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Cork is quite a superb material and can be used as the middle sandwich layer with carbon fiber. It's also used in space launchers as heat and noise insulator in

Cork is quite a superb material and can be used as the middle sandwich layer with carbon fiber. It's also used in space launchers as heat and noise insulator inside nose fairings. It also has ablative properties and resists flame propagation. It's lighter than most other woods, though not as light as Balsa. So I think it's a bit of a shame that it's used for wine bottle corks and usually thrown away after use!

aeturnum 14y ago
Because cork is getting more expensive, there are spotty recycling efforts. My impression is that it's still fairly limited.
- mseebach2 14y ago
  I suspect any recycling efforts will be eclipsed by the move to screw tops.
- 7rurl 14y ago
  Recycling cork seems crazy. Why not just compost it?
  - miahi 14y ago
    Cork is valuable because it's fire and rot resistant, and also quite impermeable. This makes it hard to compost.
  - ufo 14y ago
    The problem is not that there ar emassive ammounts of cork filling landfills. The problem is that there is a shortage of cork to put on the wine bottles.
jaggederest 14y ago
To be fair, as they say it grows back in a few years and harvest doesn't kill the tree, so it's not as though they're significantly 'wasting' it. I'm sure that space programs can get all the cork they desire and more.
- miahi 14y ago
  The cork supply is not elastic. It takes at least 20 years for a tree to mature so it can be harvested, so if the market demand is doubled tomorrow, it will take 20 years for the supply to reach demand. This increases the prices and makes recycling viable.
  - hubb 14y ago
    The video linked in the article claims they can harvest a tree every 9 years.
    - scott_s 14y ago
      miahi's point was about new trees reaching the point that they could enter the 9 year harvesting cycle.
    - pan69 14y ago
      Yes. But like miahi is saying: "It takes at least 20 years for a tree to mature so it can be harvested" If cork demand doubles tomorrow it means you will have to plant new trees and it will take at least 20 years before those trees are mature enough to be harvested.
    - miahi 14y ago
      I was saying that if you want to start a cork supply business (grow cork trees because you see an increased demand), you'll have to wait for at least 25 years to make any cork at all, and probably 35 years to make any revenue. A tree reaches maturity after ~25 years after planting, and the first harvest is usually low quality, so it doesn't bring money. After the first harvest it can be harvested every 9-10 years, and you can do so for hundred of years (a healthy cork oak can live for 5-600 years). Cork does grow on trees, but slowly :).
  - raverbashing 14y ago
    Or wine bottlers can switch to synthetic cork (a synthetic bottle stopper) leaving natural cork to where it's needed most.
jordanb 14y ago
> can be used as the middle sandwich layer with carbon fiber. I've learned a lot about FRP construction and I've never heard of cork used as a core matarial. Are you sure you're not thinking of Balsa? Balsa is a hardwood despite being so light, so it has capillaries in it. The wood is cut into blocks and then the end-grain is pressed into the wetted-out FRP mat. The resin in the mat is drawn into the balsa through capillary action forming a very secure bond. Manufactured foam core material doesn't have capillaries and therefore has trouble forming a bond with the resin. If you're using foam instead of balsa core, the manufacturer will specify a bonding agent that you need to use between the mat and the core. If cork were to be used as a core, I'd think it'd have the same problem bonding with the resin as foam has, and you'd have to use a special bonding agent formulated for the cork. EDIT: Heh, after posting I decided to google around for cork FRP core. It turns out there is a company selling a core material manufactured from cork: http://www.mcmc-uk.com/products-corecork.html http://www.mcmc-uk.com/products-corecork.html; most of the users of it I can find are surfboard builders though. Here's a not-very-long thread about it on boatdesign.net: http://www.boatdesign.net/forums/materials/corecork-material-32251.html http://www.boatdesign.net/forums/materials/corecork-material...

aeturnum 14y ago

Because cork is getting more expensive, there are spotty recycling efforts. My impression is that it's still fairly limited.

mseebach2 14y ago
I suspect any recycling efforts will be eclipsed by the move to screw tops.
7rurl 14y ago
Recycling cork seems crazy. Why not just compost it?
- miahi 14y ago
  Cork is valuable because it's fire and rot resistant, and also quite impermeable. This makes it hard to compost.
- ufo 14y ago
  The problem is not that there ar emassive ammounts of cork filling landfills. The problem is that there is a shortage of cork to put on the wine bottles.

jaggederest 14y ago

To be fair, as they say it grows back in a few years and harvest doesn't kill the tree, so it's not as though they're significantly 'wasting' it. I'm sure that space programs can get all the cork they desire and more.

miahi 14y ago
The cork supply is not elastic. It takes at least 20 years for a tree to mature so it can be harvested, so if the market demand is doubled tomorrow, it will take 20 years for the supply to reach demand. This increases the prices and makes recycling viable.
- hubb 14y ago
  The video linked in the article claims they can harvest a tree every 9 years.
  - scott_s 14y ago
    miahi's point was about new trees reaching the point that they could enter the 9 year harvesting cycle.
  - pan69 14y ago
    Yes. But like miahi is saying: "It takes at least 20 years for a tree to mature so it can be harvested" If cork demand doubles tomorrow it means you will have to plant new trees and it will take at least 20 years before those trees are mature enough to be harvested.
  - miahi 14y ago
    I was saying that if you want to start a cork supply business (grow cork trees because you see an increased demand), you'll have to wait for at least 25 years to make any cork at all, and probably 35 years to make any revenue. A tree reaches maturity after ~25 years after planting, and the first harvest is usually low quality, so it doesn't bring money. After the first harvest it can be harvested every 9-10 years, and you can do so for hundred of years (a healthy cork oak can live for 5-600 years). Cork does grow on trees, but slowly :).
- raverbashing 14y ago
  Or wine bottlers can switch to synthetic cork (a synthetic bottle stopper) leaving natural cork to where it's needed most.

jordanb 14y ago

> can be used as the middle sandwich layer with carbon fiber. I've learned a lot about FRP construction and I've never heard of cork used as a core matarial. Are you sure you're not thinking of Balsa? Balsa is a hardwood despite being so light, so it has capillaries in it. The wood is cut into blocks and then the end-grain is pressed into the wetted-out FRP mat. The resin in the mat is drawn into the balsa through capillary action forming a very secure bond. Manufactured foam core material doesn't have capillaries and therefore has trouble forming a bond with the resin. If you're using foam instead of balsa core, the manufacturer will specify a bonding agent that you need to use between the mat and the core. If cork were to be used as a core, I'd think it'd have the same problem bonding with the resin as foam has, and you'd have to use a special bonding agent formulated for the cork. EDIT: Heh, after posting I decided to google around for cork FRP core. It turns out there is a company selling a core material manufactured from cork: http://www.mcmc-uk.com/products-corecork.html http://www.mcmc-uk.com/products-corecork.html; most of the users of it I can find are surfboard builders though. Here's a not-very-long thread about it on boatdesign.net: http://www.boatdesign.net/forums/materials/corecork-material-32251.html http://www.boatdesign.net/forums/materials/corecork-material...