Here’s a fairly late update from Jan’s wood.  Since my last post, March in Cumbria has been a whirlwind of all sorts of weather.  There was, of course the mad snow storm which blocked our main road, and then while most of England was bogged down by heavy, relentless rain, we had 2 weeks of gorgeous bluebird days, extremely cold and windy, but wonderfully sunny.  I managed to warm up the camera long enough to give a little idea of where I’ve been working.As soon as I got back to the woods from a good trip to London, I needed to get back to the wood and play, learning from books written by those who specialise in this organic material.  By learning to use and manipulate the greenwood’s properties like so many talented craftsmen before, I hoped to find way of developing a system that will allow me to create furniture.  I’m a sucker for symmetry and I like to design the outcome, it’s the control freak within, however, greenwood does not conventionally work this way.  Perhaps there could be a compromise?  Cleaving is a fascinating process of knocking a blade down the centre of the wood.  It will naturally split along the grain.  If the split travels in the wrong direction the tool, called a froe, can be levered one way or the other to encourage the split along a clean line down the length of wood.  Hence, to and froe!  This has given me some beautifully symmetric material, albeit still organic and irregular.

Another brilliant use of greenwoods properties that I have always wanted to explore is shrink joints.  When felled, timber has the moisture content of 30% upward to as high as 60%.  As it dries the cells shrink.  Greenwood workers turn dowelled furniture components, pre-dry them and use them in green mortise holes.  These mortise holes dry and shrink around the pre-dried tenons – glueless joints.  I love this method, using only the natural behaviour of the material to construct solid furniture.

So I mocked up a silly chair sketch.  Crack Willow was really not the most sensible wood to use, I’ll admit.  I have to add, during this point I was aware that this traditional process involves a long time.  Greenwood workers are calm. patient souls, allowing their material to slowly dry or season.  Unfortunately time is not my luxury, and in the scheme of trying to find an industrial process for greenwood, these exercises were not proving the right direction.While I was in London, and with access to the metal workshop at Uni I thought I’d have some fun making my own tool.  I love the concept of cleaving, but I wondered if that moment of splitting could be capitalised to form extruded shapes.  Would I be closer to making my uniform components from supple greenwood?

Nope.  The middle ‘punch’ of my tool did a good job of dowelling my log, until it got wedged in the grain.  As for the splitting froe wings, the split ran away in front  of the tool as soon as it got it’s teeth into the end grain, so all control was lost.  As this tool was a complex and lengthy process to make, I abandoned this idea.  However it certain helped me understand the nature of the grain and inner structure of my wood.  It did a great job of creating perfect tenons for my shaving horse legs!

While playing in the wood, making a shaving horse and fiddling with these ideas, I have become increasingly appreciative of my chainsaw.  It makes light work of rough shaping and cutting to length, but it creates a great amount of mess.  There are shavings everywhere!  More about chainsawing next time…

I had some willow shavings soaking happily in my potash alkali for a few weeks.  Time had come to do something with it.  Going back to the advice from Bio-composite Centre I re-boiled the solution with a bit of whisk/friction.  After a 2 hour cook the shavings were scooped into my make-do metal mould.  It was G-clamped up as tightly as possible and left to dry.

The shavings were checked after 3 days.  Were the wood had dried and had been compressed the most, there was definetely bonding.  Exciting stuff!

The sample was placed back in the mould and the whole thing was placed over a stove to apply some heat.  It was left there to sizzle away until I was sure all the water had evaporated away.

Once everything had cooled, the clamps were removed.  The shavings had successfully bonded together.  The surface that was on the metal mould side and over the heat had a very smooth and shiney finish.  I had created my own glueless particle board, a course masonite board.

I can only presume the cooked cellulose and lignin had acted as a bonding agent when heat and pressure is applied.  Unforuntately the the material isn’t water resistant, but there is still some potential with this aplication within my woodland.

What is refinement?  Investigate the refinement of a base material towards the creation of a refined product.

