Running practice flat mould prosthetics

This blog entry will cover multiple practice runs of the flat mould prosthetic pieces. Using the negatives from the previous flat moulding blog to run silicone postives and create the prosthetic pieces.

First run process:

Figure 1

To begin with the prosthetic needs to be encapsulated with cap plastic as silicone alone will not stick or blend into the skin. To do this the moulds are coated with a release agent before been coated with 3 brush layers of cap plastic made in the ratio:

1 : 3

10g of cap plastic : 30g of Isopropyl alcohol

Figure 2 - 5

The colours used to create dimension in the prosthetic pieces, these are pre mixed on the side. The student chose the dark flesh pigment as it is cool toned compared to brown colour pigment.

Figure 6

The colours and painted into the depths of the negative flat moulds, this is done by taking a small part of the A and B from the silicone and mixing the colour into it, then painting the colours into the desired areas.

Figure 7 - 9

The colours are painted in layers until set, this test run the greens were painted first then the dark flesh tone last.

Figure 10

The back of the flat moulds is filled with the remaining FS10 silicone and a skin colour in the ratio:

10 A : 10 B : 20 Deadener

Once set the back of the prosthetic is encapsulated with the same cap plastic from the first step in 3-4 layers.

Figure 11 - 13

The back of the mould is powdered with talc and removed gently with a brush. This produces the positives.

Figure 14

In reflection to the moulds the student was happy with the designs, however there are areas of improvement for next time, such as: applying more release agent and focusing the cap plastic further into the detail as the prosthetics were difficult to remove from the silicone moulds resulting in damaging the negative mould. Next time the student will better match the skin to the model as she wasn’t available while doing this first trial, as well as change the colour order within the piece. The student will place the brown colour in first before the greens so its more visible when removed from the mould.

Second practice run:

Following from the reflection on the previous trail run, the prosthetic pieces are run again but with slight differences.

Figure 15

The cap plastic is brushed into the moulds the same however for this run acetone based cap plastic is used, mixed in the ratio 1 : 2

Using acetone compared to ipa based cap plastic, the layers seemed to evaporate fast and appear as nothing on the surface.

Figure 16 & 17

After the previous attempt going too green, in this trial run the brown pigment is added first to be more visible when removed from the negative, followed by a smaller amount of dark green. After mixing a batch of silicone pigment to match the model’s skin, the back of the moulds was filled with the remaining silicone.

Figure 18, 19 & 20

The finished flat moulds, also unhappy with this attempt the student did not like the colouring of the piece as it looks washed out and not readable from a distance. When removing from the moulds the cap plastic stuck to itself and created creasing visible in figure 18.

Third Practice run:

After two failed colouring attempts the student decided to run the flat moulds plain on the third run. Giving the opportunity to practice colouring the pieces before application.

Figure 21, 22, 23 & 24

With stress building as its reaching assessment day, this lesson was stressful for the student as a lot was planned to get done, this unfortunately effected the quality of work. After getting frustrated using the airbrush to airbrush the cap plastic into the moulds, the student mindset was not in the right place. The pigment was accidently made too strong. When scrapping and levelling the silicone it was pulling on the cap plastic layer underneath, thinking there was too much pressure the student stopped, this caused mass amount of silicone unfortunately making these flat moulds unusable as they will not blend into the skin.

However running the moulds plain gave the opportunity to paint the pieces as desired. This is shown in the next blog entry called ‘painting and application practice’

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Figure list:

Fig 1 - (Radfelder A, 2021) Flat moulds encapsualted with cap plastic, York College

Fig 2 - (Radfelder A, 2021) Silicone colouring, York college

Fig 3 - (Radfelder A, 2021) Green silicone colouring, York College

Fig 4 - (Radfelder A, 2021) Yellow silicone colouring, York College

Fig 5 - (Radfelder A, 2021) Colour sample mixed, York College

Fig 6 - (Radfelder A, 2021) Green layer painted into flat mould, York College

Fig 7 - (Radfelder A, 2021) Painted colours in arm flat mould, York College

Fig 8 - (Radfelder A, 2021) Painted colours in chest flat mould, York College

Fig 9 - (Radfelder A, 2021) Painted colours in extra pieces, York College

Fig 10 - (Radfelder A, 2021) Filled flat mould negatives, York College

Fig 11 - (Radfelder A, 2021) Finished chest flat mould, York College

Fig 12 - (Radfelder A, 2021) Finished arm flat mould, York College

Fig 13 - (Radfelder A, 2021) Finished extra pieces, York College

Fig 14 - (Radfelder A, 2021) Prosthetics ready to be pinned, York College

Fig 15 - (Radfelder A, 2021) Acetone based cap plastic, York College

Fig 16 - (Radfelder A, 2021) Brushed in brown pigment, York College

Fig 17 - (Radfelder A, 2021) Filled flat moulds, York College

Fig 18 - (Radfelder A, 2021) Second trial run chest piece, York College

Fig 19 - (Radfelder A, 2021) Second trial run extra piecs, York College

Fig 20 - (Radfelder A, 2021) Second trial run arm piece, York College

Fig 21 - (Radfelder A, 2021) Third trial run flat moulds fesh toned, York College

Fig 22 - (Radfelder A, 2021) Third trial run arm piece, York College

Fig 23 - (Radfelder A, 2021) Thrid trail run chest piece, York College

Fig 24 - (Radfelder A, 2021) Thrid trial run extra pieces, York College