Waste not, want not.

Posted by on Oct 13, 2013 in Blog | No Comments

Wood working inevitably involves some waste. At the start of a project I calculate the timber required for the job then add an allowance for wastage.   Often, depending on species, this allowance will be over 50%.  Surely you can be less wasteful than that I hear you cry!  However when you look at the waste factors you will see how I come up with this figure:

  • Wany edge and sap wood.  Often the wood comes from the yard in boards sawn directly from the tree.  They will still have the bark attached, and sap wood in a layer below the bark which has to be cut away.
  • Even boards square-edged at the timber yard will have some sap wood.  The amount varies according to the species.  In beech, for instance, the sapwood is indistinguishable from the heart.  In walnut the sapwood is a light creamy colour while the heart is a rich brown, so the sapwood has to be avoided.
  • Depending on the original quality of the boards, there will usually be some defects such as dead knots and cracks caused by the drying process.  If a rustic effect is required, knots and cracks are not such an issue, but generally with fine furniture these will be cut away.
  • Some wood will disappear when machining. We might buy a one inch thick sawn board, which will convert into a planed board about ¾” thick – 25% is lost just in the  planing.  The amount lost may be even greater if the boards are warped.
  • Finally there are offcuts. The bought board may be eight foot long but we need two pieces 42” long, which leaves an offcut one foot long, which is not much use.

Some woods are notoriously wasteful.  Yew, for instance, with its white sapwood cracks and ingrown bark often has a wastage of 75%.  English walnut also has a high wastage.

At the start of each project I usually look at the pile of timber and think I have over-ordered, but sometimes I have to sneek back half way through making, to pick up some more!

What can be done to mitigate some of this wastage?  To start with, I have a very efficient wood-burning stove at home which is fed all winter with workshop offcuts.  As autumn approaches, the stack of offcuts in sacks in my store room mounts up, then dwindles to nothing in the spring. My stove is a Danish Hwam which I would recommend to anyone http://www.hwam.com/.

Lately I have also been looking to make small items from my offcuts – a student on work experience made some chopping boards and toast rack which brought in a few sales during the recent Ilkley Art Trail.  Even though the Art Trail is over, I welcome visitors to the workshop unless I’m teaching, so why not call in to see what I do – you could help with my wastage problems by buying a toast rack!

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Thankyou, Chris.

 

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