My starting material had to be wood.  However, coppiced wood has been a draw to me for awhile due to its totally sustainable and low-impact cycle.

Coppicing is a tradition of woodland management; working to a cycle of growth of trees which have been sensitively selected and felled for regrowth.  Trees have dormant buds lying in wait under their bark in defense to damage, like getting munched by Mammoths or stamped on by any other significant mammal.  As the network of roots remain, replacement growth happens considerably faster than for a new tree to grow from seed. For centuries humans have manipulated this natural trait to provide an abundant supply of raw material.  After every harvest, a tree stool will provide, on average, 3 times the number of new shoots.  Historically, coppiced areas are left for 5-7 years to regenerate and produce quick grown, straight poles, prime for the greenwood craft industry.

Essentially, coppice is a sustainable and truely renewable source of carbon-neutral material.  Whats-more, its potential is everywhere.  There are around half a million acres of unmanaged woodlands in the UK.  To see a new wave of industry utilising this resource for our markets and manufacturing would be a huge step forward for the conservation of our countryside.

The draw back in working with such a material is that it’s inherent beauty and purity, it’s organic-ness makes it difficult to take coppiced / green wood forward as a realistic contender for batch production.  To work with it is labour-some and time consuming, if not for stunning results.  Now, how can I make afford products with this environmentally affordable material?

Of all the green wood craft, I am most intrigued by Swill Baskets.  The principle is taking green Oak, granted as straight as possible, and boiling it for at least 24 hours allowing it to be split to fine strips.  Essentially the wood is being made into a generic form of itself, to be flexed and weaved into a basket.  As it dries the wood hardens and the basket becomes incredibly strong.

It is the reaction of the wood to the boiling that has intrigued me.  What happens to the make-up of the wood to make it go pliable when wet, and retain shape and rigidity when it dries?

To understand wood a little better, on a microscopic scale I got in touch with a research scientist from Innovia Films.  They produce cellophane by the tonne.  Cellophane is pure cellulose extracted from wood pulp.  The process of extraction is fairly similar to paper making.  Huge quantities of wood pulp are re-boiled in a water and Sodium Hydroxide solution; a soup that speeds up the separation of cellulose from the 2 other essential ingredients in wood (The Kraft process).

Now here’s the bio-chemistry bit.  Wood is made up of cellulose, hemi-cellulose and lignin.

Cellulose is the structure of the wood.  The molecular fibres which act together to create rigidity.

Hemi-cellulose is the ‘string’ that holds the cellulose fibres together.

This knot of cellulose is set in lignin.  The ‘resin’ which glues the structural molecules together.

When the cellophane and paper makers, as well as swill basket makers, boil their wood they are diluting the lignin.  In the example of boiling and steaming wood in the wood craft industry, the dilution of the lignin allows the wood to be bent and formed into new directions.  As the water evaporates and the lignin condenses, the wood stiffens and retains its new shape.

From this finding I have been developing an interest in Lignin and what it’s properties could be used for.  Although a waste product from these different techniques, it has a great calorific value, it has more carbon content than wood itself.  The Kraft process burns the recovered lignin to recycle its energy back into the system.

Understanding these two comparably different scales of wood manipulation, I started to wonder if the use of Sodium Hydroxide (Caustic soda) in the industrialisation of cellophane was completely necessary.  Reading into the science of woods molecular bonds I believe a high pressure and high temperature hydrolysis method would be enough.

First step: Try to cook and separate wood at home with a Pressure Cooker.

The smaller the carrots the quicker the cooking, right!?  I reused the brown water from the previous cook.  I figured I’d intensify the concerntation.

Although the sight of a pressure cooker steaming away on the stove was a regular occurance during my childhood, I have no idea how to use one, especially when cooking wood for 6 hours.  The water levels were calculated wrong and that was the end of this test.

These tests were an interesting starting point.  I’ve been left with some interesting brown liquour.  Somewhere, floating in this milk bottle is weaker bonded lignin.  The wood has barely changed, so the cooking process definitely needs taken up a knotch or two.

To the laboratory…