Raw cork stool by Steven Li Wei Hsiao

Raw Cork Stool Steven Li Wei Hsiao

CONTENTS

Introduction

Raw cork stool

Why cork bark?

Inspiration

Good things about natural cork bark

Development

Details of plank stool

Reflection

Appendix

Reference

Bibliography

Acknowledgement

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Introduction Cork is the bark of the cork oak, the only tree capable of naturally regenerating its bark after removal. It is a 100% natural, sustainable, carbon negative and recyclable material. 1 The inspiration of making a cork stool originated from when I saw a debarker separating cork bark from its oak; as the bark peels, the natural curve of the cork bark mimics a comfortable stool. Cork has always been associated with champagne and fine wine, yet it has a more humble origin which began in Portugal. It has been used as seals for centuries, where it can be easily squeezed into bottle; its physical property allows it to spring back into its original form, immediately creating a prefect impermeable barrier and stopper for fluid. Aside from a natural bottle stopper, cork as a material has mostly been explored and utilised in granulated form. From technical stopper, flooring, insulation to composite, however, many of us are unfamiliar with the true form of cork. Cork, in its natural from is intrinsically soft and lightweight, however it lacks in tensile strength. 2 In this project I explore the different methods to provide cork with this extra property. The combination of the natural features of cork with tensile strength will produce the effect of a soft and natural appearance. The aim of this design is to create a stool which displays the natural cork bark quality, with a minimalistic structure that allows cork to function as a stool.

Back to cork bark In order to promote and develop cork as a raw material of excellence. Portuguese cork industry are inviting designers to design corkbased products and derivatives. For example on the left, Par: salt and peper by Nendo, Bote by Big-game, Pinha by Raw Edges and Cru by Sebastian Bergne. However, most of the designs are made in granulated cork rather than its original cork bark form. This lead to many of us are unfarmiliar with the original quality of cork bark. This is why I want to design using natural cork bark rather than granulated cork.

Natural stool Cork is the bark that protect the cork oak. It is naturally suitable for outdoor use. It is soft, lightweight, near-impermeability to liquid and high abrasion resistant make it ideal for a stool.

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What is good about natural cork? Disadvantage

Challenge • Preserve cork bark as a piece

• Near -impermeability to liquid and gases

• Cannot dye through - its nearimpermeability only makes it dye on the surface not inside.

• Highly compressible

• Trap water and gases

• Better bending ability

• Excellent thermal insulator

• Irregular shape and uneven surface

• Good Acoustic insulator

• Inconsistent bark quality from one to the other.

Advantage

• Lightweight

• Fire retardant - slow burning • high abrasion resistant • Low density - float on water • Low electricty conductivity • Recyclable

• Add tensile strength

• No tensile strength • Fragile in thin slice • Hard to preserve surfaces as a whole • Snap easily when bending

• Reuseable

Conclusion

The application of natural cork is rather limited due to the lack in tensil strength

CUT, SLICE AND COMPRESSION 1

3 1. When slicing cork layer, the top and bottom of the cork is difficult to preserve as a complete piece. Cork has very uneven surface. 2. When bending cork, it snaps easily. 3. Cork have great compression strength. When compressed, higher density gives cork very hard surface.

4. Experiment on compress a cork plank by a simple jig. 5. Cork plank cannot take compression pressure, goes side way and break. 6. Laminate with different materials, by doing so, it will be easier to compress, since cork is in smaller strips.

From left to right: weld mesh, Aluminium mesh and Aluminium tape. Aluminium tape does little for cork. 7. Compression testing on cork laminate with weld mesh and Aluminium mesh. 8. Aluminium mesh breaks and goes side way, 9. Welded mesh still holds, but the bottom half of the cork starts to crack. Crack stops at mesh. This reminded me of reinforce concrete structure. It might be a good soultion to weak tensile strength.

1. During slicing cork planks, theof trying to preserve the top and bottom of the cork / as a piece led me to slice other direction.

CUT AND LAMINATE

2. Laminated cork with welded mesh and Aluminium mesh. It

was sliced from other direction, therefore the bark is on the side way . The strength of this laminate cork, can hold 10-15kg weight which normal cork strip cannot achieve.

3. This stool was made based on the previous experiment. By slicing from the other direction, cork bark is on the side, but I wanted to show the cork bark from the front side. I also tried to use the whole plank without wasting any cork.

LAMINATION WITH OTHER MATERIALS 5

1. Various meshes, varaform, woven tapes and gaffer tapes.

3. Four different combinations of cork laminated strips.

2. A mould was made for easy bending and easy to laminate with other material. Steaming cork makes it softer and easier to be bent.

4. Weight test - 60kg person. 5. Weight test - myself (55kg) standing on single strip.

LAMINATION WITH PRE-STRESSED STEEL WIRE 1

From previous tests, 6-7 slices of laminated cork is strong enough for sitting, but what is the mininum thickness required? 1. Work in progress - two slice cork laminate with single varaform layer.

2. Weight test - two slice cork with varaform break, same as three layers. Maybe varaform with welded mesh was not the best combination. 3. Pre-stress 1.5 mm steel wire and laminate cork onto it. When release stress, steel wire sprung back and gave a small amount of compression to the cork which provides a much simple solution and the strength thatâ&#x20AC;&#x2122;s required.

1. Modify a standard chair to be used for investigate ways of fixing cork strips onto frame.

STOOL PROCESS 6

2. During the making of this chair to suits my need, I started to design my stool that needs to be simple and only has simple

structure that allows me work around the stool. For example, this chair cannot allow me to test spot welding, because its angled frame. 3. Spot welding strength testing, either weak weld or weak wire.

