advice needed, is there a tutorial to help?

Starla DuPresStarla DuPres
in General
hi everyone, I'm in need of some help. I recently did a course in prosthetics but now i have sculpted a head and would like to cast that and have no idea how to do it. i have some platsil 10 but thats it, and I'm not sure it would even be enough for this project, its a human head. 

So what i need to know is the casting and mould making process for a human head sculpt in chavant. either one of the tutorials i can purchase or a step by step walkthrough would be amazing.

thanks so much 

Comments

  • Chris EllerbyChris Ellerby Admin
    edited August 2014
    Molding a sculpted head can be pretty close to lifecaseting, depending on the type of head you sculpted.  

    This lesson shows making a silicone lifecast of a head, with a plaster bandage mother mold.  (You can use fiberglass, epoxy, or plaster for yours, as you don't have the same time/weight constraints as lifecasting):

    If you just want to make a 2 part stone mold this tutorial is great:

    And here is an amazing mold making tutorial that covers all kinds of techniques: (HIGHLY recommended)

    Here is a rough rundown of what you would likely want to do for making a head mold.  Depending on the sculpt, I would likely do a glove mold.
    1. Seal your sculpt with a layer of krylon crystal clear
    2. Mix up a thin batch of silicone and brush it all over the head, making sure to push it into all the details.
    3. Before the first coat fully sets mix up a batch of silicone with some thickener to get more of a frosting consistency.  Brush and spatulate that on all over the mold, using it to simplify the form.  Pack it in behind the ears, under the nose, in the eyes, under the chin.  The goal is to  make the outer form as smooth as possible.  You will also want to make sure the back center of the head (where you will eventually cut) has a bit more material built up.  And you can also build a flange around the base of the head, out onto the table, which can help a lot during casting.
    4. Repeat step 3 1 or 2 more times as needed.  For your last layer, set in some registration keys to help the mother mold align properly.  This can be as simple as strips of silicone, or you can go as far as to have pre-made keys handy.  One good way to make a lot of keys ahead of time is by pouring silicone into ice cube trays.  As ice cubes have a tapered bottom (which becomes the top of your key) they make great keys that help registration without the risk of locking up your mold.
    5. Once the silicone is fully cured make a 2 part mother mold out of fiberglass, epoxy, plaster bandages, etc. 
    6. Remove the mother mold, and cut up the back of the head in a zig-zag pattern with a sharp blade until you feel you've cut far enough to slide the head out.  The zig-zag pattern helps the cut register back into place and prevents it from slipping around when you start casting in the mold.
    7. Remove your clay, clean the mold, and start casting!
    Obviously there are a lot of specifics and details missing in that list, but that's a general overview.  I highly suggest watching the lesson by Rob Freitas.

    Happy molding!

    /Chris
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