Rotocasting / Slushcasting urethane in a silicone mold - A Materials Question

[MattMunson]

As the title of the thread says, I'm looking for a recommendation of a urethane to use for slush casting in a silicone mold. I believe this is the type of thing that ReevzFX does all day long. lol.

I'm NOT looking for speculation. I'd prefer to hear from people who have actually done this successfully, and are interested in sharing their results.

My experience in pouring urethane into silicone is that it beads up and pulls away from the mold when it gets thin. The only thing I've found that works when brushing on urethane is Smooth-On's Brush On line. However it's viscosity does not lend itself well to slush casting, even when diluted with mineral spirits.

Thanks!

 

[andy19422]

You need Smooth on 65D that's specially made for slush/roto casting I can recommend it.

 

[minifig]

Yep...I use 65D all the time for slush casting...it has a longer gel time than a fast cast style urethane.

M

 

[MattMunson]

thanks for the input guys!

Though I need to make a minor update to my request. I want to rotocast a FLEXIBLE urethane in a silicone mold. Something like a PMC780, which I have gotten great success with when pouring into dump molds.

 

[andy19422]

Never tried it but what about PT Flex Mold Making: Casting Rubber and Foam - YouTube They make different shores in it

 

[Sorenzo]

Been researching this a little myself, but no solid info as yet. I'm very interested to hear what others have to say.

 

[RacerMachX]

My understanding is that for batman style cowls, VytaFlex® 40 - Shore 40A hardness is the one everyone uses.
The mix is poured in and is smooth on the sides of the mold with a gloved hand.

 

[andy19422]

found this vytaflex flexfoam odst shin.MOV - YouTube

 

[bookface]

I've used the Poly PT flex series from polytek with good success. I used the 50 shore to make my Captain America mask. I looked at the vytaflex, but it has a 30 minute pot life, which is a LONG time to be slushing something. The polytek urethane has an 8 minute pot life, which is still longer than ideal for slushing, but much better. I found it best to do several coats. It's also translucent (clear amber), so it pigments really well.

They also do a 20 shore and a 60 which both have shorter pot life than the 50, so it could be worth some experimentation to see which works best. From the link posted above, it looks like Brick in the Yard sell them in the US.

 

[Beaker]

I have successfully rotocasted Task 16 in a silicone mold... works pretty well and consistent

- - - Updated - - -

http://www.smooth-on.com/tb/files/TASK_16_TB.pdf

 

[starbuckcylon]

Task 16 all the way. It works in my rotocaster great and it takes color well. But it does have an odd smell to it even after it cured.