For those who don't measure, follow instructions and like to fly by the seat of your pants. This Instructable is like mixing cookie batter. I originally created this to make the mold for a plastic ant farm.
Step 1: Materials You Will Need
You need to gather the following items.
1. Plaster Paris (can get at any hobby store, hardware store, etc)
2. A Bucket (I like to use kitty litter buckets because the come with lids)
3. A plastic cup
4. A stick to mix things
5. A messy place to lay things down.
Step 2: Mixing It All Together
1. Fill the bucket about 1/3rd the way up with water.
2. With a cup sift plater into the water, you will need about 8 - 10 cups for this project
3. Gradually stir
Once the water becomes milky and clumps start to rise to the top you have a good consistency.
It may not seem so at first but with a milk-cream mixture it will begin to harden rather quickly.
Step 3: The Pouring Stage
1. Layout boards, plastic or wood
Use flat even pieces.
2. Begin to an introductory layer, wait a few minutes for it to settle
3. Apply second layar on top of introductory layar
Repeat last step until height is ready
4. While the plaster is still a bit wet, take a knife or sharp edge and slice between pieces. This will make it easier for things to move around.
Once you have built up an organic object to your liking wait for 24 - 48 hours to dry.
Optional: Use a layar of Shallack ontop of mold to keep for future use.
DO NOT MOVE UNTIL DRY
Step 4: Dry and Form
1. Once your piece has dried, go around with rough edges or undercuts and smooth down with sandpaper.
2. To Vacuform the mold keep it on the plastic or wood platform and place into Vacuformer.
Viola! You are done.
Keep in mind, the stronger the plaster is the more it will last for future use. For longer, less dry pieces it will most likely break after the first time.