I don't know much about molds, but i did stay in a Holiday Inn Express Last night. :laughing:
Just teasin, When i was in Junior High , about 15 yrs ago, We made some simple molds out of plaster. We built a simple box to hold our subject piece, ( the box would unscrew for easy removal) The mold had two sides. I don't know if this would work, for deke heads. We were melting lead and pouring it into our mold through a pour hole. Then we had to polish up the piece, mine was a light bulb. I wasn't very creative.
I was thinking of carving some heads out of foam. Then making a mold using the above technic. Instead of foam i was thinking about using a product that i use in construction sometimes. It is called Rock Hard Putty, or water putty. It is a pouder that you mix 3 to 1 w/ water. This putty is very hard, and does not shrink. It can be mixed a little thin so that it could fill the mold nicely, It sets up in about an hour. It is not fully hard for about 24 hrs. but you might be able to take it out of the mold after two hours and it will still be a little "green" not cured, and could carve a little individual detail into it. My only concern is how strong the bill part of the head will be, but i believe that is the concern with any decoy head other than plastic. I might be able to drill a hole in the bill after the process is over and insert a heavy wire into it, i believe that has been mentioned in the past.
If i try it i will let you know, If you have suggestions let me know. With my mold idea, I believe that the product will be fairly ruff when removed from the mold, taking a little work to get it smoothed up.