The Heinrich Cane Density Test

Purpose:
To obtain a number describing the approximate density of a piece of cane. This test is an excellent method to assign a density, which equals stiffness, to a piece of cane. This test was developed by Mr. Jean-Marie Heinrich of Mulhouse, France.

Materials needed:
1. balance, accurate to a hundredth of a gram
2. pycnometre, to weigh the cane relative to water (see photo below)

Procedure:
1. Weigh the cane alone
2. Weight the cane with the pycnometre filled with water
3. Weigh the pycnometre with the cane in the pycnometre

Computation:
M= weight of cane
M1=weight of cane plus pycnometre filled with water
M2=weight of pycnometre with cane in water

Formula: Density=M / (M1 - M2)

Example:
M, cane alone= 1,30 grams
M1, cane with pycnometre filled with water= 218,13 grams
M2, cane immersed in pycnometre = 216,05 grams
1,30 / (218,13 - 216,05)
1,30 / 2,08 [divided by] = a density of .62

Notes:
1. The density of water is 1. The higher the number, the more dense is the cane. For example, cane of a density of .61 that works very well for modern bassoon reeds is denser than the cane that I use for Baroque bassoon reeds which has a density of about .45.
2. The test should be done with cane only split, not gouged or profiled. For the test to be accurate, there has to be as much material as possible to weigh and displace the water. This is especially true considering the porous nature of the cane. For example, if gouged, shaped and profiled cane were tested, the numbers would to too close to be accurate using this equipment recommended here. A much more accurate balance and a smaller pycnometre would be needed.
3. The density of a piece of cane has a strong correlation with the stiffness. In other words, cane with a high density is stiffer than cane of low density.
4. The number obtained is an approximate average density of the entire piece of cane. Different sections and different layers of the piece of cane will have different densities.
5. The test should be done as quickly as possible, another test of the same piece of cane cannot be done immediately. To retest a piece of cane, it is necessary to wait until the cane is again dry.
6. The pycnometre can be purchased from:

Etablissements Special Verre
17, rue Forlen
ZI Forlen
67118 GEISPOLSHEIM/Gare
France

Etablissements Special Verre is the only firm that I know that will manufacture a pycnometre of the dimensions needed to test bassoon cane. I use a pycnometre that will hold a piece of cane 150 mm long. The cost of a pycnometre is about 160 Euros.
7. The balance can be purchased from any laboratory supply service such as Fischer Scientific. I use a balance made by Denver Instrument Company. The cost of a balance accurate to a hundredth of a gram is about $250.

Pycnometre manufactured by Etablissments Special Verre