Flat Moulds & Cutting Edges

We covered this topic in episode #61: battleswithbit... but this is specifically about cutting edges on flat moulds. The blog post for this episode is here: battleswithbit...
Cutting edges on appliance moulds do the work of separating the fine appliance edge from the flashing and excess, allowing the mould to close properly and achieve the feather thin edge you have sculpted.
The exact width of the distance between the cutting edge and the actual edge where the sculpt stops and the real skin begins varies between artists and techniques, preferences and materials. One thing is sure - make it too narrow and there isn’t enough mould to provide a stable cutting edge and make it too wide and you have an excessive amount of cap plastic bordering your piece which can cause unusual wrinkling, flatten hair or skin textures and generally make a piece have a larger footprint than necessary.
In a typical rigid core and mould made from plaster or resin, the ‘cutting’ action of the mould on the core is caused by the thin edge being pressed down using a clamp, strap or weight usually. The appliance material (usually silicone or foam latex) is essentially a liquid and therefore responds to the pressure exerted on it by the cutting edge (assuming the mould is accurate and material strong enough to withstand the closing pressure required).
With flat moulds, however, there is no core being squished into a mould. Instead, typically the back of the mould is left open and wiped clean with a rigid scraper to arrive at a clean border of cap plastic around the appliance. This clean border should have no silicone residue on there, which allows it to be then melted away on the skin later and thus blending into the skin.
Subscribe to the audio podcast 'Battles With Bits Of Rubber' on your favourite podcast app!

[@arabellamayer5209]

A nice prosthetic vid to cheer me up

[@SimulationTek]

Love it. Love that tour making more. Thank you both

[@chemicalcorrosion]

Awesome. And congrats on the 75th podcast!

[@sadieross-johnson2800]

Excellent explanation, thank you.

[@pinar9782]

Very very informative videos. Thanks so so so much.

[@TheEdvinas694]

hey I have a question, I'm a beginner at this I tried making a prosthetic with melting cap plastic edge but I couldn't melt it somehow I wonder was it too thick or maybe I didn't clean exes silicone properly and I was left with layer of silicone what could be the problem here ? also pros aid was not sticking well at all :D ....

[@monicalee2011]

hi Stuart, love your work. got the DVD from Mould Life. May I ask if I'm sculpting many veins that are close to each other, it means have to do the cutting edges for Flat mould?

[@stuartbray]

Hey! Thanks for the support. If you want silicone pieces with cap plastic encapsulant, then I would indeed do that. Personally though, I woukd make them in a flat mould but use a Prosaide Based paste such Bondo, Prosthetics Transfer Material (PTM by Tinsley is fantastic) or similar. That doesn't need a cutting edge doing as there is no cap plastic involved.

[@monicalee2011]

Thank you for responding so quickly. Appreciate :) @@stuartbray

[@monicalee2011]

yes, I'm using silicon pieces cap plastic encapsulant. regret doing so many veins in one small area :( taking longer than I thought to do cutting edges :(

[@monicalee2011]

yes, I'm using silicon pieces cap plastic encapsulant. regret doing so many veins in one small area :( taking longer than I thought to do cutting edges :(

[@SvenFx-22]

Where can I find the downloadable booklet for episode 61. Can’t find on website anywhere. Trying to help a student understand the concept and my words aren’t doing it haha

[@stuartbray]

battleswithbitsofrubber.com/61cuttingedges/

[@arabellamayer9195]

Hi Stuart. I am facing my bugbear: sculpting. So just to clarify, I have your mould at home from your course and I measured the distance between the prosthetic appliances edge and the flashing and sculpted it at the exact same distance. So should I instead push the flashing much closer to the edge of the prosthetic appliances Sculpt? Thanks, Arabella

[@stuartbray]

Be guided entirely by how big you piece needs to be. Often this isn't critical with flat moulds....if absolute precision is required then I'd usually do it on a core made from a lifecast so there is no question.
Whatever size your sculpt will be the footprint of the appliance will be larger by virtue of the cap plastic border necessary to contain and surround the silicone gel in the appliance and provide a blendable edge.
Ensure your sculpt doesn't start life too large is all. Pieces stretch easily but do not compress, so you can always pull out a small piece to cover more ground if needed.

[@arabellamayer9195]

@@stuartbray thank you 🙂

[@cristarenamastemakeup2465]

More bout this🔥❤️