This Instructable will walk you through the process of creating a 2-part brush-on mold of an original.

2-part brush-on molds are ideal for replicating complex shapes that would otherwise be impossible with a pour (block) mold or glove mold. Using a brush-on technique gives the silicone more flex when demolding and require less silicone than pour molds. Splitting the mold into two parts can allow you to work around undercuts in a mold.

Note that you can add more than one mold part line, however this will increase the complexity of your mold.

In this Instructable I will be making a mold of a clay original that I sculpted and then creating a slush casting using the mold.

Materials I used include:

  • non-sulfur oil based clay (6 lbs)
  • clay tools
  • dragon skin 20 silicone (2x trial kits)
  • plasti paste mothermold
  • mixing containers (x20)
  • brushes (x2)
  • stirring sticks (x20)
  • gloves (a lot)
  • smoothcast 300 (1x trial kit)
  • mold release
  • wing nuts
  • 1/8th MDF board
  • sewing tape measure

Step 1: Create design

Start by designing your part.

I had a mannequin head around, so I thought it would be fun to make up some sort of futuristic spacesuit helmet.

The first step is preparing the base model for fabrication. If you're using a base model that you don't want to get ruined with clay or mold material it might be a good idea to cover the model in something silicone friendly (note that silicone has a hard time curing on certain material surfaces). I covered mine in plastic wrap and tape.

The mannequin head was obviously not to human scale and I wanted the helmet to fit my head. So I found my head measurements using a sewing tape measure then, added clay to the mannequin's head until it matched my measurements.

Next I sketched possible designs over a template. I included the template file I used.

Once I drew something I liked I started building and used the drawings to inform what I made.

It might be helpful to draw these at full scale so you can compare what you make directly to the drawings.

<p>alguien puede traducirme no le entendi nada no se ingles</p>
<p>Hola gentes, yo estoy empezando en estos y los materiales me suenan un poco a chino, con la arcilla a base de aceite hacemos el busto, y cuales son los otros materiales a usar? silicona liquida para que cree el molde y luego que es lo que le echa para que solidifique y haga las caras solidas? y luego al interior, para hacer el casco en si que utilizais? Estoy viendo que algunos ingredientes no son nada de faciles de encontrar.Gracias a todos.</p>
<p>Arcilla a base de aceite = plastelina</p><p>los dem&aacute;s son nombres comerciales</p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/ZCIO_2J1gF0" width="500"></iframe></p><p><iframe allowfullscreen="" frameborder="0" height="281" src="//www.youtube.com/embed/Fxk7zNn1hec" width="500"></iframe></p>
<p>May i suggest the use of 'Dividers' as pictured to make sure the model is symmetrical?</p><p>Other than that it is a very very good instructable and answered a couple of questions I have wondered about.Love it! Favourited!</p>
<p>Making the mold symmetrical would have saved me a lot of trouble getting the profile for the mothermold part line right!</p>
<p>And in a few years, this will be a forgotten art... the new generations will push the &quot;print 3d&quot; button, and voila!</p>
<p>Haha 3D printing is always an option but sometimes the best part isn't the final product, it's making it yourself!</p>
<p>This is a really great instruction set, thanks for writing it up. Did I miss a part where the clay dries out before making the partline? or does it dry completely?</p>
<p>The clay is oil based and never dries out. You can keep reusing it after each sculpt. I've had some oil based clay for years.</p>
<p>The more I read about this process the more confident I get that I could actually do this. I like to read about a process from multiple sources and get different people's takes on it before trying it myself. I feel like I get a better idea of what's it's actually like. So thanks for posting this. Before I try it I'll definitely be referring back here again.</p>
<p>That's the same approach I took before making my first mold. Post pictures when you try it out!</p>
<p>Wow! Nice idea! It is new knowledge for me. I get inspired from this post.</p>
<p>This turned out wonderful! Great instructions with easy to follow pictures, I feel confident I could do this given the time and may have to try for this Halloween! Thanks so much!</p>
<p>Glad you enjoyed it! post pictures when you try it out, it's lots of fun!</p>

About This Instructable


548 favorites


Bio: Hey there! I'm recent graduate of Carnegie Mellon University's Industrial Design program and a former Instructables intern. When I'm not working in ... More »
More by rlciavar: laser cutting Flat pack Laser cut chair Laser cut stencil bandana
Add instructable to: