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Tauranga Woodcrafters Guild Inc.

 

 

Key Information on NZ Timbers

 

Woodworkers in NZ can use Native NZ Timbers and wood from various introduced species. NZ Native timbers are a wonderful resource for woodworking crafts, especially woodturning and wood carving. Information on NZ Native timbers is readily available on various Internet sites including the National Association of Woodworkers (NAW) NZ and the NZ Department of Conservation web sites.

NAW also provides information on health risks and toxicity associated with introduced tree species. NAW make the point that "as a general rule dust from every wood is toxic if you inhale enough of it."

Given the depth of information which is available elseswhere we have elected to simply provide some key Woodworking and Health notes about NZ timbers which Tauranga Woodcrafter Guild members may find themselves using.

Timber

Woodworking Notes

Health Notes & Density @ 12% moisture

Kahikatea

Also known as White Pine.

Timber is white with a pale yellow heart and is very straight close grained, but tends to be soft and dents easily.

No odour and does not impart any taste and for this reason was used for butter and cheese boxes, Suited to making household utensils, bowls and ladles.

Not a popular turning wood but heart wood is preferred as it has a bit more character. The sapwood is very susceptible to attack by the common borer.

A friction polish produces the best finish - it can look rather muddy with an oiled finish.

There are currently no known health risks associated with working this timber.

Density - 460 kg/m3

Kowhai

Kowhai timber has a dark brown patterned heart wood with lighter brown to yellow sap wood wth a nice grain. The timber is very hard, dense and durable and turns and finishes well.

It is a popular turning wood and is especially suitable for fine work.

An oil finish deepens the colour and gives a lustrous finish.

There are currently no known health risks associated with working this timber.

Density is around 870 kg/m3.

Maire

There are four species of Maire. The most common ones in NZ are White Maire and Black Maire. White Maire wood is yellow to light brown in colour and black Maire is darker brown with very dark to black stripes through it.

Timber today is rare. Has a characteristic smell when turning and finishes well with a natural high polish.

Timbers of both species are extremely hard and dense. It needs to be worked with very sharp tools. It produces an excellent finish with sanding. The natural waxiness of the timber results in a highly poished finish.

It is especially suited to furniture and cabinet making. It has been popular for woodwind musical instruments. Very good wood for woodturning and carving ornamental and fine details. Paper thin translucent turned work can be achieved. A known challenge is a tendency to produce hairline cracks.

There are currently no known health risks associated with working this timber. The dust is not considered as being toxic.

Density is around 950 - 1,000 kg/m3.

Matai

Timber can be variable in colour but is generally a lovely golden brown when polished.

It was used extensively for floor boards in houses where it stood the test of time and stiletto heels!

Matai dries well with minimal disortion. Very suitable for furniture making, turninglarge bowls, lidded boxes and hollow forms. It has straight grain and is harder and heavier than many other NZ Natives, but it is easy to work on the lathe. Pleasant smell when turning.

Produces silky lustrous finish(but heat cracks need to be avoided). Easy to maintain and refurbish with a good polish. Resists damage from knocks.

There are currently no known health risks associated with working this timber. The dust is non toxic.

Density is around 610 kg/m3.

Miro

Similar in colour and grain to Rimu.Heartwood is a lighter biscuit colour with dark reddish to black streaks, with a light beige colour sapwood. The heartwood cross-section section is irregular, allowing beautifully figured sawn timber.

Miro is slightly stronger than Rimu hard and elastic. It is not suiteable for exterior use, but excellent as an indoor finishing timber with good machining properties.

It turns and finishes well. It coats easily, and the timber lends itself to being steam bent. The dry heartwood is, however, prone to splitting, and should be pre-bored for nailing.

There are currently no known health risks associated with working this timber. The dust can be irritating but is not considered toxic like Rimu.

Density is around 650 kg/m3.

NZ Kauri

Woodworkers find Kauri good to carve and to turn.

Timber is a warm honey colour with the close straight grain giving a small fleck. A good transluscent finish can be achieved.

Resinous wood can be difficult to sand and finished items are prone to denting.

Head and stump wood both produce spectacular turned bowls and platters.

