Lifecasting
Two-part silicone systems are used to create rubber molds used to cast resins, foams, rubber, and low-temperature alloys. A silicone mold generally requires little or no mold-release or surface preparation, as most materials do not adhere to silicone. For experimental uses, ordinary one-part silicone can be used to make molds or to mold into shapes.
Th decision to use this material for this project was to not only experiement with a new project, but because silicone life casting material doesn't shrink and can be used on multiple occasions to make several molds.
I have also known by researching, that silicone is much more expensive than alginate, but the advantage of using this silicone is that it isn't wasted.
Life form - a form of life casting silicone, used to create moulds, most on skin and body parts. I have never experienced using life form before, so it was a new experience for me. Life form is a 2 part silicone, and when mixed, causes the mixture to thicken up within a certain "working time" . I have researched a lot on silicone, and have noticed that silicone is easier to work with unlike alginate, and can be used multiple times to create several moulds. Life form is also able to pick up more details and textures than alginate, and is less likely to cause air bubbles. I purchased a 1kg batch of this material, as I only needed a bit for the face ( the main part) , which is the mould that needs to demonstate the most textures and detail. A 50:50 ratio is used, so for example, 100g of A, 100g of B. I used 250g of each, so the equivalent to one pot ( 500g ) .
When I first encountered using the silicone, it's extremely thick and far from runny. Once equal amounts of both 250g of A and B are mixed together evenly and thoroughly combined into one paste, it was then ready to start applying to the models face.
Methods vary on how you apply, some like to use a mixing stick, and others use their hands. I did however try both, and found that it was good to use your hands to get in all the edges and dips within the face/nose/eyes, and then use the mixing stick afterwards to "butter" the thickest layers on top.
The models mouth was able to breathe freely , as in advance I asked her the requirements in which she wanted the life cast applied, Vaseline was applied to the hairline, eyebrows and eyelashes to prevent the silicone from sticking. It is always an essential to ensure the model feels as comfortable as possible, and in this case, I was only producing from the top lip upwards in regards to the facial prosthetic, so she fitted the role perfectly. When applying, I did hesitate a first because I was expecting it to be as gloopy as alginate, but it was actually quit relaxing. There was no rushing to get it all on at once and in every nook and crany. I wiped it across the models eyes, almost as if it were applying a warm face mask, it was very smooth to work with, although when it ws curing it was getting stuck to my hands, which became a pain. But when applied to the face I was really happy that I managed to get it all in the right places, and have time to build upon the previous layer to thicken it up. I also had an assistant at hand, just in case anything were to go wrong, and to also keep an eye on the nose opening so nothing got caught in her nose.
Once the silicone had fully cured, it was a rubber-like consistency, every part of the face that was needed was fully coated with silicone and I fully enjoyed using it. The thickness of the material was lovely to work with, and I prefer this to alginate. there was no mess made with dripping and getting it everywhere ( bar the hands ) , and I just loved the fact you could take your time applying it and not have to worry about a 3 minute curing time like you would with alginate. It took about 10-15 minutes to fully cure, it was time to start applying the plaster bandages to the outer silicone to support it as a shell.
Plaster bandages, only 1 roll was really required for this cast as there wasn't very much to cover. I have an assistant helping me prepare these as I was applying the silicone. The bandages were cut to various sizes, and directly soaked in warm water, and then applied to the silicone.
A few layers were applied here, and this was when it was almost complete, every inch of the silicone was covered, and the plaster paris from the bandages was smeared in well so it would form a very hard outer shell to support the silicone. The nostril opening was left free for the model to breathe.
A close up shot of the opening to the nostrils, smaller strips of plaster bandages were applied around the nose well. All strips were rubbed in thoroughly so no loose bits were left unattended and untidy. I was very happy with the outcome of this.
What did you like or dislike?
This was one of the best parts of the project, I loved getting my hands stuck into the messy stuff. Having had the opportunity to use silicone, I will definitely use it again in the future, I loved how thick it was and how easy it was to apply. There was no mad rush to get it all applied which was another reason why I liked the material, it was a calm and relaxing environment for both me and the model.
I didn't really like how thick it was at first because I wasn't really used to using the material, but once I was using it, I found it really easy.
How could you improve?
I could of made my model a bald cap, and pushed the silicone mould further back so I had more of a surface area to work with when fibreglassing. I cannot think of anything more to improve on as the entir process went better than expected, and having multiple opportunities to do life casts, I am beginning to get used to the idea of applying alginate and silicone the correct way.
Once the mould was released from the models face, this was the outcome, I was extremely happy with the detail that was captured in the silicone, as seen on the pictures. The pictures don't really do the justice of the mould, but seeing it from a cameras point of view, you can see how the depth of the mould appears like it's actually stood out, which makes it appear risen up. I am extremely happy with the outcome of this mould, and I hope to use this material again for the future.