Composite Panels in Stage Scenery

1. Composite Panels in Stage Scenery USITT Toronto, 2005

2. Composite Panels in Stage Scenery Panel John Hunt Research General Engineer, Forest Products Laboratory Patrick Immel Assist. Prof. of Scenery & Lighting Design Northwest Missouri State University Paul Brunner Assist. Prof. of Technical Production Indiana University South Bend

3. In this session… • Define & classify wood-based composite panels commonly used in stage scenery • Compare properties …informed decisions • Discuss stage floor applications (Patrick) • Examine the effects of moisture on composites (John) • Touch on new trends in composites • Wheatboard • Q & A

4. 5 Categories • Plywood = structural • Oriented Strand Board (OSB) = structural • Particle Board = non. • Hardboard (masonite) = non. • Fiberboard (sound board) = non. Particle and Fiber based panels

5. Some facts about composites, APA Forest products industry accounts for about 15% of forestland ownership…it is also responsible for 41% of replanted forest acreage yearly…about three million trees EACH DAY. (APA) Each year, 27% more timber is grown than is harvested… (APA)

6. Some facts about composites The forest products industry does not want to go out of business. They want to get the most out of their raw materials, which fuels continuing research into composites. Consumers want environmentally friendly products, but only if they are inexpensive.

7. USITT Conf. 2001 Long Beach #2 Informal survey during a session, 80 members of the institute… Cost was the most important factor governing material choices. Of these respondents, 75% said they use plywood instead of OSB in platforming...YET, at the time OSB cost 15% less based on nat’l price data for ’01.

8. Why composites? • “Green” construction material • Small diameter timber • Dimensionally more stable, largely because moisture content is closely monitored during manufacturing • Variations in adhesive and particle size produce wide range of custom products • Low cost-of-manufacturing = low end-user cost

9. Physical Properties

10. IE – Internal Bond force that it takes to pull a material apart, perpendicular to its face 2” by 2” specimen…measured in psi. Improved with careful balance between proper adhesive selection, and the % of adhesive to particles in manufacturing Physical Properties

11. Physical Properties MOE – Modulus of Elasticity The ratio of stress to corresponding strain on a sample, below its elastic point. • controlled primarily by individual particle stiffness, and to a lesser extent by the adhesive used in the panel • Of critical importance in structural composites

12. MOR – Modulus of Rupture Measure of strength at the instant of failure adhesive used in the panel generally controls the MOR Physical Properties

13. Physical Properties Hardness • Dent resistance of a material • Relates directly to durability of the surface

14. Density Profile Not typically published, but important factor to understand “U” shaped density gradient High-density on composite panel faces mimic the flanges of an I-beam Think of stress-skin platform design using I-beam design Physical Properties

15. Density Gradient

16. Figure ‑1 Image of wheatboard's three-layer construction. A 5-layer panel

17. Properties • Use properties to compare your currently used materials with new products • Help you make more informed decisions…research.

18. Dig up more information… • American Plywood Association • American Wood Council • Forest Products Society • Forest Products Laboratory • Wood Handbook • Composite Panel Association • Manufacturers mypage.iusb.edu/~pbrunner/