Wenge

"One man's junk is another man's treasure"

......and spalted wood embodies that truism.  Wood turners and wood workers alike hold it in high esteem for its natural beauty.  Because spalted wood is consistently inconsistent in appearance, it is in high demand.  Each piece is unique.  

Spalting occurs in many species but is most commonly seen in our local woods; alder, birch and maple.  The spalting process occurs at different rates for different woods and depends on climate and environmental factors.  The characteristic blue-black zone lines of spalted wood form when incompatible colonies of fungi come into contact with each other and lay down barriers to separate their territories.  This phenomenon represents the early stages of decay. 

Producing spalted wood for the workshop is, although a hit and miss process, completely attainable.  The key to stimulating wood to spalt is providing the moist, warm environment that the fungi thrive in.  The most taxing challenge is calculating when to halt the process to arrest the spalting. 

The simplest method to promote spalted wood, but the hardest way to control it, is to put logs into a shady wood, cover with leaves or bury in sawdust and keep moist.  The sawdust can add to the colour, and while mushrooms and roots grow, they leave trails and irregularities.  For better control, and in dealing with smaller sized pieces, place the wood in plastic bags and keep moist.  Here are some options: 

1. Seal the end grain of your selected fresh-cut piece, leave the bark on and store in a dark, moist environment.  Do not use dry wood.
2. Create a 'spalting paste".  Spread the paste covering the surface of a rough-turned piece.  Place in a plastic bag and leave in a warm place for several weeks.

Spalting Paste #1

1 ½ tablespoons of ammonia (non-sudsing type)
1 cup of nitrogen-rich fertilizer (mixed double strength)
Oak leaves

***And like any good sourdough recipe, it doesn't hurt to have shavings from spalted material of the same species to act as a "starter". 

Spalting Paste #2

1 litre or quart water
1 cup nitrogen-rich fertilizer (granules)
1 can beer
1 litre/quart manure (rich with ammonia odour)
Oak leaves 

Spalting Paste #3

Any mix of nitrogen, organics, ammonia, sugar, malt extracts, tannins and leaf molds - everything necessary to stimulate all many of weird and wonderful growth.

Check after 2 months.  You are looking for a black slimy mess with external growth.  Mushrooms are good.  However, there are no guarantees.  Mother Nature can be capricious at best.

The dust created from sanding and sawing spalted wood has a toxic nature with a reputation for causing respiratory problems.  More specifically, the mold/fungi can trigger severe reactions like asthma.  A small percentage of the population can be expected to develop allergic sensitivity to one or more compounds found in wood.  If you handle a lot of potentially toxic species, and work with them long enough, you increase your chances of a reaction.  So, the best defense is to wear a dust mask or full face biologic filtering respirator and use a good dust extraction system; it doesn't hurt to have a fan blowing the dust away from your work area also.