Eyeballs for special effects, Halloween, or animatronics really cheap.

Step 5 Shaping the eye

Many of the how to articles I read made use of irises printed on a laser printer.  Well this is all well and fine if you wish to go that route but I feel that it doesn't give a look of realism.  The iris is either flat or even concave, not convex and when light plays through your eye I feel it makes a difference.  I wanted my iris to be concave to cause light to play on it like a real iris.  Since I chose to work with plastic, I decided to heat the plastic just enough to be pliable.  This is a tedious step and I will admit to you right now I messed up several eyes before I got it right.  (4 to be exact)

-First I traced the dark circle you see in the picture.  I did this by tracing the 18 millimeter googly eye as a pattern.
-Next I lit my candle and carefully, applying a little heat at a time and rotating the eye so as to distribute the heat evenly within the circle.  I found that I could get sufficient heat by just holding the iris area so that the flame just barely touched the plastic for less than a second then rotating the eye.
-Once I had the plastic pliable enough I tried a number of items to give the "right" shape to the iris area.  The first image I used a convex washer with a rubber lining turned upside down to press the pliable plastic in until it cooled.  The second one I used the end of a wooden match stick and then a small coin to flatten the surrounding area.  I preferred the appearance of these and they make a later step much easier.
-I then sanded the guide ring I drew on the eye off so it wouldn't bleed through the paint.