Linseed Oil Hive Sealant Experiment

I recently made two new super boxes in preparations for the spring. They're both standard Langstroth "medium" supers, nothing fancy.

I did decide to experiment with something I've always wanted to try: sealing the wooden hive body with wax and linseed oil. 

I've always read about how "natural" this can be (assuming you don't have linseed oil made with heavy metals) since the oil will seep into the grain of the wood and seal it from moisture. It's also supposed to be better than traditional paint because it doesn't off-gas toxic fumes* while it's drying (or for the period of days after it's "dried" like latex paint does.  

Ah, you noticed that asterix (*) in the last sentence? We'll get to that, but first I need to share with you what Linseed Oil is and what it's made from.

Linseed Oil, as explained to me by WikiPedia is a "colorless (or yellowish) oil obtained from the dried, ripened seeds of the flax plant by method of pressing [squeezing] the plant, sometimes followed by solvent extraction."

The article goes on to state: "Liquid water penetrates a linseed oil finish in mere minutes, and water vapour bypasses it almost completely.[5] Garden furniture treated with linseed oil may develop mildew. Oiled wood may be yellowish and is likely to darken with age." 

Wait, what? Having read those last few sentences, now makes me want to scrape down the linseed oil and just paint the hive body. Sheesh. Where was all this information in the bee books that praised the oil?

Oh, we still haven't covered what the asterix was for have we? The linseed oil is a plant based oil, and when applied warm/hot  (per the directions of bee books to make sure it penetrates the wood) it has a terribly strong vegetable smell. The kids and I were immediately put off by the smell.  Hours later my wife came home, and even she who loves vegetables of all varieties, asked "what is that awful smell and [how long will it last]?"

It is hard to describe the flavor of aroma that burn into my nostrils, even now, but try to imagine green beans, mixed with peas and asparagus boiled down to a super concentrated solution and then vaporized all around the room. If you can imagine that, you're about half way there to the actual smell.

Having to smell the stuff as I was putting in on the box, I declared that I would finish the experiment on one of the boxes, and would paint my other box in a more traditional (my traditional) white latex paint.

I should mention that I mixed the oil with bees wax from the hives in an approximate 10:1 ratio of oil to wax. I used 9 ounces of oil and 1 ounce of bees wax and heated in a double boiler until the wax was melted. 

After giving the box 20 minutes to "soak in" whatever it was going to soak, I wiped the excess standing oil/wax from the boxes since the directions on the oil said that any standing oil should be wiped, else it would create a very sticky residue.

Once the excess was wiped off, the boxes turned from a dark yellow to a lighter shade of yellow and started to look really nice.

A day later, I checked again, and the smell was completely gone and the boxes looked great! 

The end grains of the wood soaked in a little more oil/wax, but that was an advertised behavior the oil can said would happen (unlike how they didn't prepare my nose for the smell).

In the picture above, the top box was treated and dried, the bottom box still awaits it's paint ('cause it isn't getting the oil treatment!)

I'm not entirely sure how well the oil/wax will hold up to a season of sun and rain, or how much protection it will provide against wood rot, but I suppose I'll leave it as is and report back how well it does (or doesn't do) at the end of the season.

Feel free to leave a comment to raise my spirits (and expectations) of how well this may go if you've used linseed oil and wax to seal any hive boxes, and have had good results.

Comments For This Post: (4) | Post Your Comments! Hide The Comment Form
Robin Edmundson says...
Date:   February 17, 2016, 7:13 am

Great experiment!   How did you decide on the 10/1 ratio?    Still laughing about the smell description.   Eww. 

I asked my husband what he knew about linseed oil and he said he'd tried it,  it was just OK, not great.   The real danger is with the rags.   He had some used rags sitting partially SUBMERGED in a bucket of water and they still started smoking.   Burn your rags immediately. 

Chris (Show Me The Honey) says...
Date:   February 19, 2016, 1:40 pm

The ratio of oil to wax was a guess, I saw that ratio somewhere on a wood working forum a while back. :)

I had heard about rags with linseed oil on them spontaneously combusting. The oil container said as the oil dries, that it heats up. I took my rags outside and burnt them right away.

Rob says...
Date:   October 25, 2017, 7:06 am

Hi Chris, 

I was just getting ready to treat 3 hive boxes with Boiled Linseed Oil and thought I should do some googling... I found your experiment and am wondering if you did an update or if you wouldn't mind telling the world how they look after a year.


Chris (Show Me The Honey) says...
Date:   November 2, 2017, 4:13 pm

I don't have any pictures on my at the moment, but honestly they don't look any different after a year of use in the sun, rain, heat, etc..

In fact, I like the look so much (natural wood grain) I may never paint hives again. There was no mold, no rot, no decay, and they look great. I'm not going to do any prep work at all between now and next year on these boxes, they're ready to go another season!

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