Casting the Appliance

List of Products, Tools and Materials Used

·         Mold Release

·         High Solids Latex Foam Base

·         Standard Curing Agent

·         Microcellular Foaming Agent

·         Standard Gelling Agent

·         Mixing Whisk

·         Paint Brush

·         3 Tie Down Ratchet Straps

 

 

Step-by-step Instructions for Casting the Appliance

1.    Now the two casts have been cleaned I can make my Latex foam prosthetic piece. Firstly I coated the cast that is the negative of my sculpt with mold release. This stops the mould of the sculpt getting stuck and makes it easier to separate.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.    I then started the mixing process. In the mixing bowl I added 300 grams of the Base, adding 60gs of the Foaming Agent (20% of the Base) and 30gs of the Curing Agent (10% of the Base). This would be enough to mould both the ears and the face cast.

 

 

 

 

3.    I put the bowl back under the whisk machine for 4 minutes on the highest speed setting.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4.    After 4 minutes I turned the mixer down to the lowest speed setting for 6 minutes. This is to break down the large bubbles.

 

 

5.    After the 6 minutes keep the whisk moving on the lowest speed for another 2 minutes then start adding the gelling agent. The measurement for the gelling agent depends on the room temperature it needs to be between 10%-15% of the base. If the rooms warmer, use less and if the rooms hotter use more of the gelling agent. I used 35g. Syringe the gelling agent slowly and evenly around the bowl to stop it from turning the foam into a lump. Then also use a spatula to help mix it well. After the 2 minutes switch the whisk off.

 

 

 

 

6.    Now the mixture is ready it’s time to fill the casts. Start by brushing in the foam, pushing it into the detail of the face and ears. Then scoop the foam into the casts.

 

 

 

 

 

7.    With the cast of the models face and ears press them into the casts of the sculpt. Hold the two halves together firmly to push out the excess foam you should feel the two cast lock together. Then place the ratchet straps around the two casts to hold them together more tightly.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8.    Once the foam has set the casts are then placed into the oven which is at about 80 degrees for approximately 3 and a half hours.

9.    When the casts have “cooked” turn the oven off but leave them in another 5 minute to slowly cool as the sudden change in temperature could crack the casts.

10. When you take the casts out wrap them in a towel to try keep the heat. Again this is so the temperature is lowered slowly.

11. Once they have cooled remove the ratchet straps. With a screwdriver place it between the two casts and slowly separate them. Don’t force it open as it might rip the foam mould. Once I had removed one half I was then able to carefully peel the mould off the second half.

12. I then had my final pieces which I washed with water and fairy liquid to remove any chemicals. It was then ready to use on my model.

 

 

 

 

13. If the cutting edges were really good on the casts, the mould should have very thin edges as shown on the picture below. The cutting edge is where I left the gap between the clay on moulding part 2 stage.

 

 

 

 

 

 

 

 

 

 

My first attempted of making the face prosthetic wasn’t great as the edges came out to thick. However I just used this one as a practise piece. The second prosthetic face piece and the first one of the ears turned out amazingly. The edges were incredibly thin which was perfect at it means they will blend really well into the skin. Now I’m looking forward to applying this for my assessment and seeing the final results.