Step by step instructions for building a lizard incubator like mine.
I have read online many times the sad experience of a failed incubator for lizard eggs. Many of the more popular and affordable reptile incubators are either unreliable and often fail before even a year of use, or they are so small that only a few eggs can be incubated within. Inexpensive Styrofoam poultry incubators are also popular for incubating lizard eggs, but have a very small capacity, and are not very precise- especially if they are used in a room that is subject to temperature fluctuations when the seasons are changing.
Over the years I have used a variety of incubators and tried different methods and I have come up with the lizard incubators that I explain how to build here. They have proven reliable and precise. My lizard incubators have a temperature variance of +/- one tenth of a degree f at all locations throughout the interior of the incubator. And temperature fluctuation is also 1/10th of a degree during incubation. The controller can be programmed for a night temperature drop, and has safety measures in place should things malfunction to help protect the eggs within the incubator itself. More on that in a moment.
First- the standard caution when working with electricity. My incubators have worked very safely and well for me, and I have found them very easy to build and use, but I am not you. If you want to be safe and sure, you should hire an electrician to connect your wiring and you should test your incubator thoroughly before using with real lizard eggs. By building and using an incubator according to these instructions, you agree that I cannot be responsible if you make a mistake and burn your house down, or if you shock yourself and stop your heart when hooking things up, or if you throw a wild party to celebrate your incubator when your first lizard eggs successfully hatch and end up incurring a fine for disturbing the peace. In short, while these incubators have worked really well for me, I have no way to compensate for stupidity on your part. If you aren’t sure and don’t want to be responsible, hire an electrician to help you with this project. That said, it isn’t rocket science.
OK, so, with that out of the way, my philosophy on incubation is that when I have many eggs it is best not to put all my eggs into one basket so to speak. I have lived through the terrible experience of an incubator failing several years ago. I awoke one fine morning, happy because I had a big incubator with hundreds of eggs within- a pretty large percentage being fairly expensive lizards too. The reward of several years of hard work, study, trial and error and patience and breeding over generations. Going in to check on the eggs that morning, I discovered to my great dismay that the thermostat had failed during the night and the temperature within the incubator was 120 degrees. Cooked all the eggs. Was a terrible day. Whenever I see other breeders online using huge cabinets or closets with a thermostat to incubate their eggs, I think about my experience.
At the other side of that consideration though, is the fact that too small of an incubator really becomes limiting as well. So I wanted something in between. My incubators using my current sized containers for the eggs are holding 16 clutches of bearded dragon eggs each. Using this season’s average clutch size, that is roughly 346 eggs. I have used smaller containers in the past, and smaller containers are especially fine for smaller eggs (like jewelled lacertas, collard lizards, etc) and then even more eggs can be incubated per incubator. I like the size of the containers I am using though. I can put an entire clutch of bearded dragon eggs within- even my largest (largest ever for me was 39 eggs- average is 21, but I get a number of clutches that exceed 30 each season) and there is quite a bit of air space above the eggs, which is thought to be beneficial.
My other philosophy is that I want the thermostatic controller to be as accurate and reliable and safe as possible. The controller I chose has an audible alarm if the temperature goes beyond my specified range and shuts off the heat if a sensor or the controller itself fails- which should prevent my previous nightmare experience. I feel this controller is the best on the market.
How to build the Lizard Incubator
Supplies, where to obtain them and approximate costs at this time:
1 Spyder Robotics Herpstat controller. Mine are the Herpstat PRO, which has been discontinued in favor of an updated/upgraded model, the Herpstat 4. It can control up to 4 incubators at once. If you don’t need that, you may want a simpler/cheaper model. But the pro or 4 still has some nice features for example, it uses breakers instead of fuses. The cheapest model is $99 and can only control one incubator. The 4 is $339, but controls up to 4 incubators (or vivariums or combination thereof – these have nice features for vivarium control as well) making the cost per incubator less if you have multiple incubators – often a necessity if you are breeding more than one species of lizard as different species require different temperatures. These can be purchased directly from Spyder Robotics website.
1 23.75 in x 47.75 in White louver (Plaskolite). Also known as “egg crate”. Available at Lowe’s here. $13.97
1 little giant poultry incubator heating element. I buy the whole incubator from Tractor Supply Company here for $35 and remove the element and use the wires and nuts. Just unscrew all the screws you can see on top of the incubator, then unscrew the electrical nuts inside and remove the element and the wire running to the plug. Save the nuts to re-use in a few minutes. I prefer these heat elements because I have found them to work well and last many years. I also like how the mounts keep the element from touching anything that could melt or catch fire if the element overheats.
1 4″ 12VDC cooling Fan from Radio Shack here for $20.49.
