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Measuring moisture content above fiber saturation

Publisher
Corvallis, Or. : Western Dry Kiln Association
Publication Date
Keywords
  • Lumber -- Moisture

Abstract

MEASURING MOISTURE CONTENT ABOVE FIBER SATURATION Uli Heimerdinger Lignomat USA Portland, OR WHY WE NEED TO MEASURE THE MOISTURE CONTENT IN WOOD EMC varies by location, such as West Coast, Southwest, East Coast, Southeast, Europe. Figure 1 shows the recommended final moisture content for furniture. If the moisture content changes after a product is assembled, situations can arise such as those in Figure 2. Figure 2. Moisture changes after a product is made results in shrinkage and pieces that don't fit. 89 Moisture content also varies by usage. For example, door and window stock should have a higher moisture content than wood for furniture. Determine the moisture content in the kiln for moisture content-controlled schedules. Figure 3 is an example of such a schedule. ,schedules Edit Help Date: 04127794 Operfater: BO Schedule type: DM Species: 28 - Spume Description: A muddied gook OM schedule Fie Aevetsing EMC • F Hauls Spared % A B Heathy up 12.4 120 in() 3:00 3:00 Weaning Oyu 12.2 130 5 100 3:00 3:00 Cowing - MC/C ) GO 12.2 130 100 3:00 3:00 MC%. 55 11.0 130 45 3:00 3:00 50 18.0 130 100 3:00 3:00 45 9 0 130 100 3:00 3:00 40 7.8 130 100 3:00 3:00 35 6.6 130 100 3:00 3:00 30 5.6 140 100 3:00 3:00 25 5.0 148 100 1011 3:0111 20 5 0 150 100 3:00 3:00 15 5.0 160 inn 100 3:00 10 3 . 4 160 100 3:00 3:00 5 3 4 160 ign 3:00 3:00 r nnellitinotiren / A 1 MI 17 1 MI . 11111 /.nn Figure 3. Example of moisture content-controlled drying schedule. Determine shut-off point of kiln. Conduct quality control after drying (in-line meters). Presort lumber. MOISTURE VARIABILITY Variability Occurs From board to board, for example in heartwood and sapwood. Within board wet pockets over the length of a board over depth of board (see Figure 4). Within lot different air drying time seasonal species Drying rate varies with Sawing pattern, flatsawn boards dry faster than quarter sawn Location in the kiln Uneven airflow along length and height of kiln Uneven airfl

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