D for Damaged, Diseased and Dirty Wood
This month we take a look at something we nearly all do - that is use pieces of damaged, diseased or dirty wood to turn items. This may be understandable when faults in a piece of wood enhance a finished item, whether by colour, grain, patterning or inclusion of the fault as a feature. What is not acceptable is that in attempting to turn a damaged blank (this probably means a cracked blank) the wood disintegrates into several pieces which have sufficient energy to cause significant damage to the lathe, adjacent machinery, the workshop, the woodturner or anyone else in the vicinity.
Neither is it acceptable to give our respiratory system a liberal dose of dust from spalted, diseased or weathered timber or from the dirt and dust which has been picked up or settled on the piece whilst it has grown in the wood, lain on the ground after felling, been processed in the woodyard and then been stored in our musty timber store for years.
Spalting results from timber lying in the wet until it begins to rot when it is attacked by various forms of fungi which produce the characteristic marking. Do we clean up a piece of wood with a stiff brush before putting it on the lathe? In most cases we assume that the first few cuts will soon clean up the wood even though it probably contains enough grit to quickly take the edge off the gouge.
We therefore have to assess the risks of using less than perfect timber to produce our turned items. Any piece of wood, if rotated fast enough, will eventually fail - therefore lathe speed is an important consideration. We need to be aware that taking more gentle cuts with a smaller gouge may be required and extra care taken to avoid dig-ins.
The importance of facial protection from debris, whether pieces of wood or bark and respiratory protection from dirt, dust, fungi spores and bacteria cannot be overstated. I attended a presentation where a piece of wood with rotted sapwood but sound heartwood was being worked on. As turning commenced the lathe, the presenter and then the first three rows of the audience quickly disappeared in a cloud of rotten wood.
When we first start to turn a piece of wood does it resemble a Saharan sandstorm or are we pelted with pieces of loose bark and debris?
LEARNING POINT - Use appropriate facial protection to
protect from impact and respiratory risks.