1 Enercell AC-to-DC Power Adapter. Also from Radio Shack. $21.99. I suggest you find someone who knows what they are talking about and get a recommendation on what size to get. I’ve gone to 2 different Radio Shacks in my area and had 5 people help me select which one to get over the past few years when I’ve needed new incubators. I’ve had different recommendations on which adaptor is correct for the fan each time, and several employees that have no idea and say so. One employee didn’t even know the fan and adaptor could be connected and was pretty skeptical when I told him I’d done it several times already. I’ve been extremely disappointed by the lack of electrical knowledge Radio Shack employees have known. Seems like for an electronics supply store with lots of stuff for tinkering, electronic tinkering employees would be the norm, but at least in my area, the employees don’t really know much along those lines. The employee who explained to me how to use this adaptor was an electrical student at the time and I’m linking to the exact adaptor that he recommended here. These have worked fine for me for the past few years, but the specs don’t exactly line up with the specs on the fan box. 1 other (different model) adaptor I have makes the fan run slightly warm- not a big deal but enough to warm the incubator slightly on warm days in the summer compared to the ones the guy recommended. Another model I have seems to be working fine but only has a 300mA output rather than 1A like the model I linked to. If anyone knows what they are talking about or finds someone who does and can get back to me with a brief explanation about which model is best, I’d love to hear from you. Until then the 1A model I linked to is the one the electrical student recommended and has been working fine for a few years.
1 Coleman Xtreme 150 Qt cooler. Holds 223 cans and stores ice up to 5 days at 90 F. This is available at Walmart here. $69. You will probably need to order online, but shipping to your local store for pickup is free. They had nice blue ones, but at the time I am writing this they are out of stock online. Green or blue- same size and dimensions, no problem. This is a nice size for the size of egg boxes that I prefer. Other sizes will work, but will limit the box dimensions you can use for the eggs and limit the number of eggs you can get into the incubator itself. I got a couple of 120 qt coolers when I was making incubators and the local store was out of stock. I wish I hadn’t now because I can only get half as many egg boxes of the dimensions I prefer into the 120 qt compared to the 150. The Coleman brand has larger interior width than igloo which again, is necessary if you want to use the same size egg boxes inside. The temperature inside the incubator will be more stable because coolers are heavily insulated, especially 5 day coolers. It also means lower demands on electricity to keep things warm.
A good surge protecting power strip. Spyder Robotics suggests using one that is rated to protect expensive TVs and electronics equipment rather than any old strip, because poorly designed ones will not prevent damage to the Herpstat controller.
Scissors, a pair of pliers, clear packing tape, 12 cardboard tubes from toilet paper and some sponge. Cost – you probably have around the house already.
It will take an hour or two to assemble and get set up. Calibration takes about 30 minutes or less depending on room temperature thanks to the excellent controller.
Lets get started!
This false bottom allows air to flow below the containers, across the heat element and up again, circulating air completely around containers for a very consistent temperature throughout the incubator.
This photo was meant to show the tiny “-” on the plastic beside the hole for the negative wire on the adaptor. Look carefully on your adaptor cord and you will see it near the end, next to the negative wire hole.
Place the fan on the sponge mounts and orient so the wires naturally point towards the drain hole in the cooler. Notice that only the corners where the blades of the fan are not located touch the sponge. The fan blade needs clear airflow to operate correctly. Run the adaptor wire through the drain hole and into the lizard incubator.
Tape securely to the lizard incubator floor so the wires cannot be pulled loose or get sucked into the fan or touch the heat element. Plug in and confirm that the fan runs and the wire connection is secure.
Next comes the probe for the controller. This is the sensor that reports the temperature back to the Herpstat. The wiring is thick enough that if you tie a simple knot with it to secure it to the egg crate as shown the probe will remain in the upright position off the crate. The other end of the wire, once again, is run out of the lizard incubator through the drain hole.
Now, all the wires are taped securely. The probe wire is taped to the floor beneath the probe, and then everything is taped along the way so they cannot touch the heat element and so they cannot come loose if someone walks along and trips over the cords running into the lizard incubator. Or if the cords are pulled against when moving the incubators- I stack mine so sometimes the cables are pulled on when stacking and unstacking to check eggs.
Similarly, I tape all the cords to the outside of the drain on the outside of the lizard incubator to prevent pull problems when moving the incubator, as well as to seal the incubator to keep the warm air inside.
Replace the egg crate and position things carefully so that none of the cardboard tubes touches the heat element and so none of the egg crate touches the walls of the lizard incubator or another piece of egg crate. This prevents vibration from the fan from bothering the eggs. The tubes are also placed so they distribute the weight of the egg boxes later. Avoid a teeter-totter effect from tubes being far away from the edges of the crate. But they don’t have to be right at the edge either. It doesn’t need to be precise to do the job well. I don’t secure my tubes, but maybe you might want to with a bit of tape if you feel the need. Mine have never had a problem unsecured.
Follow the Herpstat manual to program the Herpstat according to your needs. For most situations, entering a temperature and letting the rest do it’s thing automatically is fine. It is a very good idea to program the high and low alarms as well.
Next post I’ll show the egg boxes and explain how I set the eggs inside.