Let’s Design My Fridge Incubator

So I have like many others lost faith in the hovabator. I have never gotten over a 30% hatch and it’s time to move on. Hopefully some folks who have built before me can share some insight.

The starting unit is a full size side by side refrigerator. I already have the following in hand or in route:
1) The refrigerator
2) Herpstat 2 dual control proportional thermostat
3) (2) Brinsea Spot Check thermometers
4) 12” by 96” sheet of clear ¼ inch lexan (thinking door windows)
5) water wigglers or as they were labeled water snakes

Other specific items on my list
1) Ceramic heat emitters (light bulb types)
2) Misc light sockets, switches, etc

My first decision point is hatcher vs. incubator. For humidity and sanitary reasons, I know that I want to hatch outside of my incubation unit. This explains the dual herpstat. I know the larger previous fridge side of the unit will be the incubator. The other options are:
1) Let the entire freezer unit be the heating chamber with my bulbs. Pros: Fan is already configured to rotate air through that chamber and into fridge with minimal modifications. Cons: That’s wasting a lot of space for heating and I have to build or acquire a separate unit for hatching.
2) Divide the tops of each side (freezer and fridge) and create 2 heat chambers. Let the larger fridge side incubate and the freezer hatch. Pros: All one self contained unit. Cons: More complicated design for air flow, less space for eggs to incubate (I suspect still plenty to hatch given rotated setting dates).

Lets hear your thoughts!

Does it really need to be that big, also it will take a lot of heating to get it up to 37.5 due to the size. You will have to make sure that the pipes don't leak as dangerous gases may leak out them which would kill you and you chicks.

Drain coolant and remove compressor for weight consideration. I have never heard or read of anyone who ever regretted making their incubator too large!

Choose a side/top or bottom for incubator and the opposite top/bottom/side for hatcher. I would add fans in addition to what's already there. Install enough heat generation so that your thermostat kicks on for only a very few moments. Try to distribute/diffuse air (as in a louver) as best you can. Add heat sinks to assist you in maintaining even running temperatures. This will also help in the event of power outages.

Install internals in such a way that can be dismantled and cleaned easily. Ask me how I figured this out? I really like your glass idea. You might want to make it double panes for insulation. An egg turner is a HUGE help. Being able to add water from outside is helpful.

Hook up a switch to the fridge's internal light an "observation" light.

I like having my "stuff" such as heat elements, fans, water reservoir, ducts, behind a false wall. It makes it much easier to clean and, of course, it looks much neater. That's one reason I would choose one entire side for the stuff and the other side as hatcher and incubator combined.

You may want to send a PM to Quintinp for any specific questions you may have. He is about as knowledgeable as anyone here on building and wiring an incubator. I hope he answers your questions here so we can read them.

Best of luck with your build.

It’s been a while but I do have some progress. I decided to go with the big side as an incubator and the small side as a hatcher. I had the Freon removed and stripped all of the fridge stuff out. I cut a hole at the top for a 5” computer fan and built a duct from aluminum flashing to route the air from the top back to the bottom into what will be the heating chamber. I think I have my first problem. The fan came from a server and is much higher output than expected. It will actually pressurize and push the dents out of the flashing duct when on. I can diffuse the air at the bottom a bit before it re-enters the incubator from the soon to be built heat chamber, but I still suspect it will be a bit breezy in there. Will too much circulation be a problem? I have attached pictures of the fan, the duct, and the inside showing the fan at the top and the return at the bottom.

I sort of got forced on the issue. The seal of the duct (using some special polyethylene tape came all loose today so I took it all off. I have a smaller 4" fan in my collection that is much less "serious" at 12v and will run at 5v. I am going to re-do the duct with flex dryer vent and let it roll

I took some time off but have made lots of progress since last August but I have just got around to finishing. I did end up with an incubator side and a hatcher side. After a week of hatching I have some results.





Incubator Side:





Starting from the bottom the heat chamber has 2 light sockets. Currently one 150 watt ceramic bulb and one 250 watt infrared bulb. I started with 2 ceramics but we kept getting cold snaps (unit is in a garage with no door). The 2 ceramics were only stable to 38 or so degrees outside. I’m not sure what the limits are with the infrared but we have dipped to 30 degrees with no fluctuation. The heat chamber also has probably 40lbs of lead bars in it to make temp recovery easier when the door gets opened. There are multiple computer fans blowing out of the chamber and air is recovered from the top via a large server fan and ducted via insulated pipe to the heat chamber. I ended up needing more fans than expected to even out the temps from top to bottom. None of the fans blow directly on the eggs so any “breeziness” just goes around and up. Next I have 5 turner trays each with 88 egg capacity. The trays are turned via what used to be the motor that broke the ice cubes out of the ice maker. It is controlled by 2 timers. Timer A comes on and tilts the trays until it hits a stop switch cutting the power. A couple hours later Timer B fires and completes a motor revolution taking the trays to the stop switch on the other side. This took a few times to get right. I actually had to end up recreating the inside of the fridge on a workbench to build the turners and get the turning arm right. The temp is controlled via a Herpstat 2 (also has a 2nd circuit for hatching side). All of the fans are being driven by a power supply from a computer.




Hatcher Side:
The side has the same heating setup. The heat it not ducted outside the unit. I have decent sized fans at the top and bottom and the force air up and down the front and back avoiding direct egg contact. There are wire shelves to hold the hatching trays, water and sponges. I messed up a couple of the trays before settling on the cutout design. The trays also have removable raised wire floor allowing me to add watcher to the tray before adding eggs for more humidity. It hangs around 70% humidity (notice the foggy door). It also recovers very quickly when opened. I also think the water in each individual tray gives a little buffer for door opening.





Results:
I have been hatching for a week now. I added eggs as soon as I was remotely certain I could hold temps. I added eggs every day. This was cute for a couple of days but now daily hatchings takes up a bunch of time. I have over the last few weeks switched to adding every 5 to 7 days. My first few hatchings have been 50 – 60% each day. One day was 75%. I have not addressed humidity in the incubator side, I suspect it is too low. I weighed 15 or so of tonight’s batch of 86 put in to monitor weight loss.

What I learned not to do:

1. Put eggs in every day
2. Put your thermostat probe in a water snake. This created wide temp swings.

Nice incubator. I want to build one like this, but don't have a place to keep it, nor the eggs to put in it. I sold most of the chickens, and I am having to build up the young breeders again.

Heh, no, the thermometer can go into the wiggler, but not the thermostat!!! Looks good. I wish I had a sweet set up like that.

What would be easy to make one out of fridge. Or a Cabnet? ?