Casting the Appliance

For this assessment, the final piece will be made with foam latex. This is because the prosthetic is to be flexible and move when the face moves. All foam latex systems are a combination of natural latex (concentrated sap of rubber trees), a soap to make the foam whip up to desired volume (foaming agent), a vulcanizer (curing agent), and a coagulant (gelling agent). Foaming agent is a substance which is safe to use however curing agent and gelling agent are both toxic ingredients. Below is a step by step which demonstrates detailed instructions of this process with images. 

Image one

What you will need:

- Gloves (latex free)

- Cloak

- Scales

- Mixer

- Spatula

- Latex foam base

- Foaming agent

- Curing agent

- Gelling agent

- Syringe

- Small plastic pot

- Timer

- Oven

- Large paint brush

- Two part mould

- Mould release agent
- Screw driver

Step 1: Set up equipment on the table. Put on the gloves and cloak.



Image two

Step 2: Place the bowl from the mixer onto the scales and reset the scales to 0.000. Pour 300g of latex foam base into the bowl. (Image one).

Step 3: Reset the scales to 0.000 then pour in the foaming agent which should be 20 per cent of the foam base, which in this case is 60g.

Step 4: Again, reset the scales to 0.000 then add curing agent which should be 10 per cent of the foam base which should be 30g.

Step 5: Place the bowl back onto the mixer and turn the mixer on at a maximum speed. This is done to make the latex rise and give it volume. Set four minutes on the timer.

Step 6: Once the four minutes is up, turn the mixer onto the lowest setting. and set the timer for six minutes. This is done to cut down the number of air bubbles and make the product smooth.

Step 7: Place the small plastic pot onto the scales and set them to 0.000. Add gelling agent. This should be 10- 15 percent of the foam base depending on the temperature of the gel. If the gel is warmer use less and if it is cooler use more.

Image three

Step 8: Use the syringe to slowly add to the mix for another two minutes. This is to allow the foam to become a solid. (Image two). Use the spatula to scrape off any latex that may have risen in the bowl and mix it in.

Step 9: Once the mixing time is up, use the large paint brush to apply it to the negative mould making sure it is applied thoroughly to avoid air bubbles and so that the detail will show up well when finished. This should be done quickly while the latex is still a paste like texture. (Image three).

Step 10: Fill the rest of the mould with the substance up to the edges of the mask which has been sculpted. 

Step 11: Place the positive mould inside the negative mould then squeeze the two moulds together. The latex should then squirt out of the sides. (Image four).

Step 12: Leave the latex to set. This should take 10-15 minutes.

Step 13: The product should then be placed in the oven for three hours. This is so that the product has fully set and has become a solid.

Image four

Step 14: Once the product has set, use a screw driver to spate the positive and negative mould. This should be done with care to prevent the moulds from cracking. The appliance is then ready for application. For long term storage, the foam piece should be powdered and placed into a plastic bag then sealed.