Proceedings e report - Firenze University Press

WOOD SCIENCE FOR CONSERVATION OF CULTURAL HERITAGE
5.2. Test on two shellbark hickory (Carya laciniosa) boards
Two ends of two imaginary boards, having dimensions 400mm by 25mm, were drawn. Four tests were
carried out on these virtual Hickory panels. Both the initial T and the final T were taken as 21 O C. The
three shrinkage coefficients were taken as follows: tangential shrinkage = 12.6%, radial shrinkage =
7.6%, longitudinal shrinkage = 0.1%. The value of the FSP was taken as 30%. Table 1 shows the
initial and final RH values for the four tests.
Table 1: Data used for computer tests 1 to 4
Test Initial Final
number RH (%) RH (%)
1 90 20
2 20 90
3 78 0
4 78 100
The boards were virtually subjected to theoretical, extreme climatic conditions to simulate expansion,
contraction and fluctuation of the cupping from convex to concave warping. The outcome of Tests 3
and 4 are illustrated in Fig. 3.
Fig. 9 - Computer prediction – Test 3: expansion and contraction
5.3. Test on Actual Pine (Pinus sp.) Samples
5.3.1. Method
Four pine samples were selected for this test. One of the samples had a tangential grain orientation
across the width to ensure that cupping would be evaluated apart from linear changes.
The samples were dried in an oven (MEMMERT Gmbh, UE/ULE/SLE 500) at a temperature of 103ºC
to reach an EMC of 0%, and then placed on a shelve in a sealed container with deionised water to
attain a constant RH of 100%, until they reached a FSP value of 31.9%. The longitudinal face and the
end grain were scanned just after the sample was oven dried and cooled back to room temperature, and
when it reached 31.9% MC.
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