Official Luthiers Forum!

Wow that really did darken it. Can you explain the process? I thought it was just putting the tops in a regular old oven, how do you reduce the O2? And why do you reduce O2? What is the science behind this? Too many questions?

Typically, wood is made up of fibrous cellulose and resinous lignin as well as a substance known as hemicellulose that binds these together. Old wood, in which the cellulose has crystallized, hardens in the direction of the grain. On the other hand, the amount of hemicellulose decreases, thus making it easier to remove across the grain. As it becomes harder in the direction of the grain, wood becomes softer across the grain. Materials that have properties that vary depending on direction are said to display anisotropy, which in the case of wood progressively improves sound as anisotropy increases. In other words, wood has strong characteristics, responding well when an instrument is played, extending the low range, and rapidly decaying the high range. Emphasizing the qualities displayed by matured wood resulted in the development of A.R.E.

For the A.R.E. treatment, wood is first placed in a cylindrical metal pressure vessel, the internal temperature and humidity of which is controlled as the treatment process is carried out; the pressure is changed in stages. This enables the treatment process to be undertaken in a surprisingly short time if compared with the time needed to age wood.

Of particular necessity during the treatment process is the precise control of temperature, humidity, and atmospheric pressure, as well as setting the optimal amount of treatment. The result of experience and expertise spanning many years, the optimal value settings combine the “sweet sound” of a musical instrument and durability, the wood being treated during a precisely controlled process.

Two torrefied AA red spruce tops went for $56 on eBay today. The seller is looking to see what kind of interest there is.

Alex

I jumped off the torrefied bandwagon recently because I actually noticed those exact same things myself...