|Forum topic by EmptyWoodTone||posted 04-05-2009 07:30 AM||3004 views||0 times favorited||1 reply|
04-05-2009 07:30 AM
Hello all! I’m in need of your knowledge today. I’m in the process of learning how to make Japanese Bamboo Shakuhachi flute. And one of the first steps is to harvest green bamboo and dry it. One of the most common methods is to “roast” it over the coals, or use a propane torch to heat it up to melt the resins in the bamboo then wipe them off. Curing bamboo in this way changes its color from green to yellow and helps it not to crack in the future. But Shakuhachi flutes are still notorious for cracking, even though they were “heat treated”. So, on one of the websites I have found a method which suggests to “french fry” the bamboo:
For the adventurous, there’s an intriguing wood treatment which bypasses most of the traditional bamboo drying/treatment processes and that’s to french-fry the green culm in hot non-catalyzed tung oil. Cut the culm and drill out the nodes. Heat a tube of oil to about 350 F. Introduce the green culm. When all boiling and other activity ceases cut the heat and allow the oil to cool with the culm submerged.
Here’s what happens: All moisture is expelled as it’s turned into steam and escapes as bubbles. All lignin in the wood is hardened as the oil temperature is above its hardening point. All the surface waxes will be melted and removed. During the cool-down period any air which was greatly expanded at 350 F. contracts and atmospheric pressure drives the oil into the wood. Wipe all excess oil from your culm and submit to the standard 3 month drying period.
The result will be bamboo which has had it’s starches and sugars stabilized, all moisture removed and be thoroughly impregnated with hardened linoxyn. The wood will be markedly hardened and strengthened—being waterproof, dent proof, etc. The modulus of elasticity will drop considerably and the material will become even more rigid and ‘musical’. The major component of a Stradivarius violin is the treated wood of the top plate. It’s acoustical properties are what we recognize as exceptional sound. Once the culm has cured, craft a flute in your usual manner.
So, I have decided to try this method, but I have no clue how the Tung Oil is going to react when boiled and the biggest question is what can I boil it in and then stick a bamboo pole in this tube to fully submerge it in the oil. And this is where I need you help guys.
Keep in mind that bamboo for Shakuhachi Flute is usually bent, so the tube has to be large enough to fit all the ranges of bamboo – up to 6 inches wide (counting bends at the root part) and up to 3 feet long.
Thanks a lot.