Molding and Casting landing bay doors

The YT-1000 model I'm building has 5 sets of landing gear. I have molds for the landing gear but will need to make 5 sets of bay doors. So making a mold and casting them is the ideal solution.
Materials used:
Smooth-On's  OOMOO 25, Smooth Cast 300
Mann Ease Release 200

The doors are scratch built and are 12mm x 33mm and only .5mm to 1.5mm thick. This is the inner side.

And the outer side.

Here I've attached the parts to styrene strips, the larger filler pipe on the right, and smaller air vents above.





The grey part will be the landing bay bulkhead with the opening mechanism.

I purchased a pasta maker which allows me to roll my plasticine into nice flat sheets. I've set the parts onto the sheet. 




The parts need to set down into the plasticine so the rubber can't get under the parts.

This is after the first pour and this side of the parts have been cleaned up. Some stray rubber will find it's way under so you need to remove any bits.

The final pour and a block of rubber.

The mold release worked great, the two halves pull apart with no problem spots.

The two mold halves. I used some small scissors to trim any rubber away from the air vents and cut a funnel shape at the pour hole.

The mold is set up and ready to pour. It's difficult to measure how much casting material I'll need so I just guess and pour the extra into some standby molds.

Don't need very much for such a small mold.

The casting material has set up and oozed out of the air vents. That tells me the mold is full.





It's important to know that small amounts of casting material will set up more slowly than large amounts. Part of the chemical reaction in the mixed casting fluid creates heat, this helps in setting the solution. Small amounts will only create small amounts of heat. So it's a good idea to leave your cast in the mold until you are sure it's hard enough to handle. Too soon and you risk deforming the soft cast.

A perfect cast. A bit of flash where the casting material oozed into the space between the molds, not at all unusual and easy to trim off.

 
Here the parts are set beside the originals.

This is what the doors would looked like closed. On the finished model they will always be open.