How heavey is a poly hive?

[Poly Hive]

Some clarification would be useful given several of us have gone to some effort on the OP's behalf.

PH

 

[BeeJayBee]

So each cubic centimetre of high density polystyrene should, if the figures are correct, weigh 10g

Err, no.

You're right! What a darned stupid mistake

1m^3 = 10^6 cc., no problem
100kg = 10^5 g, fine

so 1cc weighs 10^5/10^6 = 0.1g, 10cc weighs 1g, 1,000cc weighs 100g.

I *think* that's correct. It looks like it agrees with RAB's first post in this thread.

 

[Into the lions den]

Mod Beekeeping:

National:

Floor = 1.6 Kg inc varroa tray and entrance reducer.

Brood box = 1.9 Kg

Super X 2 = 2.8 Kg

Roof = 1.3 Kg

= 7.6 Kg Dense. Dense. Dense!

That seems quite heavy. Must go and weigh some.

Mind you, the weight difference between the original Canada nuc boxes, with hard plastic trim, and the modern ones made without it (from the very same mould) is considerable. Hard plastic is actually pretty dense stuff and could account for the variation, and in practise in some places has been shown to give rise to cold spots in the hive. It presence will also skew any estimate of the density of the main material, making it seem to be more dense than it really is. Only way to be really sure is to strip off the plastic, and do an immersion test to determine the actual volume of polystyrene, and compare this to the mass.

Going above 100g/L, and there are some now I understand up as high as 140g/L, is not a benefit, as you are territory where the conductivity of the material increases in direct proportion to the density. No need to go above 100g/L for durability, and insulation value varies in inverse proportion to the density. Way off topic though.

 

[alanf]

That seems quite heavy.

Back of envelope sanity check: a side is half a metre square (more or less). If it were 40 mm thick that would be 10 litres or 1 Kg at 100g/litre. Six sides to a cube, 6 Kg. Add some mesh and harder edges.

Not claiming that this is accurate, I don't have a hive, tape measure or scales to hand but it sounds about right.

 

[local_beekeeper]

Thank you for all the answers to previous questions

 

[BBG]

That seems quite heavy. Must go and weigh some.

Mind you, the weight difference between the original Canada nuc boxes, with hard plastic trim, and the modern ones made without it (from the very same mould) is considerable. Hard plastic is actually pretty dense stuff and could account for the variation, and in practise in some places has been shown to give rise to cold spots in the hive. It presence will also skew any estimate of the density of the main material, making it seem to be more dense than it really is. Only way to be really sure is to strip off the plastic, and do an immersion test to determine the actual volume of polystyrene, and compare this to the mass.

Going above 100g/L, and there are some now I understand up as high as 140g/L, is not a benefit, as you are territory where the conductivity of the material increases in direct proportion to the density. No need to go above 100g/L for durability, and insulation value varies in inverse proportion to the density. Way off topic though.

Two plastic runners per super/brood box - 2 plastic runners weigh 135gms - hardly worth considering ref cold spots at each end of the super unless the coefficient of brass figures in a beekeeper's life! - but well worth the protection element.

"Stripping off the plastic" only serves to reduce weight NOT the density of the polystyrene which IS rated at:

"The body material in our BeeBox hive system is especially hardened EPS polystyrene (density over 100 Kg/ m3)." On Mod Beekeeping site.

Is the "immersion test" a Eureka!! thing

 

[Into the lions den]

"Stripping off the plastic" only serves to reduce weight NOT the density of the polystyrene which IS rated at:

Of course..............only point is it is hard to check the density accurately while the hard plastic is attached.

And it really really is not needed.........not sure what yours look like but have seen them with the entire rebate area replaced with hard yellow plastic, and those I would not touch with a bargepole. Not sure whose they were.

Have thousands and thousands of these boxes in service, and NONE have any serious hive tool damage, and are worked hard by often semi skilled staff in a hurry. The so called extra protection is a complete non issue. Solves an apparently obvious problem that actually does not truly exist.

Breakages and other damage only happens when boxes get dropped, and the plastic edges will not stop that happening, except in the rare instance of a heavy object being dropped on the rebate area. Then you have a point, but this has never happened in our outfit even once, apart from one time vandals decided to knock the lid off and chuck rocks (well smashed up concrete slabs actually, they dismantled the pathway in an adjacent garden for ammunition)at the exposed hive interior.

 

[For want of a better word]

Is the "immersion test" a Eureka!! thing


Confusing differences between the displacement and actual weight like in ships....
but I think specific gravity comes in somewhere?
weight in air ... weight in water.. volume...
Can I go and lie down now!

 

[BBG]

Into the lions den

".only point is it is hard to check the density accurately while the hard plastic is attached."

As said, it comes off.

And is not on all four side of brood or super so a check in that fashion, if you have the time, and accuracy, if needed, is simple.

I was in the Fourth Form I believe when we did it.

I imagine having the plastic protection to put on and assembly for so many thousands and thousands, would be very labour intensive and expensive; off-putting to a big concern.

Also buying in bulk for own use, or to sell on, would bring the cost down to levels where even a shorter lifespan would not be an issue. For a big concern that would wish to reinvest, rather than pay more tax that is.

 

[Finman]

Into the lions den

".only point is it is hard to check the density accurately while the hard plastic is attached."

As said, ... if needed, is simple.
.

it is simple. If bees chew themselves through the wall, it is not dence. If they do not, it is dence.

 

[BBG]

it is simple. If bees chew themselves through the wall, it is not dence. If they do not, it is dence.

V good!