This Instructable uses a video produced in a project called Micro Mr Punch.
The method shown is how to start with an original detailed model in plasticine.
There is a video that shows this process in the last step.
There are other videos in this series, that show casting in plaster from plasticine, using the mouldings to recreate the model in durable in papier mache, costume making and more.
View Micro Mr Punch videos on YouTube:
Look at Micro Mr Punch phtots on flickr
Follow the Micro Mr Punch Blog on Blogger:
Step 1: Start With a Head Modelled in Plasticine
Plasticine is fabulous. It is so easy to model, and can be warmed to soften, and cooled to harden.
This instructable assumes you have made your original model...
Step 2: Find a Plane to Form the Mould Halves
Depending on your model, you need to decide where to split it, so it can't get stuck in the model. Avoid curvey bits like hooked noses, or it'll never come out!
Once you have decided on where the split will be, you cut into the model to a depth of about 1.5 cm all around. A scalpel will cut plasticine easy. You can also chill the model, to stop it getting distorted, and heat the scalpel to help it cut easier...
Step 3: Create a Cardboard Dividing Plane
By cutting pieces of cardboard and inserting into the grooves you cut in the plasticine, you can create a plane which will divide your eventual mould...
Step 4: Build Up the Mould Containers
You rnow need to create two open ended cardboard tubes from strong card, which will contain the plaster when you pour it.
Rest the cardboard inserted into the model on one of these, and seal the gaps with gaffer (duct) tape. Turn over and secure the otehr tube on the otehr side of the cardboard plane...
Step 5: Inside the Finished Mould
It will look like a cylinder with half a model at the base like this...
Step 6: Pour the Plaster Into the First Half of the Mould
Fill in one half of the mould, covering the half of the model that is visible. You should try to splash plaster into any details t avoid air bubbles getting trapped, before filling it in. You can also tap the mould to release any others.
Allow to dry - overnight is best.
When one half is dry, mix more plaster, fill in the other side, repeating the bubble deterring actions...
Step 7: Remove the Cardboard Round the Mould
It is best to let the mould dry for a day or more in a warm place, to avoid breaking the edges as you do this....
Step 8: Remove the Plasticine
Pick out the model...
Step 9: Clean Up the Mould
The edges may be sharp or overhand slightly if plaster has seeped under the cardboard. Pick off these trimmings carefully, and clean up by scraping with the edge of a blunt knife if required...
Step 10: The Finished Mould
Your will have two halves that look like this...
These can then be used to make papier mache casts from, with all the detail of your wonderful original.