[SGII] Modular Starship Terrain AND CASTING (OT?)

Howdy All,

I have been doing a bit of mold making and casting of 25mm modular
starshp 
terrain I just wanted to relate my experiences to those who care.

Firstly, RTV Silicone is great!  I will never use latex for mold making 
again for this type of thing.  I used Polytek PlatSil 71-20 and it
worked 
like a charm I also tried Polytek PlatSil 70-25 and although it worked
it is 
not nearly as good as the other.  I just had to be careful of a few
things 
(as warned by others) like not whipping air into the silicone when
mixing.  
I had to paint the details before pouring and you have to pour
sloooowly.  
The most important thing as I can see is to have the entire process
planned 
out so that you are able to start and finish "the pour" without any 
hesitation while still not having to rush.  I had no big problems on my 
first 3 molds and I have been able to eliminate almost all air bubbles
now 
(a vibrating table is on my Christmas list <g>).

My evaluation of the dental cement I used in casting though, is less
glowing 
(Pemaco Ortho-Stone).  It works well enough, but it is pretty thick
stuff 
when mixed according to the box.  And when I have diluted it so that it
will 
flow well into the molds, I fear it is no stronger than hydrocal or
perhaps 
even reinforced plaster of paris.  My biggest letdown is that I don't
think 
I will be able to use this dental cement at all for the small, two part 
molds I have planned.  It is just too thick (they are about 1/8" x 6" x
3"). 
  But, I can still use it on some of the open face molds I have made and

will make.  It does mix very, very well and it has other advantages.

I then tried some Alumilite (resin) I picked up from the local hobby
store.	
This stuff works much, much better.  But, I think if I shop around I can

find a resin that is an even better match for what I want to do. 
Alumilite 
seems to exhibit too much shrinkage for what I am casting, and it has
such a 
short pot-life that it can be tough to pour it fast enough.  I am 
investigating a resin "RP40" by Thermocast.

I have uploaded images of the first few resin pieces I have done.  One
is a 
wall and a door (they are actually cast separately) and the second is a 
floor hatch.  I think I will end up casting all the floor hatches in
dental 
cement though as I still have about 24.5 lbs. of the stuff to use up. 
:-(

(if Hotmail mutilates these links you may have to cut-n-paste)

http://home.swbell.net/grog1/casting_images/first_wall_and_door.jpg

http://home.swbell.net/grog1/casting_images/first_hatch.jpg

Lastly, if this is too off-topic somebody just say so and I will shut up

about it, but frankly I am having a blast with this casting stuff.  I
highly 
recommend it to anyone that enjoys modeling.

Later,
Scott Clinton
The Grumbling Grognard

_________________________________________________________________