This is the foam cooler. I got it at the grocery store. It is 24" x 15".
I made a shelf out of the small hardware cloth for the bottom, at least 1-2" off the bottom and a wire wall standing up.
The light bulb, heater thermostat and the fan will be behind the wall, so the hatchlings can't get to it.
Here is the light socket and water heater thermostat wire up to the power supply coming in.
The PC fan is hung on the wire wall using zip ties. I found a 9 volt power cord at Goodwill from an old tape recorder. You don't want a regular 110 power supply line. The fan will burn out.
I took a piece of glass from an extra photo frame I had lying around and laid it on the top and traced around it. This won't be the line you cut, you will mark another line at least 1/2" smaller. Cut it out on the inner line. You will be making a shelf for the glass to set in by cutting out half the thickness of the foam to the second line all the way around. Lay the glass in the ledge and seal the edges with some sealer. Let dry completely before using.
On the outside I cut a hole big enough to get my hand through to turn the eggs. I used a cork as a handle. This way you don't have to open the big top and let all the heat and humidity out. Cut it like you would cut the top of a pumpkin, sloped in. This way the square you cut out will fit back together tightly and not fall through to the inside.
You will also notice, I used a pencil to make a hole in the side to place a piece of rubber tubing in through the wall and down under the hardware cloth where a pan will be located to hold the water. I use a syringe to add water, no need to open bator.
In this pic, I have a large aluminum pan that I cut down the height to fit to hold the water. But I don't recommend aluminum anymore. Mine was a cheap one and after one hatch, mine developed holes in it. I couldn't believe it. So now I use a large plastic pan and cut the sides down on it. It doesn't rust and is easy to clean. Before you bend your wire down to make your shelf decide what the height of pan you have is. I wish I would have thought of it before I made the wire shelf. Trying to find something that large and only a inch tall was hard to find. I ended up cutting the sides down on a plastic dish pan.
This last pic is showing the long handle screw driver that I used to poke a hole in the top directly over the thermostat that is used to turn the little screw on the thermostat to adjust the temp up or down without opening the bator.
The only thing I didn't show is the vent holes that are on the ends of the bator. I have two on each end. If I need to I can plug one or more of them with a cork.