Material Identification

Hello,
I'm working on a group horror video project and have scenes involving rapid pregnancy.  We started using just plain old liquid latex designs and while the effect is being achieve, the latex after being stretched/inflated once can never be used again.  This makes 2nd takes, reshoots a nightmare as it can take a long time to make each inflatable stomach prop.

While searching online I came across some similar related effects, but am having the darnedest time identifying what material this is.  Some type of foam latex?  Silicone?  The elasticity appears to be very high and it can be reused over and over again.   

 
I know the attached photo may be of little help, but it's a photo of the props in the video being used.  Any identification or perhaps suggestions on a material that can achieve this effect but be re-used repeatedly would be incredibly appreciated.

Answers

  • Chris EllerbyChris Ellerby Los Angeles Admin
    Hard to tell the exact material they used, but it's possible that it's still latex.   One thing to keep in mind about latex is there are a lot of different types of latex bases out there, and different pigments.  Some pigments will weaken the latex a bit as well.   What type of latex were you using?   There is a variety called "balloon latex" that might work better for you.

    There are also materials like polychloroprene that are used in making balloons, but I have no experience working with it.

    We can rule out foam latex for that application, as it would not stretch that far and would not have same shiny surface seen in the video.

    Silicone is another option, but a bit more expensive.

    What types of issues were you having with your current implementation that made it not reusable?

    /Chris
  • edited July 12
    I used basically liquid latex (link below) painted onto a plaster mold with between 10-15 painted thin coats with a small amount of acrylic flesh colored paint mixed in.


    The issues is that it would stretch fairly well, but the elasticity would cause the latex to stay very stretched out and extremely rippled.  It would never even come close to it's original shape after being inflated.  Any suggestions on some types of latex would be much appreciated.  I tried looking up "balloon latex" but am having trouble finding some links to it.

    Also, maybe it's possible that I am not curing this properly?  I've just been pulling it from the mold and waiting a few weeks for it to dry out.

  • Chris EllerbyChris Ellerby Los Angeles Admin
    It's possible that their ammonia free latex went bad (or was just bad from the start), and it's also possible that it's an old bottle that sat for ages before selling, or even got a lot of UV/thermal exposure.  Hard to say.  My guess is that a better latex might do the trick for you.

    One latex that you can find online is RD-407 from Monster Makers
    https://www.monstermakers.com/rd-407-mask-making-latex/

    They have a variant that is already caucasian flesh tone pigmented that may be a good base to start with.  You would just need to do some tests to find out how many layers you need to build up to get the right effect.  Too thick and it will not stretch as much, too thin and it might tear.

    Based on what you said it sounds like your latex was fully cured.  It was likely just not great latex.  As latex is an organic material it can break down over time and exposure to different temperatures and UV can speed that up.  

    Ammonia is used in liquid latex formulas to preserve the latex.  Since you had an ammonia free latex it would have started breaking down much faster, and who knows how long it sat around in warehouses or the store shelf before it was purchased.

    I look forward to seeing what you make!

    /Chris

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