Wednesday, 23 February 2011

Making a Horizontal Top Bar Hive - part 4

Part 4 - Making your Top Bars
(Click here for Part 1 - Getting Started)

The top bars are really the key ingredient of a horizontal top bar hive - for the bees, they make up the roof of the hive. You will, of course, have a second outer roof to form a waterproof covering against the rain and sun, but to the bees the bars form the solid roof of the hive and replicate the top of the tree cavity they would be occupying in nature. The top bars should therefore be made of natural wood and no other man made material. You also need to be sure to your own satisfaction that the wood used is chemical and poison free – i.e. contains no treatments, insecticides or fungicides! Weathered wood is ideal.

I will mention in passing that some Top Bar Hive users are experimenting with curved bars or gapped bars with a Warre style hessian quilt covering which may, in time, give us more options. However, for the purpose of this guide which is written for those new to this style of beekeeping we will stick to the tried and tested design of straight top bars forming a solid roof.

What size should your bars be?
The length and depth of your bars is the easy part, but the width is crutial - see diagram aside.

The Length meeds to be long enough to span the width of your hive plus an overlap. If you are building to the Barefoot Beekeeper plans this guide follows this will be 17”, no longer or they won't fit between the front/back roof frame which we recommend. Click on any image to enlarge it.

Height is not particularly important but does need to be at least ¾” or 20mm. The thicker they are the more insulation they give but you can add insulation above by way of a Warré style quilt box, using wool carpet or other natural insulating material so I would suggest that thicker than 1½” starts to get impractical. The ¾“/20mm minimum ensures that the bars don't flex when lifted with a full comb of honey attached. Any flexing will cause new comb to break and the collapse into the hive – something you want to avoid.

The crucial measurement is the Width of the bars as the races of bees we have in the UK build combs that, together with their bee space, require a gap of between 32 to 36 mm – this varies as bees build different width of comb depending on where in the colony it is in relation to the brood nest and the time of year it is built.

I suggest that you make your top bars widths to one of the two ways as follows - though I'm sure that there are others methods:-

The All Bars Equal method
This way you make all your bars all the same width at approx 35mm each and rely on your starter strips, plus the occasional inspection to keep them lined up. Of course the bees don't read the manuals and therefore often don't play the game to our expectations so you will get some cross combing but you can either 'mange' this by breaking off  the ends of the comb and bending to correct it when you do your occasional inspection or by just live with some cross combing. 

The Adjustable Width method
This way cut your top bars at approx 32mm width but also cut matching 4mm spacer bars. You can then place the spacer bars between the top bars where the bees require more space and are starting to build comb between bars. This is certainly the more flexible approach and allows you to adjust your colony as it grows but the downside is that in order to do this you have to monitor their comb building closely and consequently you are more likely to open the hive more to check on progress and interfere with your bees more – not exactly sustainable/ethical bookkeeping practice!

Even if you use the All Bars Equal method it's always useful to have a couple of 4mm spacer bars to correct the gap if a run of comb gets out of sync with your bars.

The simplified method is certainly easier to make and probably will result in your interfering with your colony less. NB: If you want to really minimise your interference then you should consider converting to a Warré hive.

Once you have bars cut you then need to add some form of comb starter guide to try and get the bees to build on the bars. To do this see the next page.

© Robin Morris - YABeeP 

(Go to Part 5 - Adding comb guides to your top bars)

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