Working with Ancient Kauri

Working with Ancient Kauri

The Ancient Kauri offers an unequaled look into time, well before the last ice age. Yet because it can be shaped and worked in ways that are comfortable and familiar, we get a connection to a time in a way not found anywhere else in the world today.

It is difficult to describe exactly what the subtleties of any wood are, as they change from piece to piece and grain to grain. Ancient Kauri can be cut, shaped, sanded, and finished with normal techniques. Although the wood is similar in density to Cherry, with textures similar to Basswood and Mahogany, the Ancient Kauri is an unmatched wood to work with.


These massive trees grew for approximately 2,000 years before falling into swamps. The earth has held these logs for over 50,000 years.

The Ancient Kauri is very wet when it leaves the ground and is kept wet for its journey to the US.
Upon arrival at our facility in Northern Wisconsin, the wood is kiln-dried to a moisture content
between 6 and 8 percent.

Ancient Kauri is not an oily wood.

Ancient Kauri is in no way petrified.

Standard glues and joining practices work great with Ancient Kauri.

Frequently Asked Questions

How will my Ancient Kauri bend?

As experienced luthiers know, patience is the best tool to use.

Here are some techniques from luthiers experienced with Ancient Kauri.

Stefan Nicholas, an innovative builder of classical guitars since the early 90’s, likes to use a
veneer softener such as Better Bond Super Soft when working with Ancient Kauri. Stefan’s
method includes using a liberal application of softener, then returning an hour later and
replicating the process: letting the wood stand for another two to three hours. In the next step,
Stefan places a few sheets of paper towel on each side of the board, pressing them flat with
medium density fiberboard (MDF) and clamps; replacing the paper towel twice a day for four
days. Once in the mold, Stefan leaves the wood until moisture is void -usually seven days.

Stefan states that a liberal application over a period of three to four days will make the sides very
pliable in the mold. We have used this technique successfully as well.

John Grey, an experienced builder and innovative repair expert, reports that soaking the sides
overnight before boiling them helps the pliability immensely. Should grain lifting occur, dilute
the wood glue with one-third water (for better penetration) to stabilize lifted grain. A great tip
from John is to use a wine cork for your clamping caul as it will provide even pressure on the

Joshua Muntur, founder of Homeless Dog Custom Guitars, states that it is necessary to allow the
sides to dry completely before removing them from the forms.

What does Ancient Kauri sound like?

We cautiously approach this subject, as tone is very subjective.

Jordan Grunow, owner of over forty electric guitars notes a present upper midrange attack
supported by a well balanced and warm sustain in a solid body Kauri Telecaster.
Builders of acoustic guitars have uniformly expressed satisfaction with their instruments:

The Kauri is just magnificent and the tone is awesome! Thanks again and I will be buying some
more Kauri soon!

Do I need pore or grain sealer to finish Ancient Kauri?

Finishing Ancient Kauri does not require the use of a grain sealer.

What type of finish should I use?

Ancient Kauri will accept any of your favorite finishing methods. The wood does not have
inherent properties that would prevent you from using one product over another.

We suggest customers use the techniques that are most successful in their shop. There is no
reason to vary from your usual finishing methods.

We do suggest that you sand the Ancient Kauri to a very fine grit before finishing. Over 1000 grit
is not uncommon.

What is the specific gravity of Ancient Kauri?

The Kauri tree grew as a softwood -a conifer. However, the characteristics of the Ancient Kauri
are similar to hardwoods such as soft maple or cherry, or Mahogany

There are differences in the density of the Ancient Kauri from one piece to another, without
significant changes in outward appearance. The changes seem to be related to its location
underground for thousands of years. With no change in the color or outward appearance, the
pieces that are lighter and less dense seem to have been buried near an underwater flowage of
some sort. The pieces that are more dense seem to be from more stable ground.

There are accurate scientific measurements available for modern Kauri, but Ancient Kauri has
endured changes while underground: within one tree there can be significant variation.

It is important to note that the following data refers to research on the more modern growth
Kauri, harvested using traditional logging methods. It is quoted from Forest Products Lab Center
for Wood Anatomy Research Fact Sheet on Kauri. Due to the changes present in this 50,000 year
old wood, we do not believe this data is always accurate for the Ancient Kauri. Since we lack any
other specific scientific data, we make this available.

Weight: Basic specific gravity (oven-dry weight/green volume) 0.41 to 0.47; air- dry density 30
to 36 pcf.

M echanical Properties: (First two sets of data based on the 2-in. standard, the third set on the 2-
cm standard.)

Moisture content

Green (34)

Bending strength


Modulus of elasticity
(1,000 psi)


Maximum crushing strength


Green (15)




Green (35)

Side hardness 480 to 760 lb for green material and 700 to 870 lb at 12% moisture content.




Drying and Shrinkage: The timber is reported to season well with little or no degrade. Kiln
schedule T7-B3 is suggested for 4/4 stock (A. alba) and kiln schedule T10-D5S for 4/4 stock (A.
australis and A. vitiensis). Shrinkage green to ovendry: radial 4.2%; tangential 6.0% (A. alba).

Working Properties: The timber works easily with hand and machine tools, finishes with a clean
smooth surface; good nailing and screwing properties; good veneer peeling characteristics; paints
and polishes well; easy to glue.

Other Tips

Plan to spend extra time sanding the Ancient Kauri. While sanding to 600 grit will suffice, the
most intense color, depth, grain, and iridescent qualities come through with very fine sanding -
up to 1200 grit. Extra effort gives extra rewards, and once you have passed 320 grit, sanding
becomes more like polishing and you can move through the grits quickly.

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