What Is Cork And How Sustainable Is It?

2024-04-18 | By Kitronik Maker

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Courtesy of Kitronik

Guide by Kitronik Maker

Cork is such a versatile and environmentally friendly product that is a must for any ‎maker environment/classroom. If you have a laser cutter, you are good to go. It's ‎burn resistant, so once you have it on the laser cutter it can be cut and then ‎decorated with no chance of flames. More on that later! If you don't have a laser ‎cutter, then a good pair of scissors or a craft knife is all that you need.‎

We think so highly of this material that we want to make sure everyone knows ‎about it. We're going to deliver everything we know about cork and hopefully, it will ‎find a place in your future projects. If you are a teacher, this is probably one of the ‎best examples of sustainability available. If you cover Cork and Bamboo, you've ‎covered the best positive examples there are.‎

• You can download this guide as a PDF here.‎‎ ‎

What is Cork:‎

Cork is the bark from Cork Oak trees, and it is harvested from a living tree. Not ‎only does the tree not die, but it will also regrow its bark for future harvesting. A ‎lesser-known fact is that the quality of the bark also improves in quality with ‎subsequent harvests. The third harvest will yield a much higher quality bark than ‎the first. The vast majority of cork oaks come from Portugal and Spain and the ‎trees are harvested in peak growing season, which is between May and August.‎

The primary use of cork is to produce wine corks, which are made from the best ‎quality cork available. Once the material for wine corks has been segregated, the ‎remaining is then made ready for all of the other potential uses.‎

Cork undergoes very little processing, the majority of the time the cork is in ‎storage, laid flat on pallets. The sheets are then immersed in clean, filtered boiling ‎water to remove any impurities and are then stacked flat to dry and cure. The ‎result of this is that the cork is softer, flatter, and easier to work. The cork that is ‎not being used for premium quality wine corks is then ground up and formed into ‎shape with high temperature steam.‎‎ ‎

Sustainably Harvesting Cork:‎

On average, trees can be harvested once the tree is about 25 years old. The trees ‎are then harvested every 9 years. It usually takes three harvests before a tree ‎begins to yield premium-grade cork. The trees are approximately 43 years old at ‎this point. Cork trees usually live for around 200 years and can be harvested more ‎than 15 times.‎

The main downside of removing the bark from the oaks is that it leaves them more ‎vulnerable to forest fires. The bark is resistant to fire and is such a good thermal ‎insulator that unharvested trees can often survive when all else around them ‎perishes. Aside from that, the trees remain perfectly healthy after harvesting and ‎the next bark growth will be of better quality than the last.‎

Cork is 100% recyclable. Not only is cork the best material for a 'cork' for bottles, ‎but it also has by far the smallest carbon footprint when compared to any other ‎type of bottle stopper material.‎‎ ‎

Cork Properties:‎

Being environmentally friendly is a big plus in corks favour, but its usefulness ‎comes directly from its properties. On paper, cork looks like a super material. Let's ‎explore them.‎

• Acoustic insulation - Cork has very low vibration conductance, making it ‎good for decoupling and sonic insulation.
• Thermal Insulation - The trapped air in the cork is in isolated bubbles ‎which makes it a good thermal insulator.‎
• Fire/Temperature resistant - It doesn't burn readily when it does burn it ‎does so without a flame and doesn't emit any harmful gasses. The lack of ‎flame lowers the chances of it becoming an ignition source for other ‎nearby materials.‎
• Excellent mechanical properties - It has excellent elasticity and ‎compressibility properties, which means it can be put under considerable ‎stress without permanent alteration.‎
• Light/Buoyant - Because of its high air content, cork weighs very little and ‎floats.
• Hypoallergenic - Cork does not absorb air particles from its surroundings, ‎such as dust and pollen. This makes it a good material of choice for those ‎with certain allergies.‎
• Impermeable to liquids and gasses - The properties of the cell walls that ‎make Cork resistant to both gasses and liquids also means that it ages ‎well and without visible deterioration.
• Resilient - Cork has excellent resistance to impact and abrasion.‎

Add to the list that cork is soft and pleasing to the touch, making it an ideal finish ‎on items that will be handled. This brings us neatly onto potential uses.‎‎..

Potential uses for Cork:‎

Cork has so many things going for it that it is a must for any making environment. ‎Cork is a waterproof material that is also surprisingly durable. It has good elastic ‎and compression properties and excellent thermal, acoustic and anti-vibration ‎resistance. These all combine to make it suitable for a wide range of uses.

‎As well as the obvious cork boards, some other possible uses include coasters, ‎mouse mats, heat/sound insulation, to decouple a project from a work surface, as a ‎covering to improve the tactile nature of a product, gaskets, a protective layer or ‎bumper, business card, and the list goes on and on. Cork can even be used as an ‎alternative to leather. ‎‎ ‎

Cork Options Available from Kitronik:‎

At the time of writing, Kitronik stocks cork in sheet form. We carry them in 1mm ‎and 3mm, 600mm by 400mm sheets, plus one in a larger sheet size. We also offer ‎sheets with adhesive backings, so no glue required! They are

• ‎3mm Laser Cork, 915mm x 610mm Sheet.‎
• ‎1mm Laser Cork, 600mm x 400mm sheet.‎
• ‎3mm Laser Cork, 600mm x 400mm sheet.
• ‎1mm Laser Cork with Adhesive Backing, 600mm x 400mm sheet.
•  ‎3mm Laser Cork with Adhesive Backing, 600mm x 400mm sheet.‎‎

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