Trying to understand undercuts in relation to liquid latex casting

Just hoping to clear up a bit of confusion on my part. I understand that undercuts can be a huge problem when making things like foam latex, but I can't seem to find solid information on whether undercuts matter if you are just casting using regular liquid latex. Some sources I've seen still mention the undercuts in the sculpt, whereas others, simply talk about getting the clay out from the mold. I sculpted in WED and plan to seal with Krylon, and then make my mold in Hydrocal.

So, I'm trying to understand- are undercuts something to be concerned about if you are not doing foam latex? I have my sculpt finished, and I want to know if there is anything I should worry about before I cast (considering my sculpt does have some undercut areas). 

Hoping someone can clear this up a bit for me. Thank you!

Best Answer


  • Thanks! Yes, that helps. So I won't worry about the latex, then, in this case. Just need to make sure I don't lock my two halves of my mold. :)
  • Kai RottmannKai Rottmann ✭✭✭✭
    edited October 2018
    Okay :-)

    Hmm this can happen, if you doing the keys of the two parts wrong. When youre doing an undercut there, they will lock together xD
    You cant doing anything wrong, if youre doing the mold- walls in a 90° angle and the keys in form of a half hemisphere.
    If you would do these half hemispheres more than a half, it will lock.

    I remember that Timothy Martin explains in his course where to go with the outline of the mold and which release agents are important, so that the mold halves cant lock ;-)

    I wish you all the best for your project :-)


  • A+ for illustrations!

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