Makeup Artistry - Jess Brown

Now that the sculpts have been transferred to the polyurethane cores and finished, it is time to make the second part to the snap mould. Figure 1 - Finished sculpt (Brown, J. 2021) The first stage is to cover the core in a layer of plasticine, excluding the keys. This is so the keys and recessed keys that will be made in the mould will fit together properly. A 1cm gap should be left between the plasticine and the sculpt, as this will be the cutting edge when the prosthetic is made. The plasticine was run through a pasta maker so that it was all the same thickness. This must be perfectly smooth with no gaps as this will show in the mould. Creating the cutting edge is very important as "if your cutting edge is too wide, you'll get a thick edge because not enough silicone will be pushed out of the way. If your cutting edge is too thin, the edge of the appliance becomes too difficult to distinguish." (Debreceni, T. 2019).  A clay moat/flange and wall is then made around the s...

After creating the master mould, the life cast can be used to begin sculpting. The sculpting process is the most important step when creating prosthetics. The sculpt is what the final prosthetic will look like, so attention to detail is key here.  To prepare the cast, it can be painted the same colour as the sculpting clay that will be used. This is helpful because it allows the sculpt to blend in with the cast and not look so odd, but it also helps the cast and clay to be seen as one uniform piece. Figure 1 - Painted ear casts (Brown, J. 2020) Once this has dried, it is important to make sure a separator has been applied over the top. When the basic sculpt has been finished, the clay will be floated off of the cast in water and transferred to the smaller cores. The separator is necessary to do this. Figure 2 - Separator for floating off sculpts (Neillsmaterials, no date) For this sculpt, Chavant NSP was used. This clay is a very popular choice as it is non-hardening and doesn't dr...

Now that a silicone mould has been made and prepped, the next step is to create the polyurethane positive/core for the snap mould. "Polyurethane is a plastic material, which exists in various forms. It can be tailored to either be rigid or flexible". (polyurethanes, no date). According to Dalchem, polyurethane is made of two components, those being urethane and polymers. These polymers are bonded together by urethane groups which then creates a versatile solution that can take many different forms. (Dalchem, no date).   Polyurethane has many different uses, such as insulation of fridges and freezers, car parts, mattresses, tyres and even shoe soles. (Polyurethanes, no date).  The polyurethane used was Axson F40 polyurethane resin. This resin has a quick setting time, a low shrinkage rate (meaning it won't shrink as it sets) and high abrasion resistance. (Neillsmaterials, no date). A catalyst is required for this, so isocyanate F40 was used, as per manufacturer's instr...

Snap moulds (also called conformed moulds, contoured moulds or squash moulds) are used to create a 3D prosthetic. They consist of a negative mould of the sculpt/piece, and a positive life cast that squash together. They can be made out of plaster, however these can easily break and chip, so a polyurethane mould will be created. Polyurethane is also lighter and more resistant than plaster, although it can be costly. As said by Todd Debreceni, "conforming moulds are becoming more commonly used in prosthetic application due to the ease and precision of the application process". (Debreceni, T. 2019). He goes on to say that this type of mould may not be suitable for all appliances, but he recommends them for smaller pieces.  As these are used to create individual prosthetics, they only need to be around the size of that piece. For example, if a nose prosthetic is being created, the mould only needs to be of the nose. This is accomplished in the first step using the master mould. A...