As promised, my first incubator

[Scales Zoo]

I thought I would post some pictures of the first incubator I built. I did so with much advice and guidance from Roy the incubator king. I have secured an old fridge for my next project – which should start soon, as I just sent this incubator to a friend who hopefully will be able to use it for some python eggs he hopes to have.

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Side profile of the incubator as it looks when it is in use with the expanding rack. It was made with Styrofoam fish boxes, the expanding rack was the same kind of styro box, with the bottom cut out. Much like the hovabators.


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Here we see the inside of the incubator without the expanding rack in place. The plastic grating is from a fluorescent light fixture.

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I removed the grating to get a better look the heating system. I used a 40-watt replacement heat element intended for hovabators, but I used it at the bottom of the incubator. It is held off of a piece of aluminium with stainless steel 3/8 tubing hangers. There are 1’’ square aluminium tubing pieces used to hold the grating.

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I used a small 120-volt fan. It was with Roy’s help that I found such a low flow fan meant for 120 ac. You can also see the thermostat. I used to think the thermostats wouldn’t work as well mounted in the vertical fashion, but Karel Bergman, someone else who’s brain I got to pick for incubator ideas, told me he had good luck doing it that way, and it has proven to maintain just as tight control as when mounted horizontally.

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This is how I mounted the thermostat. I drilled a hole through the styro box to accommodate the adjustment handle.

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I made brackets with aluminium to provide support. Without them, I think I would have accidentally hit the thermostat, and caused damage to the styro box. Also note the lock nut on the handle. On the aluminium, it holds the handle from turning very well.

I like these fans and know where to get them (Thanks Roy) The thermostat and heating element, along with other hovabotor replacement parts are available from Berry Hill in Ontario (Thanks Roy again). I got all parts in record time, they were sent out very promptly, and they were very reasonably priced.

Anyways, I got a dandy incubator that holds its temperature from fluctuating more than 1 degree F. In the months I have used it, it seems to drift very little. If it did drift, I would double check the temps with a different thermometer (I used a unit with an outdoor probe, as well as an outside thermometer inside of the incubator) – and increase or decrease the setting with the handle. I could bump it up .1 Degree F with a small adjustment, it was easy to not overshoot the bump.

It has been used very successfully for colubrid eggs in the past, and is may be subject to the python test in the near future.

I am going to experiment with other, larger designs (can use it to rear babies when not in use for eggs) – and will plan on posting pictures when I am complete. I may just go ice fishing instead.

Ryan

[BoidKeeper]

Looks like I found my next project. We'll have to talk about the bar fridge one too. I've got one here from University that is dieying to be striped down and converted. It still works fine but my prioraties have changed since the days of dorm life!
Cheers,
Trevor

[Scales Zoo]

The one thing I failed to mention in the above post was how I actually incubated the eggs.

For the colubrids, I used a small rubbermade container, filled with moist vermiculite. The rubbermade container had 8 small holes in it made with a soldering iron. I could fit 4 containers, each with a clutch of eggs, inside the incubator pictured. I was able to separate the eggs, and set them in the vermiculite. If they would have been stuck together, I may have used some moist sphagnum moss over the egg pile - or chanced that the humidity would have been adequate for the eggs on the top of the pile (which I think it would have been).

If I was going to incubate python eggs, what I would have done was to use a rubbermade container with maybe only 4 holes in it. I would have used a peice of that plastic grating inside of the rubbermade placed over either moist vermiculite, or just plain water, and set the eggs (usually stuck together) on top of the grating.

Ryan

[mykee]

Ryan, that's a brilliant design. I wish you the best of luck with it, and hopefully, you'll get a great hatch %!!

[Will]

I like that idea! I was gonna build one using water on the bottom and a aquarium heater in a Coleman cooler, but those styros are super cheap, AND you can always stack them for extra space. Do you think it would work with an aquarium heater and water on the bottom...? I would think so, but then again, I've never done this... :D

[JDouglas]

Was a lot of moisture lost from your egg chamber when you incubated your colubrid eggs? My guess would be that with 8 holes in it and with the fan running the vermiculite and the surface of the eggs would dry out?

[Scales Zoo]

Will - I know some people who use water and an aquarium heater, but I think it is better to use a glass jar or bottle with water and heater, than to have the whole bottom covered in water. The water vapor from evaporation would condense, or saturate on the sides, and it would rain. This might be o.k if the eggs are protected from becoming to wet.

Jaremy - the 8 holes were really small, I made them with a soldering iron. I never had to add any water to the egg containers, the moisture levels stayed very high. I would have used less holes if the holes were going to be larger.

Also, the fan, which is a very low flow fan, only runs when the heat element is on. Aw well, with the "capacity" from 4 or more egg containers filled with moist vermiculite, the thermostat doesn't call for the heat and fan frequently, and when it does, it doesn't stay on for long. The amount the box is insulated helps retain the heat provided, and the heat element stays warm, and continues to give off a bit of heat for a while after the thermostat shuts off (just like a burner on a stove).

Ryan

[Ron]

Last year I built an incubator by putting the water and the submersible aquarium heater directly in the styro container. It did create a lot of condensation but I had a piece of glass as the cover and only holes on the side of the egg container. I think if you used a large jar it would still create the condensation but the water would not return to the jar so you would probably have to fill the jar once in a while. The way I do it most of the water returns so there should be no need to add water.

