Need help on an unusual project!

[Weps]

So I know the great things everyone casts on these boards and I need a little help. I need to make a couple small (sub 8") rocket models for use in a supersonic wind tunnel test. The master is currently being made on a cnc lathe for accuracy and then I'm hoping to make a mold in silicone and then cast the model with the mount in place.

Now for the juicy bits: The model is a standard cylinder, ogive nose, and has four fins. I need to know what would be the best way to mold it, either in a box in 2 layers or in one piece, and whether the resin will have a problem with low temperatures. I also checked and I don't have a smooth-on dealer near me, so any tips on getting the necessary supplies ASAP would be greatly appreciated!

Thanks in advance, and hopefully I can post some really cool Schlieren pics in a week or two!!!

 

[Reactor drone]

Since the body will come free relatively easily you could try a single piece with the pour sprue where the wind tunnel mount is then cut it to the fins for demoulding.

An alternative is to pour half the silicone up to the fin line,then apply a release agent to the rear of the silicone once it's set then pour the remainder.The section without release should stick together leaving the fin area able to be peeled back for demoulding.