Woods to Know: Pau Ferro - Canadian Woodworking Magazine

Woods to Know: Pau Ferro

Pau Ferro (Machaerium sp)

With the demise of many species of the esteemed rosewood family woodworkers have been looking for substitutes for these increasingly rare woods. Pau Ferro (also known as Santo's Rosewood) is a popular replacement. Several species make up the Pau Ferro group with only minor differences between them.  
Native to tropical South America, the tree is common to Brazil and Bolivia where it prefers the drier areas of the forest. It is a medium size tree typically around 60 - 65 feet tall, though exceptional specimens can reach 100 feet with diameters approaching 5 feet.

Pau Ferro is noted for its richly coloured heartwood. Black and brown stripes can wind through the heart on top of reds, oranges, yellows and even bluish tones. This striping is often emphasized when the wood is quarter cut yielding a distinctive linear appearance. The colours in the heart can appear to twist and swirl giving the wood a very unique look. The sapwood is pale-white to yellowish-white and is sharply demarcated from the heart. All of these features combine to mimic the classic appearance of many of the true rosewoods. 
Pau Ferro is considered to be straight grained, although it is not uncommon to find irregular or interlocked grain. It has a fine texture and is easily polished to a high lustre. Silica can be found in the wood as well. Woodworkers should employ carbide tooling and should be prepared to keeps the edges of their tools sharp.  Machine feed rates might have to be adjusted to deal with irregular grain patterns.  
The wood is oily, another trait shared with the rosewoods. These oils, in conjunction with the colour pigments, yield a wood that is very durable. The compounds in the oils impart a resistance to fungi and other elements that promote decay. On the other hand, Pau Ferro's oiliness can interfere with gluing and finishing. Woodworkers will have to utilise various techniques to deal with this aspect. These techniques vary from wiping surfaces to be glued with acetone to using epoxy as a glue.
The wood is stable when dry; however, it is tricky to dry without degrade and surface checking. Woodworkers should be aware of the wood's moisture content upon purchase. Wood that is air dried may need further seasoning before use.

Pau Ferro endgrain
Given its beauty and resemblance to the rosewoods, Pau Ferrro is used in many similar applications. It is popular in furniture making both as a solid and as a veneer. Its use in architectural applications can be challenging. Each tree is unique in appearance, so finding long sequences of veneer or solids is difficult. Pau Ferro is common in musical instruments, from fingerboards to guitar back and sides. It is also well suited for decorative objects such as small boxes, pens and other turnings.
Pau Ferro has another side to its personality, which all woodworkers should be aware of. Although uncommon, this species can produce sudden and severe allergic reactions. Individual susceptibility can vary, but caution is the word here. Contact with shavings and sawdust should always be avoided. Wearing a dust mask during all operations is required. Sensible use of all available safety practises will make working with Pau Ferro safe and enjoyable. 
With the decline of the true rosewoods and with some of them banned form trade, Pau Ferro should be in the woodworkers' purview. It is becoming a common species and its beautiful and striking appearance make it suitable for many projects. However, let's learn from the demise of the rosewoods and save this precious wood for very special occasions.
Average Dried Weight54 lbs/ft³A measure of its weight at 12% moisture and an ambient temperature of 70°F.
Specific Gravity.70A measure of the ratio of its density compared to water (at 12% MC)
ShrinkageRadial: 2.8%,
Tangential: 6.7%,
Volumetric: 9.9%
Radial (the amount of crosswise shrinkage);
Tangential (the amount of lengthwise shrinkage);
Volumetric (the total amount of shrinkage.)
T/R Ratio2.4A measure of the uniformity of tangential to radial shrinkage.
Janka Hardness1,960 lbfA measure of resistance to denting and abrasion.
Crushing Strength8,830 lbf/in²A measure of compression strength parallel to the grain.
Heart is multi-coloured often overlaid with black/brown stripes. Highly contrasting pale sapwood.
GrainStraight, occasionally interlocked.
TextureFine texture, but may contain silica.
Sharp tools required. May present gluing and finishing challenges due to presence of oils.
Furniture, musical instruments, cabinets, veneer and decorative objects.
Price$21.80/bf 4/4
$6.55/sq ft (veneer)
Photos and Specifications Courtesy of: The Wood Database