Claro Walnut | Canadian Woodworking

Woods To Know: Claro Walnut

Claro Walnut (Juglans hindsii)

by Peter MacSween

Mention the words Claro Walnut to woodworkers and images of large live edge table tops with Claros’ distinctive appearance come to mind. Made famous by the esteemed craftsman George Nakashima, Claro Walnut is the go-to wood for those whose aesthetic emphasizes the natural beauty of the wood. 
 
Claro Walnut has a complicated history though. The term Claro originally applied to the Species Juglans hindsii, one of two species endemic to the American west coast. It was soon found to be an excellent rootstock for those who wanted to plant walnut orchards for nut production. Trees produced by grafting European walnut on to Claro walnut were soon prodigious producers of walnuts for food and oil. In fact, it is these orchard trees that supply most of the Claro for woodworkers. Subsequent breeding experiments have produced orchard trees of a wide and varied pedigree. Today the term Claro is a general one referring to trees predominately coming from orchards.   
 
Claro is a large tree native to Northern California and Oregon. Orchard trees tend to be squat since they don’t have to compete with other trees for light. They have large crowns with impressive trunks. Trunk diameters average 3’ to 5’ with some specimens having diameters up to 9’. They typically grow between 60’ to 90’ tall.

WTK_claro-walnut

The heartwood is generally various shades of brown from tan to a deep chocolate brown. The sapwood is white and demarcated form the heart. Wood from grafted trees display a spectacular variegated, marble like appearance with grays, purple and red overtones. The grain is usually straight but figured grain is often present, including curly, crotch and burl. It has a medium texture with a natural lustrous sheen to it. 
 
Like Black Walnut, it finishes well no matter what techniques are used. It is semi-ring porous so some may want to fill the grain. Given its beauty, oil finishes are best at showing the beauty of this wood. Staining is out of the question. 
 
I have never come across Claro Walnut as lumber, although it may exist closer to its natural range. Most woodworkers will see it as large sawn slabs, blocks and squares for turning, musical instrument materials, gunstocks and veneer. It is very stable when dry and is considered a durable. 
 
If you are planning on tackling a large slab, here are some basic pointers. These slabs are often bigger than most machines, so surfacing and milling pose a problem. The most common method of dimensioning Claro involves a router mounted in a carriage that slides on two parallel rails. This McGyvered milling method is often home made. Consecutive passes can be made until the side is flat. Then the slab can be flipped over and the process repeated. 
 
Defects can be filled with epoxy or patched. Splits are commonly bridged with ‘bowties.’ These are pieces of wood that are inlayed into and also span the cracks stopping them from progressing. Bark is usually removed since it will eventually fall off anyways. The purpose here is to highlight and present the wood in the most natural way. 

WTK_claro-walnut-endgrain
Claro Walnut End-Grain
 
It's important to pay attention to the woods moisture content. The large slabs must be air-dried and any attempts to speed up the process by using a kiln can be disastrous. Patience is the key here. Remember to finish all sides equally to allow even migration of moisture in and out of the slab.  These slabs will continue to move with the seasons. The movement must be built into the design, especially as it pertains to the table supports. Work methodically and you will be rewarded with a one-of-a-kind piece. 
 
If working a full slab is not possible, you can usually find Claro in smaller pieces. It turns very well lending its distinctive appearance to all sorts of turned objects. Guitars made from Claro backs and sides are very beautiful although there is some debate about its acoustic qualities. 
 
Unfortunately, Claro is expensive with the highly figured and multi-coloured pieces commanding top dollar.  Starting out with smaller pieces can be you entry into the world of Claro. It’s a joy to work with and has an impressive pedigree. I highly recommend it to woodworkers of all skill levels. 
 
 
Average Dried Weight40 lbs/ft³A measure of its weight at 12% moisture and an ambient temperature of 70°F.
Specific Gravity.64A measure of the ratio of its density compared to water (at 12% MC)
ShrinkageRadial: 4.3
Tangential: 6.4
Volumetric: 10.7
Radial (the amount of crosswise shrinkage);
Tangential (the amount of lengthwise shrinkage);
Volumetric (the total amount of shrinkage.)
T/R Ratio1.5A measure of the uniformity of tangential to radial shrinkage.
Janka Hardness1,130 lbfA measure of resistance to denting and abrasion.
Crushing Strengthn.a.A measure of compression strength parallel to the grain.
Colour
Heartwood can range from a lighter pale brown to a dark chocolate brown with darker brown streaks. Color can sometimes have a gray, purple, or reddish cast. Sapwood is nearly white. Wood from orchard trees that have been grafted with English Walnut (Juglans regia) may have a colorful/streaked appearance near the graft, which is sometimes referred to as “marbled Claro Walnut.” Can occasionally also be found with figured grain patterns such as curly, crotch, and burl.
GrainStraight, but can be irregular.
TextureMedium.
Workability
Typically easy to work provided the grain is straight and regular. Planer tearout can sometimes be a problem when surfacing pieces with irregular or figured grain. Glues, stains, and finishes well, (though walnut is rarely stained).
Uses
Furniture, cabinetry, gunstocks, musical instruments, veneer, turned items.
Price$30.00/bf 12/4

 
  
Photos and Specifications Courtesy of: The Wood Database