Expanded Cork for Long Hive?

[BeeSpace]

Afternoon all.

Thought I'd seek a bit of feedback on this idea so I can trap any pitfalls before I lay out any cash for materials.

I'd like to try making a long national for my kids to work (and because they interest me). It would take national brood frames (not 14 x 12). I currently run wooden nationals with a couple of poly nucs. Assuming some or all of them get through winter!

I was considering using expanded cork insulation to build the hive. I've confirmed with a supplier that it's okay for use outdoors. I'm thinking of 30mm thick cork, double walled so it's 60mm thick all round for insulation (top of roof 60mm too).

It'll have dividers to make up 3 x 11 frame brood or split into 5 x nucs, a mesh floor and I'll make a multi-part ply crownboard, plus an eke for feeding. Joints will be butt jointed at present - I can dovetail if necessary but I've only done it on a much smaller scale (think boxes for playing cards scale!) and feel there's less opportunity for mistakes if I keep it basic, although appreciate it's a weaker joint. I'm thinking wood glue and screws. Available tools are hand tools only (and thank god it won't need planing as that's a skill I really need to work on!)

Okay, be gentle folks, my beekeeping and woodworking are both at the beginning end of the spectrum...but fire away, all suggestions and advice welcome!

 

[For want of a better word]

Sounds like a fun item to make.. only comment is that the cork bungs ( Champagne corks) I use in my Top Bar hive get nibbled away... perhaps the bees like the remnants of a good vintage!

 

[JEP]

Cork is not ideal for that kind of construction. Its main problem is its lack of strength. You would be better off constructing the hive out of more traditional materials such as cedar, pine or exterior ply.

 

[Helen]

What about 2 thin sheets of wood/ply, sandwiching your cork? will stop the bees getting to it and add a bit if strength. or replace cork with celotex or suchlike?

 

[Hivemaker.]

or replace cork with celotex or suchlike?

... maybe with coconut matting.

 

[Newbeeneil]

I have been designing a hive similar to this based on a sandwich of 50mm Celotex between 5mm ply on the inside and 10mm cedar externally.
I wouldn't like to leave cork exposed as it tends to pick up algae in the rough surface. I remember having cork tiles back in the 70'S that went green after a yr outside.

 

[Murox]

Sandwiching cork with thin ply could be an answer, still relatively light weight and probably strong enough with wood glue and butt joints, keeping it all square might be a challenge.
Putting expense to one side for a moment - think SIPs panels - ply rather than OSB sandwiching an insulating material. Presumably it would not need to be moved much at all ? Good luck.

 

[Eyeman]

Maybe paint the cork?
Found this suggestion

Cork is extremely porous and needs to be sealed before you paint. Primer provides a base for the paint to adhere to but it won't fill the pores. Shellac fills the pores completely, leveling out the texture. ... Latex paint can be applied over either type of sealer to give cork a fresh, new look

 

[BeeSpace]

Sounds like a fun item to make.. only comment is that the cork bungs ( Champagne corks) I use in my Top Bar hive get nibbled away... perhaps the bees like the remnants of a good vintage!

I was wondering if they'd nibble the cork, so that's useful to know - thank you! I'll need to take that into account.

Cork is not ideal for that kind of construction. Its main problem is its lack of strength. You would be better off constructing the hive out of more traditional materials such as cedar, pine or exterior ply.

I've made a ply nuc but would like to try something a bit different as I find it a bit heavy; I don't have the woodworking skills to warrant using good cedar or pine, hence looking for something else. I'll take the strength issue on board though and look at ways of improving the design to mitigate.

What about 2 thin sheets of wood/ply, sandwiching your cork? will stop the bees getting to it and add a bit if strength. or replace cork with celotex or suchlike?

I have been designing a hive similar to this based on a sandwich of 50mm Celotex between 5mm ply on the inside and 10mm cedar externally.
I wouldn't like to leave cork exposed as it tends to pick up algae in the rough surface. I remember having cork tiles back in the 70'S that went green after a yr outside.

Sandwiching cork with thin ply could be an answer, still relatively light weight and probably strong enough with wood glue and butt joints, keeping it all square might be a challenge.
Putting expense to one side for a moment - think SIPs panels - ply rather than OSB sandwiching an insulating material. Presumably it would not need to be moved much at all ? Good luck.

Maybe paint the cork?

I like the idea of thin plywood covering the cork - the lamination will help the strength and will help avoid the algae / porosity issue; it just so happens that I was in B&Q today and found a couple of sheets in the offcut bin, so picked them up - gives me some options!

Thanks everyone; it's great to have some input as hopefully it'll minimise (but no doubt not erradicate!) the number of errors I make and problems I create! Actually, I suspect Murox got closest to my biggest problem - keeping it all square! Time to 'measure twice, cut once' as my grandad used to say

Will work out when I'll have time to build and look at getting something put together in the next couple of months.

 

[MartinL]

I was considering using expanded cork insulation

This may be a dumb question;

What is "expanded" cork??
I thought it grew on trees?

 

[Finman]

Look from internet, what they are selling.

 

[BeeSpace]

This may be a dumb question;

What is "expanded" cork??
I thought it grew on trees?

Not a dumb question at all - and yes, it does come from the cork they take off the trees.

It's agglomerated cork that is heated to high temperature; the heat causes the grains to expand, a bit like popcorn, and it releases a natural resin that binds it together. Great for insulation, acoustic dampening etc. I thought it sounded a bit like polystyrene, but more natural, so fancied having a play with some (although hopefully, sawing it doesn't make a sound like sawing polystyrene and leave my workshop looking like it's filled with artifical snow...!).