As promised, my first incubator

[Stockwell]

Hi Ryan and Trev
Ryan, yes my incubators as you know are all constructed of plywood, and are in the 3 to 4 cubic foot range.
I only use a maxium of 4 1/8 inch soldering iron holes in each egg box... usually one in each corner of the lid.

Trev
Yes, Heat tape is what I currently use in all my incubators. It has the advantage of
distributing the heat very evenly, and this is actually an improvement over most other heat sources. Even without fans, there are no major hot spots in incubators using heat tape.. Fans of course mix the air constantly, and makes hot spots a complete non issue. It's critical to use low power low RPM fans, otherwise they will contribute to heating the box, and standard Radio Shack type computer fans move too much air.... Fans around 5 watt moving a mere 18 to 30 CFM is best.

You can screw the heat tape to a board, or silicone it to a piece of plexiglass.
I recommend elevating it slightly off the bottom just in case some water does end up in there...you don’t want your heat tape or any connection to it, sitting in water...

Just keep in mind you need only 5-10 watts of heat per cubic foot of incubator volume, in order to raise the temps 20F above ambient.(70 room temp to a max of 90 for pythons=20F)

A 30 watt element such as those in the hovabators is actually a little more power than is really required for our use with herp eggs.... You must remember that hovabator elements are for chicken eggs which are hatched just under 100F, so they must elevate ambient by 30 degrees F where we generally need less than a 20 degree rise

20 watts would be loads for a typical fish size styro.... Using 4 inch 8 watt heat tape, that would be 2 and a half feet......Should be no problem.I'd start with 2 one foot long pieces and lay them side by side the full width of the bottom... I think 16 watts would do it...

If you're using a big camping cooler or other wooden enclosure, then simply determine the cubic feet volume(LxWxH) in inches,divide by 1728 and do the math to figure out how many feet of heat tape you will need....10 watts per cubic feet of air, is easy to remember. In most cases, a little less will actually be fine.
The way to test for this is set the unit up, and see how long it takes to reach 90F from a room temp of 70F
If it runs longer than 20 minutes before reaching setpoint, you better add another strip of heat tape..(this is my personal test criteria with wooden boxes with sliding doors)

Also worth stating, is that too much power will cause the temp to increase very rapidly and over shoot your setpoint causing wide swings in temperature.
You want to avoid that… and must remember it takes time for everything to heat up and it takes time for the metal in the thermostat to respond…

Have fun building!!