When working this timber it is possible for dust to irritate the nose.

Density is around 560 kg/m3.

NZ Swamp Kauri

Swamp Kauri is suitable for turning and carving.

The minerals absorbed while in the swamp, makes it more absrasive on tools but adds an interesting additional lustre & dimension to the colours which vary from dark brown to green.

When working this timber it is possible for dust to irritate the nose.

Density is around 560 kg/m3.

Pohutukawa

The timber is extremely hard and dense,

Early Maori used it for weapons and the keels of boats.

It was never used commercially but is a beautiful timber to turn. Mature heart wood is very dark red in colour, and younger trees produce more pinkish timber.

Spalting (decay), bark inclusions and compression stress produce attractive grain patterns but can also make this timber a challenge to turn.

It is often used for exhibition or artistic pieces.

There are currently no known health risks associated with working this timber. The dust is not considered as being toxic.

Density is around 950 kg/m3.

Puriri

It is now a treasured timber for turning because it is in very short supply.

Puriri is related to teak. The timber can vary from dark green to black and is extremely hard to work.

Ony a small quantity is now available. Old fence posts are sometimes available,

Very popular for turning. Cuts well with sharp tools. Polishes well.

There are currently no known health risks associated with working this timber.

Density is around 900 kg/m3.

Rata

There are two kinds of Rata - the Northern Rata (mainly found in the North Island) and the Southern Rata (found mainly in the South Island).

Wood is a dull reddish brown in colour, with distorted grain exceptionally hard and dense.

It shrinks considerably on drying. It is hard on machinery. It is not very stable in use, nor very durable.

It is popular with woodworkers because of the warped reddish grain. However, it can be difficult to turn when dry. Northern rata may produce hair cracks and burrs can be very hard to turn, but it holds colour well. Southern rata is less stable and better suited to small pieces which disort less.

There are currently no known health risks associated with working this timber. The wood and dust is non-toxic.

Density is around 880 kg/m3 for northern rata and 1,140 kg/m3 for southern.

Rimu

Rimu is one of the most popular of NZ native timbers. It is highly prized for furniture making.

Dry heartwood varies from yellow to dark reddish brown. The timber is straight grained and machines well.

Woodturners really appreciate the texture, colour and hues of this timber, it takes a good finish, but sanding of end grain can be difficult.

Rimu is well suited to bowls, platters and artistic shapes - rimu burrs are highly prized.

Rimu dust tends to irritate the eyes and nose.

Density is around 595 kg/m3.

Tawa

Tawa has been widely used for building, especially flooring. It has also been used for furniture and internal fittings and panelling.

The wood is a pale buff colour with a nice grain. The heart wood and knots are an attractive dark brown with some black streaks.

Commonly used for turned handles, rollers, furniture, interior finishes. The combination of dark hlines running through the whiter wood make Tawa attractive for woodturning.

There are currently no known health risks associated with working this timber.

Density is around 720 kg/m3.

Titoki

Titoki wood is light red in colour and straight grained and hard, with great strength, elasticity and toughness.It is rarely used for woodworking projects.

The timber was used by European settlers where great strength and elasticity was required but it is not durable so essential that they be kept under cover when not in use. Other uses were tool and axe handles, swingle trees, cabinet making and particularly where strength and bend-ability were important.

Titoki is known to liberate hydrocyanic acid. However no death or sickness has been recorded.

Totara

Totara was recognised by early Maori as valuable for carving and canoe building because it was easy to work and was very light and durable in water.

Timber is a beautiful dark red and very straight grained. Soft, easy to work and has a natural preservative in it so has a very long life when used for outside structures. Because of this natural preservativ, it must be primed properly before painting and sealed before applying any woodturning finishes.

Most Totara used today for turning is recycled old fence posts that are now in short supply. It is easy to turn but tricky to finish. The natural gum in the wood clogs up sandpaper. Furthermore oils in Totara react with many finishes leaving a fine "bloom" of salt like crystals in patches. This can take a week to appear. It is important to experiment using scrap wood before treating the final piece.

There are currently no known health risks associated with working this timber. Dust from sanding is not considered toxic.

 

Density is around 480 kg/m3.

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