[chamitch]

ic i use that ame fan for my chameleon. from radio shack eh?

also where did u find the hovabator parts?
thanks

[Scales Zoo]

The fans weren't bought at radio shack, I've got a number I could dig - I ordered them from Ontatio. The hovabator parts were bought from Berry Hill in Ontario.

Ryan

[JDouglas]

Ryan,
Sounds like you got it all tested and tweaked! Thats great that the fan only runs when the heat is on. I know what you are saying about the heat not running much. In my incubator it is also off most of the time. From the looks of it your design doesn't cost too much to make. Next year when I hopefully have a few more clutches I will try and make one of those. My brother can get me huge foam coolers that are 4 inches thickon all sides from a meat shop. They would work great I'd bet. What was the total cost to build this?

[chamitch]

oh thought it was teh same 120 v from the ole shack.

anyway how much did the heater unit cost? i know they charge like 85 CD for a hovabator but not nearly as slick a unit as that.

good work :) hope it bring lots to u in the new year

[Stockwell]

Ryan, thanks for the acknowledgements and congrats on your incubator... It's nice to see that something came from all those late night emails.:)

I sent Trevor out a "kit" today...He'll be the next one running a similar "Home Brew"

I actually wire my fans directly across line so they run all the time.
I find mixing the air all the time creates the best overall stability, because if the fan switches off with the heater, there is thermal inertia in the element that will continue to rise directly and produce a hot spot on the bottom of the egg containers... IF the fan is still running and stirring the air after the element is switched off, this will not happen.
This isn't super critical with deep vermiculite in your egg boxes as it dissipates the temporary hot spot, but you might try putting the fan directly across line, just to see if there is any improvement in performance.

Ron, will and J Douglas..
I'm tying to convince people not to use open water in any incubator design.
If you chose to use aquarium heaters in bottles as your heat reservoir, that is fine, but put a lid on the container to cover the top to keep the water vapour in the bottle...
You don't want all that water condensing in your box, as that just makes a big mess, creates a shock hazard and would rust the fan(if you had one)
Keep the moisture in the egg box where you need it, not in the general incubator box..keep that a dry controlled heated area only!

[Scales Zoo]

I always like to try things out, so instead of keeping the fan on all of the time, I think I will try to find find a delay off timer - and set it up so the fan runs for 5 or 10 minutes after the heat element is powered down.

I measure the temps inside of the egg container, and the high low difference is about 1 degree F. I wonder what it would do with a fan on all of the time?

Roy, with your fan running all of the time, is your incubator is larger than mine right? What kind of holes do you put in your colubrid containers?

The other thing I did not mention about my incubator: The way I built the aluminum bottom allows me to take the heat element, thermostat, and fan out of that incubator, and set the whole unit in a larger container. All I have to do is drill a hole for the thermostat - and I could set this unit in an old fridge in about 10 minutes. I didn't do it intentionally, but a friend of mine pointed that out - and of course, I took full credit for the idea!

Ryan

[BoidKeeper]

Can heat tape be used instead of the hovabator heat element?
Trevor

[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!!

[BoidKeeper]

Good stuff Roy.
Thanks,
Trevor

[Scales Zoo]

Roy, ever considered writing a book like "Tidbits of info learned in 25 years of herpetoculture, and I've lost the hair to prove it"

I'd read pages and pages of your general rambling - I've learned so much over the years stalking you on the internet.

I think I plan on trying heat tape in my next incubator. After reading what you have wrote, I'm suprised that the dead band (overshooting of temperatures) isn't more of a problem with my incubator and 40 watt heat element.

I'm guessing, that because I use a lot of wet vermiculite in the egg containers, and have used multiple egg containers in the past, it dampens the temperature overshoot in the container because of the inherent capacitance, and holds the temperatures more by fluke than by thoughtful design.

Anyone know people who use nightime temperature drops for incubating colubrid eggs? I know a few people doing it successfully for a few years, and they are firm beleivers that their hatch rate percentage has increased for it, and that the babies start feeding earlier since doing so. I don't have the guts to try it, but I won't argue their successes.

Ryan

[Will]

I think I'm gonna use the Heat Tape method, got tons of extra 4" stuff lying around anyways, may as well start using it up.

I have a question about the thermostat -- how do you decide where to attach the thermostat...? Top/bottom/middle...?

[Scales Zoo]

I'm not sure if it would have made much of a difference with my incubator.

I put the wafer thermostat near the middle (from top to bottom), put my thermometer probes in the egg containers, and then calibrated to the temperature I wanted (inside the egg container - before any eggs went in them) by increasing the setting on the thermostat.

Ryan

[Stockwell]

Thanks Ryan...
I guess I have written a book...the pages are just scattered around on various servers and in poor innocent herpers mailboxes(like yours) :)

[crocdoc]

I had a small fan, almost identical to the one pictured at the top of this thread, running all of the time in my incubator when I first set it up. Because the incubator was very well insulated the heat kept rising well above what I had the thermostat set for. It wasn't until I aimed a temp gun at the fan that I discovered the culprit. The fan itself gave off enough heat to raise the incubator temperature a few degrees C. When I put the fan on the thermostat line (so that it switched on and off) the temperature stabilised.

In my current incubator I am using a dimming thermostat, so the fan has been removed entirely.