transparent/"glass" CB

[MandF]

At the moment we have the wooden beespaced CBs with feeding holes from T's.

Having briefly used our polynuc with perspex cover/CB I think I would like to use similar for our normal hives this season (when not feeding).

I would have thought buying a square of perspex from wickes or somewhere would be ok, but I wanted to find out what everyone else uses - if from a non-beekeeping supplier then the exact material & thickness (needs to be rigid enough to not droop in the middle and compromise beespace).

Thanks!

 

[Queens59]

Could you not take the perspex to a supplier and ask them to match and cut to the size you need?

I agree they are useful - I have loved my poly crownboard this winter and I might follow suit and change all mine...when I can persuade hubby that the expense is warranted!!

 

[itma]

I've got T's polycarbonate. Its framed to provide beespace (same each side). Overwinter I've had very little comb built on the 'glass'. No personal experience yet of cleaning. Supports a marge tub of fondant happily over the central feeder hole. Considering the small price difference between T's conventional board and their polycarb version, I'd say polycarb every time you might buy a cb from T's (not that that would necessarily be all that often!)


Pespex is cheaper than polycarb and even more prone to scratching. For the same thickness its also bendier.
Stiffness really starts to come into consideration if you plan to support any sort of feeding arrangement on the board itself (like a jar or small rapid feeder). One reason for making any frame double-sided is that after a while, you might want to use it the other way up occasionally to get it to sag back towards flat! (No sign of such need with T's product yet, but sagging would be more of a problem in warmer weather.)
Without a feedhole, the clear panel only needs to support its own weight ...

If you were making your own, you could add some short central support laths to rest on the frame top bars, to prevent sagging and maintain beespace even with a feeder on top.

Polycarbonate is used for some greenhouses and for anti-vandal glazing, so you might be able to get it cut exactly to your chosen size from glaziers and the like.
Apart from questions of ruggedness (and thus human safety) actual glass isn't as good a thermal insulator as these plastics.

I'm surprised how little the bees react to the clear cover being exposed and light flooding into the hive. My bees may be pretty laid back, but nevertheless I'm surprised just how little they react to someone "having a look" through the clear (edit) top board (as the Doc says, mustn't call it a cb, as there's a hole in it!).

 

[MandF]

I think the poly nuc sheet would be too thin and sag in the middle and/or be difficult to handle at full size?

 

[drstitson]

just use a sheet of polycarbonate without holes if on TBS. you'll get shouted at here if you refer to feeder/clearer boards as crownboards.

the ones supplied with polyhives are too floppy so go for a bit thicker.

 

[itma]

I think the poly nuc sheet would be too thin and sag in the middle and/or be difficult to handle at full size?

"Cover sheets" (thin, flexy and resting directly on the top bars) seem to be commonly used with poly hives.
A 'proper cb' needs something much thicker, like 5mm - no, I'm not opening up today to measure for you! (Sorry!)

 

[Kev]

I have a perspex CB, found the cheapest place was a local sign maker who also makes displays for show stands etc.
Needs to be 5mm thick to support some weight. I drilled small holes around the edge to be able to put a frame on it to provide the bee space. They cut it to size and cut a 50mm hole in the center for me. I have added a couple of small holes that take small (M3) machine screws near the center that rest on the frame to give some extra support.
The cost, 2 jars of honey

 

[MandF]

After doing a quick ebay search, the 4mm polycarb sheet below seems ideal. I might ask them for a quote to cut the sheet into 2 CB sizes for me, and send them, plus offcuts to me.

I could then form a frame the other side from the offcuts and be able to use it when apiguarding (3 x 4mm strips all round maybe)

ebay link

One could also, I guess, cut out some feed holes and sliding door/cover for feeding, but thats going a bit too far for me!

 

[itma]

Not too sure about Apigard, etc & these plastics ...

I've just used an unsecured small piece of thin and flexy plastic to cover the hole ... kept them away from the Kingspan insulation just fine. A sliding door is goldplating the design!

 

[MandF]

Not too sure about Apigard, etc & these plastics ...

I've just used an unsecured small piece of thin and flexy plastic to cover the hole ... kept them away from the Kingspan insulation just fine. A sliding door is goldplating the design!

Have you just got one feed hole? if so, how large? During the summer I use one of rapid feeders, I was considering copying the 2 oval feed holes, but actually 2 circular holes would be as good I think, and a LOT easier to cut out!

And I agree about the gold plating

 

[Monsieur Abeille]

Only advantage of the oval shape is if you want to use porter bee escapes.

 

[drstitson]

"kept them away from the Kingspan insulation just fine"

kingspan is foil covered - so why the need to shield from the bees?

 

[MandF]

I used some folded tin foil over my feed holes (on wooden CB) just to prevent them propolising the kingspan foil around the edges of the holes which might rip the foil when lifting it off.

If using polycarb CB I would prob use a sheet of perspex for that job.

 

[itma]

"kept them away from the Kingspan insulation just fine"

kingspan is foil covered - so why the need to shield from the bees?

Off topic but ... Insulation cut before installation to make room in the lower layer for a marge tub of fondant, so some foam exposed and a nice little cavity that I didn't want filled with wild comb. And yes, after the insulation went on, the ivy kept giving, and they did build some scraps of comb ... but not above the top (not crown) board

 

[user 6228]

depending on the material and thickness you may find it useful to sandwich the plastic between thin layers of mdf before cutting.

 

[drstitson]

"Insulation cut before installation to make room in the lower layer for a marge tub of fondant,"

you mean you didn't keep the cutout piece for use when no fondant in place. shame on you. think of all that vain space that the bees are having to heat!

 

[itma]

"Cover sheets" (thin, flexy and resting directly on the top bars) seem to be commonly used with poly hives.
A 'proper cb' needs something much thicker, like 5mm - no, I'm not opening up today to measure for you! (Sorry!)

The T****e's catalogue says that what I have is 3mm thick polycarbonate.
I do like the top beespace that the surrounding frame provides (on a std bottom beespace National).

I guess that an unframed sheet of 5mm perspex would work, but I suspect that there would be rather a lot of prop obscuring the view where it was stuck to the top bars. Unless your hive has top beespace already, a frame is a particularly good idea!

 

[parkranger]

poly crown boards

Having read this thread, have taken note of the important points such as thickness and the need of a frame for bbs nationals. Is there any problem with ventilation when using a polycarbonate crown board that does not have a feeder hole. If propolised around the edges I fear an airtight seal which must affect bees efforts to evaporate nectar.

 

[For want of a better word]

My ancient WBC hives have wood framed 2mm glass quilts with a round vent/feeder hole in center... I cover with a carpet tile or two.
Has 9mm bee space underneath.. replacement glass was a few pence from picture framers

 

[drstitson]

"Is there any problem with ventilation when using a polycarbonate crown board that does not have a feeder hole."

It's a FEEDER hole. Not a ventilation hole.

no ventilation needed up top if on OMF.

"If propolised around the edges I fear an airtight seal"

if really worried you could always invest in a set of commemorative sterling silver matchsticks from the BBKA website shop.

But seriously, aside from a few specific instances that ITLD has detailed wonderfully, extra ventilation not needed.