Foam latex, do I need a core?

Tanuki McLarnon

is it possible to make a foam latex skin without a core and injecting the foam latex? I dont need the skin to fit over anything exactly. Like, could I brush it into my mold much like Ted Haines did with brushing it onto foam? This would be a silicone life cast mold, then bake it as usual?

Also is there anything out there on casting something like a hand in foam latex to have it be able to accept the mechanics for a cable controled hand?

Chris Ellerby

Hi Tanuki,

You can bake foam latex without a core if you want a solid piece or a thin piece.  But if you want to achieve a specific thickness of skin you'll need a core.   You can only brush up so much of the foam onto a surface before it starts to slump and drain away.

We don't currently have lessons on glove making, but it's worth considering.  When casting a hand you need the core (fingers, etc) to be able to break down into multiple pieces so the core can be removed without damaging the skin.

/Chris

Tanuki McLarnon

Thank you for your reply! So I've heard of people covering the ball and socket joints of stop motion puppets with teflon tape to then cast over them. Do you think that might work for a cable controled hand?

Chris Ellerby

Any barrier that prevents the foam from getting down into the joints, which would inhibit movement, should work.  You just want to make sure the joints don't have to compress additional foam when they bend or have them get jammed up.   Otherwise, having the hands be solid foam should work out fine for you.

/Chris

Tanuki McLarnon

I was planning on doing the finger joints out of nylon tubing like Richard Landon did. Though, I'm not sure how nylon will fare in the baking process. the elbow and shoulder joint I was gonna use clevis joints. both of these I would wrap in the teflon tape before casting.

Chris Ellerby

Nylon should be fine.  The melting point of Nylon is 428 °F (220 °C) which is well above the temperature needed to bake the latex.   The temperature and time you bake at can change widely based on the application, formula, etc.  But common ranges are between 135°F and 175°F.   And I've heard of folks curing at much lower temperatures over longer periods of time with good results.

/Chris