Wayne, here's what I used last year and had an 85% successful hatch rate with northern ringneck snake eggs.
20 quart rubbermaid container
Perlite
Water bowl
Heat pad
Moss
Ringneck snake eggs 
I put an inch of the perlite in the container, and spray it with water. I put moss around the corners and edges of the container and around the waterbowl. I put the waterbowl on the right side of the container and the eggs on the left side. I put the heat pad under the right side, right under the water bowl. I didn't put any holes in the lid, I simply took the lid off once or twice a week to let the container air out. I had a few bad eggs, but other than that, all good!
With turtles I did the same thing, except I buried 3/4 of the eggs in the perlite. That worked too.
Mike
Pic of last year's incubator when I used soil instead of perlite.

Michael's Place
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Helmz777@aol.com
www.freewebs.com/mikesnake
