I’ve since converted all of my fabulously patented ventilation rims into moisture quilts. See the updates at the end for more details. And of course I’m joking about the trademark… and the patent.
I made some improvements to the design of my ventilation rim (also known as a ventilation eke; also known as a vent box; also known as a whole bunch of other things because beekeepers are the worst for settling on a single name for one thing). It’s still cheap and easy to make and should do a fine job at improving the ventilation of any Langstroth-type hive. First, I cut four pieces of wood for the front, back and sides of the rim. Here’s a shot of the side pieces:
Here’s a shot of the front and back pieces:
All the measurements are written on the wood — in both Metric and Imperial. The red line on the wood indicates how far a typical telescoping top cover will hang down over the rim. The ventilation holes are subsequently drilled below that line so the telescoping cover doesn’t block the holes. I happen to have a 1.5-inch drill bit, but 2-inch-wide holes would probably work too; even 1-inch-wide holes.
Notice that the holes are drilled at an angle to minimize the chances of sideways rain from getting in. Here’s a straight on close up of one of the holes that sort of illustrates the angle of the hole (the hole from the outside is angled up so rain is less likely to drip down into the hive; at least that was my thinking when I nearly tore a finger off while trying to drill into the wood at an angle):
(I’d say that holes drilled straight in are fine for the carpentry ill-inclined. I have several prototype rims with holes drilled straight in and it’s not the end of the world.)
I stapled on some screen or mesh behind each hole. I don’t know the size of the holes in the screen. I assume it doesn’t matter as long as wind can blow through and predatory insects like wasps can’t get in.
So I took those pieces of wood and stuck them together with 2-inch-long brass screws, pre-drilling the holes first with a thin drill bit. I probably could have used a hammer and nails instead if I knew how to swing a hammer without hitting my thumb. Note that the front and back pieces go between the side pieces.
Also note that the front of the rim doesn’t have any holes drilled in it.
That’s because sometimes bees returning will try entering through any hole they can find, especially if the hole is near the top entrance. But when the hole has a screen on the other side, they can’t always figure out what to do and they just sit there trying to get in until they die. At the very least, it’s a waste of time for the bees when they get confused by a hole that doesn’t lead into the hive. That’s why I don’t drill holes in the front. (I suppose stapling screen to the outside of the rims would prevent the bees from even trying to go through any of the holes, but that probably wouldn’t have the slick professional look that we’re going for here because, you know, I’m such a professional.)
I don’t remember the cost of the lumber, but it wasn’t much, maybe $10 tops. The brass screws were cheap, too, because I bought them from a wholesaler. I didn’t use any fancy tools to make the rim. A hand-held jig saw, a power drill (which can double as a power screwdriver for anyone on a budget), and a cheap power screwdriver. I didn’t use carpenter’s glue, though I probably should have. Then there’s the screen which cost about $5 for a 20-foot roll, something like that.
I used a deep super to figure out the dimensions. I used the deep as a workbench, too, for the drilling and the sawing. I didn’t use a T-square or anything like that to ensure right-angles. It might be a little rough around the edges, but as far as I can tell, the rim works.
One aspect of the design I was careful about was making sure it was flat on the bottom. If one side happened to be even a fraction of an inch higher than the other sides (in the Metric System I’m talking about a millimetre) it could leave enough space for rain to seep in. I can’t think of anything else to say about it. Hopefully I’m not overlooking some glaring flaw in the design. Here’s the rim ventilating away on one of my nucs.
Placed on top of the inner cover, the holes in the rim should provide adequate ventilation in the summer to reduce moisture in the hive, thus accelerating the honey curing process when honey supers are installed. The added ventilation also makes it easier for the bees to regulate the temperature of the hive for brood rearing. The rim is high enough so that the lip of the telescoping top cover doesn’t block the holes, and the holes are angled down so rain is less likely to get in. I’m still new at this beekeeping game, but it looks like a well designed ventilation aid to me.
November 2018 Comment: My design of this ventilation rim was a stroke of genius. How did I manage to come up with something so useful so early in the game? I use these rims, or a variation of them, on all of my hives throughout the year.
In the summer, I use them as ventilation aids and they work beautifully. The bees in most of my hives don’t have to waste their energy fanning outside the hive entrance to cure honey, because the ventilation rims are already doing the job for them.
In the winter, I convert the ventilation rims to moisture quilts and they keep my bees warm and dry all winter long. I know ventilation boxes derived from the D.E. Hive follow the same concept and are probably more convenient because you just put them on and you’re done for the whole year, but I nevertheless marvel at my brain’s ability to work this out in the absence of any real life experience or knowledge of such a device. Way to go brain!
P.S.: Check out this comment from Rusty Burlew for a detailed explanation of hive ventilation (reproduced in a full post on her website: Physics for beekeepers: How does ventilation increase honey production?).
January 15th, 2014: This ventilation rim can be converted into a winter moisture quilt by stapling fabric or mesh / screen across the bottom and then filling it up half way with wood chips. I stole the moisture quilt idea from Honey Bee Suite. The ones I make are slightly different but have the same effect.
April 8th, 2014: I have to remember to paint the outside of any rims I make for now on. Moisture in the form of wind-driven rain or fog will easily seep into the hive if the rims aren’t painted.
February 2019 Postscript: I still don’t know how I managed to come up with such a simple design for something that works so well. Even drilling the holes at an angle — I think I came up with that idea two seconds before I was about to drill the first hole. (That’s the story I’m sticking with for now anyway because I so rarely luck into anything that makes me look smart.) These rims, exactly as I’ve built them, are now sold commercially as “vent boxes,” usually as the bottom half of the D.E. Hive ventilation system, which appears to be a ventilation rim with another larger box with more ventilation holes sitting on top of the rim. Here’s an example:
The expense of upgrading all my hives to the D.E. Hive design shuts the door on me ever going with the full D.E. Hive design. But I’d be tempted to go with them if I was just starting out.
Two more notes before I say goodbye: I don’t add ventilation rims to my hives when they’re nucs. I don’t think ventilation is a problem in a single deep hive as long as there’s a top entrance. I’d rather keep the heat in, instead of ventilating it out, to keep the brood warm while the colony is building up from a nuc. I install the ventilation rim once I add a second deep to the hive.
Although I have used these ventilation rims in the winter as moisture quilts (after stapling screen underneath), I don’t do it as religiously as I used to because my hives don’t get as damp in the wintertime since I moved to a different part of the island. These days, my winter preparations consist of installing a piece of hard insulation over the inner cover and adding a rim underneath to make room for emergency sugar feeding. It’s easier than dumping wood chips into a moisture quilt. If I notice dampness inside any of the hives, then I’ll add the moisture quilt.