materials: styrofoam cooler / lamp switch dimmer cord from home depot / sand (playbox, washed) from home depot / digital thermometer / lamp kit for the light bulb / 40 watt clear bulb / small glass jar / small piece of glass or plexiglass / thick book
After placing the glass jar for water in the corner, I added 5" of sand in the styrofoam cooler. Make a 1/2 inch cut in the side of the styro wall to insert the cord from the light fixture in order for the lid of the box to fit on securely. Place the thermometer in the box as shown. Fill bottom with 5" of sand evenly. Make pencil holes in all sides of the box, and 3 in the top - to create air flow. Fill jar with water to about 2/3rds full.
Cut a 3" hole in the lid of the styrofoam cooler on which you will place the piece of glass or plexiglass. By adjusting the plexiglass cover for the hole you can fine tune the temperature in the incubator by a few degrees. Position the thermometer so you can view it through the lid opening. (plexiglass is covering the 3" hole).
Plug the light fixture into a lamp dimmer switch which will allow you to adjust the brightness (heat) of the bulb.
Once everything is in place turn the bulb on and adjust the dimmer switch to full brightness. With the lid on securely leave the lid hole open until the moisture that may be in the sand evaporates - about a day. When the inside temperature begins rising over 100 degrees begin adjusting down the brightness of the bulb in very slight increments. This turns down the heat. Once the heat inside stableizes cover the lid hole with the glass pane. Watch the temperature and adjust the brightness of the bulb as needed to maintain 99 to 100 degrees. Use a thick book to place under one end of the incubator and switch it 2 to 3 times a day from side to side. This will be the turning of the eggs all at one time without removing the top. The temperature will become stable and can be adjusted by sliding the glass pane to partially open the lid hole. Check occasionally that the water jar remains full. The sand in the box will become the stabilizer for the temperature in the incubator. In pencil add the date on the top of the eggs of when they are placed in the incubator. With your index finger make a small imprint in the sand and place the egg inside with the large end of the egg up. Holds around 24 - 40 serama eggs. After hatching the chicks, when dry, should be moved to a brooder which can be fashioned like the incubator.
For the brooder instead of using a styrofoam lid I use a glass top (that I leave open a few inches) so I can see the chicks. From the lamp dimmer switch I slowly decrease the light (heat) (using a red bulb) over time to acclimate them to the outside temperature.