Phurby asked where i had this posted, and i figures i'd add it here incase
anyone else wants to read it.
Ok guys here is my technique. Its pretty simple if you are comfortable with molds/casting.
Pic1 – Following the typical laytex rubber mold method, prep the helmet on a piece of cardboard, sitting above by about 1/8th “. I used clay to fasten it to the cardboard have it raised slightly. This is so the rubber seeps under the helmet a bit. Then, just alppy the rubber.
Pic 2 & 3. When the rubber is cured you remove the helmet. Note the hole in the bottom. You want it wide enough to be able to pour freely and see the plastic/resin inside.
Pic 4 & 5 – Pour a small amount of resin/plastic into the mold. NOT enough to fill it, just enough to coat the inside. Roll the mold around in you fingers so that the plastic/resin runs into all the crevases. This will leave you with a thin film coating the mold.
Pic 6 & 7 remove the helmet cast when its cured and you have a hollow copy of the helmet.
You can stop here and just use the helmet you have made. But it you plan on making a lot more, it may be helpful to do the next step also.
When making this tutorial, I was running low in rtv rubber so I didn’t do a 2-part mold for the final helmet.
I did a 1 part mold similar to the first process.
Pic 1 Now you can take the helmet you just made and prep it to be covered again. This time attach to the cardboard with a sprue. I used a piece of wax I got from Bantha5.
Pic 2- Cover with rubber.
Pic 3- Note the size of this hole. This is the pour hole created by the sprue used. You want it big enough to squeeze the helmet through when its cured. If you make a 2 part mold you wont need to worry about this.
Pic 4 & 5 After you fill this mold with resin/plastic, you will have a cast hollow helmet with a sprue to be cut off and sanded.
There is it. Hope this helps someone.