The Beekeeper’s Companion Since 1861
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Beekeeping Basics

Using Wax to Preserve Woodenware

- December 1, 2020 - Meghan Milbrath - (excerpt)

beekeeping woodenware

Ever notice that the word “pain” is in “painting”? While I love bees and beekeeping, I hate painting boxes. My sideline operation in Michigan is limited by both space and time, and paint needs both to dry. Since I operate out of a small shared building, and Michigan weather is not always reliable for drying paint outside, a few years ago I looked into alternatives to painting boxes as a method of woodenware preservation. I tried paraffin wax preservation, and I have never looked back. The process is quick, it does not require space for drying, and the boxes last much longer than those done with paint or stain. Even better, a hot wax system can sterilize equipment — including American foulbrood (AFB) spores, and I love reducing disease risk any way that I can. In this article I have tried to outline my experience so you can see if this is something that might work for you and your operation.

The whole process occurs by dipping woodenware in a tank of hot wax. The tank is basically a large stainless steel rectangle with a removable lid. Mine is big enough to dip six deep boxes at a time (two stacks of two side-by-side with one in the middle of each stack), though I’ve seen others that are much smaller. The nice thing about having such a large tank is that is ultimately saves a lot of time — between loading, unloading, and a 10-minute dip, each batch takes about 15 minutes. If you double the size of the batch, you halve the time it takes to get through your woodenware. Of course, this is only useful if you plan on doing a lot of boxes. The downside to a large tank is that I had to purchase a LOT of wax to fill the tank — about 700 pounds.

I have always been able to find the wax, though it is not cheap because it is an in-between size order for most companies — more than used for crafts, but less than used in industrial applications. Often, the cost of shipping is about the same cost as the wax, so if you have the vehicle and time to pick it up it is likely worth your while. I’m lucky because there are two other beekeepers in the area that I can order with to share costs. It is also important to know what size pieces the wax will arrive in if you have to hand-unload like I do. While I can accept a freight shipment at the farm, I have to hand-move it around the garage, so I get 60-pound boxes that I can easily lift. I use a mixture of 2:1 ratio of paraffin and microcrystalline wax. I use this ratio because it is what most beekeepers use who dip their equipment (and write about it on the internet or answer my phone calls). I have not been able to find a lot of data or reasoning behind wax mixtures, but the current mix works fine, so I have not been motivated to mix it up. I do always talk to a dealer to check the specs, because it is really important to pay attention to the flash point and the melting point. You want a wax with a higher melting point, so that it will not get tacky and sticky in hot sun in the bee yard (this is why beeswax does not work). More importantly, you want to have a high flash point so that you don’t create a driveway disaster.

In order to sterilize boxes for AFB spores, you want wax that can be heated to 160° C (320° F). The wax also has to be hot because the process needs to be above the boiling temperature of water. Rather than coating the outside of the wood, the wax dip process boils the moisture out of the wood, and the wax is sucked inside. The hotter the wax, the faster this process occurs.

Becacause you are boiling water out of wood, the moisture of the wood is a very important consideration. When the woodenware is brand new, and often very wet, there will be a lot of moisture. Because we do it outside, we also have to watch the weather so the boxes are dry and we don’t get rain/moisture into the tank. Moisture will cause the wax to foam, and it can overflow. We learned this the hard way, and now also have an accidentially (and expensive) paraffin-sealed cement pad in our driveway. Now, we never fill the tank more than ⅔ with wax, to allow for the space of the wood and the wax, and our tank has a 2” baffle that drains into an overflow bucket. If I were to make a new tank, I would make a much larger overflow pipe to a bigger bucket, because when overflows happen, they are fast and dramatic.

Besides overflows, there is a lot of potential for fire. We minimize risk by keeping a fire extinguisher close by, keeping a clear space around the tank, and having a steel lid always accessible — it hooks to the side during use. Our bottom is flat, but in the beta version, I would have a lip that drops down to shield the burner from drips. Our tank is on casters, so it can be rolled out of the garage to an outdoor, open cement pad for dipping. If you had a forklift, I would just leave pallet jack openings rather than the casters in the design. If you do get casters, I would make sure they are metal — speaking from experience, if you have composite casters, and it is a cold windy day so you insulate around the bottom of the tank too well, you will melt your casters to the cement pad, and have a real fun afternoon trying to move an 800-pound tank that is melted to your driveway.

Our tank is not insulated, so on very cold days it is hard to keep the wax up to temperature. One very cold and very windy day we were using a ton of propane, and would have to take breaks between rounds to bring the wax back up to temp. Our solution was to insulate with rockwool and cement board. Those are both safe to use, and non-flammable. However, what we missed was that if there was an overflow, the insulation would keep the wax right next to the tank. It dripped down the side of the tank and onto the casters, causing them to burn. We chose to learn through experience, but you could use foresight if you like — either insulate the tank more safely, only dip on hot days, or assume that everything nearby is fair game for starting on fire, and purchase metal casters accordingly.

Our tank is heated underneath with a black pipe burner (from a meat smoker/grill company) with an adjustable regulator hooked to a 100-pound propane tank. I have seen photos of some people who heat their tank with an open fire. I believe this to be dangerous because the wax is so flammable and the flame cannot be …