thicken the Side Walls
This step is performed to strengthen the mold but it is not essential that it be done.
Separate Square Pieces of Gauze with Plaster Mixture
Gently place the wire into the plaster as it begins to harden.
Position the Wire Hook
- Make the first few pourings necessary for a shell cast.
- Fill the mold with plaster mixture.
- Jar several times- to settle the plaster and free any air bubbles.
- Position the wire hook as the plaster begins to firm.
To Make a Solid Cast:
- Drying time- at least 12 hours
- Pour water over the back of the mold to soften it.
- Place the mold face down on a soft foundation to absorb the shock of chiseling.
- A blunt cold chisel is placed against the margin of the mold at a right angle to the cast.
- Strike the chisel with a light mallet- this is done at various positions all around the margin of the mold.
- The process is repeated until the edges of the mold break away allowing the remainder to be easily removed.
Removing the Cast From the Mold
- Small holes
- Hair regions
Making Repairs
Scrape plaster from inside the cast and fill the holes with a spatula.
Repairing Small Holes
- Scrape down the normal projection.
- A pointed instrument is used to etch the hair.
- Eyelashes are cut away
Repairing Hair Regions
