Hey Everyone!
I was wondering what is the best thing to use as a pattern for vacuum forming puppet eyes? 

Check your local craft store in the area where they sell wood shapes and see if they have 1/2 wood balls. I would say that would be a good base.

I regularly use vacuum forming for eyes and teeth and as Shawn suggested find lots of stuff in craft stores to use as patterns.  In particular plastic Christmas ornaments work great as a base since they either come in two halves or can be cut in half very easy.  Also acrylic cabochons work nicely as bases (Tap Plastics).

I don't use these items in the vacuum forming process because they would not stand the heat. What I do is make molds that I use to pull resin casts; the resin holds up to the heat of forming and is very durable.

Barry

Shunaka, how do you usually attach the vacuum formed eyes? I can get such eyes (small ones) cheaply here, but had problems attaching them.

I have a couple of methods I use depending on the type of head material.  Generally I trace out the base of the eye shell on a piece of scrap polystyrene and cut that out. I then glue the cutout to the shell with epoxy.  This gives me a nice wide base to glue the eye to the figure.  The only small downside I've found is this leaves a very thin line showing at the base of the eye;  from a distance though it's not noticeable. 

One can also glue tabs to the inside of the eye shells which are then poked though the fabric and secured- this works best with hard shelled heads.