4. MIG weld is inconsistent melting the wires. 5. Knotting - after knotted, wires doesnâ&#x20AC;&#x2122;t provide spring back ability that a stool should have. 6. Clean ferrelus and crimp solution.

1. A foamboard stool structure that consist the required strength. 2. Label cork slice positions. 3. Cutting cork slice 4. Laminate cork onto wire, but keep small amount of tension.

What can be done to improve further and carry on development? As every plank is unique and grow in different ways. After cork barks have been harvested, there is a six months period that cork barks are left outside to stabilize. Cork barks at this moment can be clamp to be flattened, or this can potentially be done right after first boiling process. By doing so, it is easiler to be processed without waste of any barks. From the previous development, when creating a radius corner of the stool, cork strips cannot be easily aligned, there are alway gaps or difficult to put cork strip aside each other perfectly. This is because the cork is not flattened. When cutting with angled bendsaw, it will end up cutting in various angles. On the other hand, only cutting half way of the cork bark creates a easy break point. By flatten or even compress cork barks into regulated shape. This can potentially make cork bark be more consistent in quality and to be processed. Instead of laminating other materials into cork strips, it is possible to try more composite approach - by vaccum air inside the cork and release the vaccum under resin, liquid rubber. This will give cork a sponge quality and infiltrate the cork cell structure with rubber or resin, this can potentially reinforce cork from the inside.

APPENDIX Nose to Tail eating by Fergus Henderson

The author states that “ ‘Nose to tail eating’ means it would be disingenuous to the animal not to make the most of the whole beast” “A reminder - and a respectful one at that - of what is good about food - about the essential, nearly forgotten elements of a great meal, a homage, an honouring of the foodstuffs we eat, a refutation of nothing more than waste and disregard.” Throughout this project, this idea of preserving every part of the cork, not to waste and reuse any off-cut is strongly influenced me.

Exploring cork Thermal insulator

Explore thermal insulation ability of cork, how well it can wrap around the cup. The idea behind this was the cork sheet can be kept and reuse and provide a much better thermal insulation to conventional recycle paper wrap.

Weaving

Explore possible weaving cork to strengthen its bending ability and stronger structure. The difficulties was cork bark is very inconsistent so very small amount of good slice was gain from large amount of cork.

Water impermeability

Build a cork block in order to lathe into a cup. The natural cork bark have natural hole and gap within it, so it is difficult to seal all the leakage. But the cup itself was very nice to hold on to. The off cut from making of this cut was considered and reused.

Laminate

The off cut are used to be glue and laminated into one piece. The intention was to use lamination technique from plywood. The cork lamination slowly fall back to flat because its cork cell structure that provide cork from spring back to its original form.

Work with glass

Cork has always been associated with champagne and fine wine. By utilizing off cut strip from natural cork production. Amendment was made to use for holding wine bottles.

By using empty bottle to be the leg of the cork bark. Soon was developed into a wine bottle holder with the ability to be a chair. Glass bottle was taking over the cork. It was driving away from my orginial intention.

Reference

Bibliography

1. 100% natural, sustainable, carbon negative and recyclable material http://www.realcork.org/artigo/9.htm

1. Corticeira Amorim S.G.P.S., S.A, Amorim Group 2. APCOR - portuguese cork association 3. The cork industry federation - http://www.cork-products.co.uk/index-2. html

2. Properties and uses - http://en.wikipedia.org/wiki/Cork_%28material%29 3. Nomu by Lee West for Eno 4. Pinha by Raw Edges 5. Wine & Bar by Aurélien Barbry for Normann Copenhagen 6. Appo by Carlo Trevisani 7. ‘Tupa’ by Marina68 8. Bote by Big-game 9. Cru by Sebastian Bergne 10. Cortiça chaise lounge by Daniel Michalik 11. Cork lamps by Benjamin Hubert 12. Par: salt and pepper by Nendo 13. Image copyright by APCOR 14. Various source on cork properties - http://en.wikipedia.org/wiki/ Cork_%28material%29, http://www.realcork.org/artigo/14.html, http:// repositorium.sdum.uminho.pt/bitstream/1822/4005/1/0105.pdf, http://www. materialproject.org/wiki/Cork 15. Fergus Henderson, 2004, Nose to Tail Eating, New edition edition, England, Bloomsbury Publishing PLC

4. Granorte - http://www.granorte.pt/ 5. Observatório do Sobreiro e da Cortiça 6. Portugal pavillion expo 2000 7. Portugal pavillion expo 2010 8. Neoprene Veuve Clicquot Non Vintage Champagne - http://www. thechampagnecompany.com/champagne/veuve-clicquot-champagne/ veuve-clicquot-non-vintage-champagne-yellow-label-75cl-ice-jacket/ prod_17.html 9. Screwfix for turnbuckle and other items- http://www.screwfix.com 10. 3M for tape testng - www.3mselect.co.uk/ 11. Flints for ferrelus, wires and crimp tool- www.flints.co.uk/ 12. Corkatable: cork and steel for SUS Design 2008 by Marco Sousansantos 13. Torno by Inga Sempe 14. Parte bowl by Nendo 15. Suave by Simon Mount/Miguel Cunha 16. Tatami table by Aichi Japan 17. Natura by Héctor Serrano for La Mediterranea 18. Plug by Tomas Kral 19. Flashlight by Joseph Guerra

Acknowledgements It is a great pleasure to thank everyone who helped me on my cork journey and project. This project would not have been possible without their help and support. Colin Holden Simon Hasan Martin Harding Claudia Pimenta Conceicap Santos Silva Miguel de Sousa Jose Augusto Lopes Infante Ramiro Tavares Eduardo Sousa My fellow classmates - Trine, Verena, Chloe, Hermann, Hend, Yi-Ying and Yu-Pu. My parent and also Wendy, Eric and Ting.