Skull with Straws	Inside Skull Mold	Side View of Skull Mold	Front View Skull Mold

Using Fix-all or any other plaster medium and a small, cheapo skull from Party City, I made skull plaques that have LED eyes.  This particular skull was the shrunken head with the strand of hair used for a hanger.

The picture on the far left is of the inexpensive skull that originally came as a shrunken head with hair.  I removed the hair and carefully cut along the seam line dividing the skull in half.  I cut a straw into two sections that would extend past the fix-all plaster in the mold and would prevent the plaster from exiting from the eye holes.  I used a drill to make the holes in the eye socket and made a tight fit for the straws.  The middle left picture is of the back of the mold with the straws already inserted.  One of the advantages of the straws is that they actually supported the mold in a level position and the fix-all would be at an even depth for the plaque.  The middle right picture is of the mold on a glass from the side.
I had to do a trial and error on the amount of fix-all to keep the plaques all the same size and thickness.  I ended up using half a cup of fix-all powder and a little over a quarter cup of water.  Believe me, just a small amount of water more or less will make a big difference.  The plaster sets up fairly quickly (that is why I used fix-all) so I made two plaques after work and one in the morning before I left for work.
Another modification to the plaques would be to insert a wire hanger on the back if you did not want to use these plaques in tombstones and pillars of pain like I did.  Also the battery pack for the LED eyes could be added to the back later when the plaster had begum to set up and additional fix-all poured around it to set it in place.
This is what the skull looks like after being removed from the mold and allowed to cure.  The picture on the right is of the skull after it has been inserted into the tombstone.  The back of this tombstone has an area cut out for the leds to be inserted and a place for the battery pack to be installed.
 

My problem now is that I look at everything as a mold.  I used the hard plastic wrap off of my dog's wind up toy mouse to make some snake heads (sorry no pictures yet).  I took 1 1/2" sections of pencils, sharpened them and inserted the pencils into the fixall/plaster when it was just beginning to set up.  I think I will use dowels of the same diameter next time because the pencil lead breaks when people play with them.