Design Considerations

[rossman_2000]

I have been reading old posts in the topbar forum. In one old post from 2005 someone mentioned that they had built a top bar hive that had stright sides to the depth of a brood frame, then angled in towards the centre below that depth, with a 9.5" floor width. I looked around a little, but I didn't see any follow up on how well this design worked.

I have been thinking of doing a similar type design. My design will have 9" vertical walls, to take standard deep Langstroth style frames, and then the walls/floors will slope at 45 degrees to a 6" wide flat floor. This will give me a total potential comb height of 15". I will have 24 top bars that will be 19" long (the same length as Langstroth style frames). I want to be able to start the hive with a 5-frame nuc and then rotate out the frames once natural combs have been drawn out. I also want to get a little more depth to my brood nest so I won't have as many bars to worry about. I have calculated that the volume of this hive will be approximately the same as 3 standard deep supers.

Do you have any suggestions or comments on this design? Thanks.

-jason

[buckbee]

My feeling is that you will end up with comb that is too big and heavy to handle. Also, with that depth, I would bet that you will get no combs with only honey on them - the bees will put honey at the top of all combs and put brood below - making harvesting very difficult.

Every beekeeper is tempted to re-invent the hive. There is nothing wrong with experimenting, but there are a lot of TBH designs around that work pretty well. My suggestion would be to start with a proven design, try it for a while and then see in what way it could be improved.

[JaiPea]

Ditto on biobee's concern.

If you don't use frames it will be difficult to remove a comb that is partially braced to 9" of vertical and another 3-4" of diagonal. The heavier/larger the comb the more brace comb the bees build (even if the comb is hardened). Not only will the large comb be difficult to handle but you may never be able to change the configuration - they will only fit together with the correct bee space so long as they are not moved around.

Bees strengthen deep combs by building "waves" (same principle as pressing creases and ribs into sheet metal). Wavy combs will limit your ability to move combs between hives e.g. move a frame of brood from a strong hive to strengthen a weak hive or give a frame of newly laid eggs to a hive which has lost its queen.

The photo at http://tinyurl.com/2uzoef is of the lower half of a 15-18" deep comb that was being put into a removal frame. It came out of a wall and was straight at the top but about 7-9" down the bees began the wave, which became more pronounced the deeper the comb was.

> rotate out the frames once natural combs have been drawn out.

If you want to press ahead, recognize that bees draw natural comb in frames with starter strips and for a TBH you can shim the top bar to full width. The bottom bar becomes a 'top' that the bees can use to build comb in your angled section. The comb below will be short enough that there may be no waviness. http://tinyurl.com/36kje9 shows what a PF120 put in a deep looks like. This is small cell foundation and the bees get to draw natural cell comb in the bottom third.

Apart from exploring the unknown, what benefits do you feel the vertical/angled configuration will provide?

[rossman_2000]

Thanks for the suggestions.

I was kind of hoping to hear from BWrangler and/or MIKI because I'm pretty sure that they have both used bars that were wider than what I proposed and they have had comb that was deeper than my design. If you guys are reading this, do you have any comments or suggestions?

Just as a side note, the area where I live in northern New Hampshire never gets really hot in the summer and has very cold winters.

JaiPea, I was hoping that the bees would build comb on the bottom bars of the frames that I am starting with, just like the second photo that you posed. Once they do this and I put a top bar with a starter strip between two straight combs, won't they tend to build more straight comb instead of wavy comb like in your first photo?

Thanks again for all of your advice.

-jason

[JaiPea]

> JaiPea, I was hoping that the bees would build comb on
> the bottom bars of the frames that I am starting with,
> just like the second photo that you posed.

You cannot assume you will get straight comb below the bottom bars of the frames, which is why I suggested cutting a plastic frame to shape and screwing it under the bottom bars.

Even though that photo has seemingly straight comb it has waves when viewed from below as can be seen at (http://tinyurl.com/35cgvk). This frame was drawn between a pair of HSCs and half the length is just what you want, but the other half has a wave. This comb was drawn in the brood nest where bees are happy with a 1 1/4" spacing and the HSC is a little thicker than 1 3/8". This difference gave them slightly more than the minimum bee space and they used that to build a wave across half the frame.

> .....Once they do
> this and I put a top bar with a starter strip between
> two straight combs, won't they tend to build more straight
> comb instead of wavy comb like in your first photo?

With one caveat. When the top bar is wider than the width of comb the bees want to build they will have more than the minimum bee space, and they can introduce waves. If you go vertical for almost 10" (a deep is 9 5/8") any waves that are drawn will continue through the triangular bottom.

The narrowing width of a KTBH all the way down tends to reduce the severity of the waves.

> I was kind of hoping to hear from BWrangler and/or MIKI because
> I'm pretty sure that they have both used bars that were wider

You have two issues:

- the wider the bars, the more curvature you get across the bar.
- the deeper the TBH the more waves you get in the drawn comb.

As I recall, BWrangler's early KTBHs had sharper wall angles than his later designs which were more vertical, less wide, and less deep. He became somewhat disenchanted with wider/deeper/larger.

The further you get away from KISS the more guidance/assistance you have to give the bees and drawing straight comb is not a bee priority. The more convoluted the shape of the hive, the less likely the bees are to meet your goals.

My bet is that to succeed with the unusual shape and depth you want you will have to use frames but if you do proceed and it works well be sure to provide a photo record.