Well 1st you have to make a mold of whatever weapon you want to duplicate .
I've only used this stuff -
https://www.smooth-on.com/Pourable-Silicone-/c1217/index.html
You can find it at most hobby stores .
2 part mold
1. Get a box or some sort of container
2. take soft clay or puddy and cover the bottom of the box or container about double the thickness of whatever your trying to duplicate.
3. Embed half of the weapon in the clay , so thats all you will see is one half of it .
4. Spray mold release agent on the weapon and the clay thats exposed .
5. Mix you 2 part silicon or rubber and pour it over the weapon and fill the container or box .
6. Let dry and remove from box . leave weapon embedded in the rubber , very important .
7. Remove clay.
8. Put the rubber that has hardened upside down back into the container and now you will see again that one side of the weapon is exposed again .
9. Sparay mold release again on all parts . Attach (i use a straw) a vent hole so you have a pour opening .
10. Mix more silicon or rubber and pour over the rest of the weapon .
11. Let dry and seperate .
12. Now you have a 2 part mold of your weapon
HOPE THIS HELPS , AS FAR AS CASTING , ITS PRETTY SIMPLE.
1. Pull apart mold and spray casting release agent on both parts , let dry
2. put the mold back together and secure it with tape or clamps
3. Mix up 2 part resin
4. Pour resin into vent hole , fill the mold .and let dry - 10 mins usually
5. Pull your newly casted weapon out
