Tag: skin

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Appliance Prosthetic – Test Casting 01

Well, Although I am waiting on some silicone additives (tints and flocking) to give my appliances a more realistic look, I decided it was time to do a test cast to determine how much silicone would be required for my nose prosthetic.

The first step was to prepare the mould with a release agent to make it easier to get the silicone out.  Since I have a limited budget I decided to use Vaseline applied with a brush and then heated with a heat gun to liquid state which the hydrocal can absorb – all excess was then wiped away with paper towel.

Once that was complete I pored out 20gm of PlatSil Gel-00 A & B into seperate cups and added a VERY small amount of Burnt Sienna & Cream Acrylic paint to Part B and mixed until even color. (It seems Acrylic Paint makes a rather cheap alternative to silicone pigments).  Parts A & B were then mixed together and pored in a very fine/narrow stream into the Negative mold until it was 3/4 full (which was about 3/4 of the mixture)  Then the Face cast was inserted into the Negative and pressure applied (At one point my entire weight) to help squeeze any large air bubble out and force it out through the ‘blend edge’.  This was then left to setup fully (Platsil has a 6 min work time, 30-60 demould – I left it 5 hrs due to work )

Excess Platsil after 45 minutes.

The Demould

It seems the Vaseline method as a release agent works amazingly well.  VERY little effort was required to remove the Negative with appliance inside from the Head cast.

The flashing on the outside peeled away with no effort at all.  The silicone was then given a light dusting with cornflour before removing it from the Negative.

With very little effort, and dusting with cornflour and a soft makeup brush as I proceeded, the entire nose appliance came out very easily.

Unfortunately the skin color is not right.  It looks ok in this image as the background it white – but when places on the palm of my hand the color contrast is very noticeable. It also looks too ‘dead’ as there is not enough natural mottling that skin has (I have the pigments and flocking for this coming as I write this article).  However – for a very first test cast I am ecstatic with the result.

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Appliance Prosthetic – Stage 2

From the raw sculpt I showed in my last post, I got to and smoothed and refined the detail in preparation for ‘texturing’.

To help get a very even surface to create my skin texture on, the entire sculpt was brushed down with isopropyl alcohol which slightly softens the plasticine and lets it blend smooth.  Once this was complete the texturing began.

Part 1: Large Pores.  Created with a blunt toothpick through plastic (to soften the edges)

Part 2: Small ‘feather’ pores.  Created with a stiff paintbrush also through plastic (lighter plastic than previous)

Part 3: Micro creased.  The plasticine in this case was stippled (with a stippling sponge) through 2 layers of plastic wrap.  This helped soften the previous pores and added the micro creases that all skin has.

 

The above 3 Parts were applied randomly, and in several ‘layers’ over previous parts to build up this nose texture.  Once I was happy with the result (and I am very happy with the results here) I started preparing for the negative cast.

So – What is this ‘outline’? you may wonder.  This is a drainage recess that will be part of the 2 part mold negative to allow any excess silicon a place to go.  After this the entire nose section was ‘boxed’ in ready to pore the hydrocal to make the negative.  BEFORE this however, all exposed plaster/hydrocal surfaces were brushed with Vaseline to act as a release agent and stop the hydrocal bonding to it. (I want to get them apart afterwards 🙂 )

The outer cardboard is simply to act as a support to ensure the plasticine doesn’t distort – but finally it is ready to pore.

Freshly pored, the hydrocal was set in less than an hour however I will leave it 12 hours before I try separating the 2 pieces (lets hope it worked) …