Theatre Design & Technology - Fall 2009 - 29

Mechanical ProPerties of coMPosite Panels
Density
MOR (psi)
MOE (psi)
IB (psi)
Hardness
(lbs/cu ft)
(lbs)

Screw Holding
Face (lbs)

Screw Holding
Edge (lbs)

40-50
-

231,335
2393

250,190
398,853

58
80

500
489

247

47-50
50 to 80

2103
4500

326,300
400,00 to
800,000

500

225

60 to 80

6000

650,000 to
1,100,000

40
45-47
53-60
55

2500
3481

250,000
348,100

90
109

225
298

6000

625,000

125

250

49
38 to 42
26 to 28
20 to 31
36
32 to 38

4800
3500
750-1000
400
3400
3,000-7000

500,000
439,667
86,000

125
80

250
230

650,000
1,000,000 to
1,900,000

225

Formaldehyde
Max. Emissions
.20 ppm
.20 ppm

202

Source
ANSI 208.1
Wood Handbook, 10-18
roseburg.com
FPLRN-077 (Forest Products
Lab Research Note #077)
FPLRN-077 (Forest Products
Lab Research Note #077)

200
225

.30 ppm

205

none

Flakeboard.com
ANSI A208.2
plumcreek.com
plumcreek.com
plumcreek.com
Phenix Biocomposites 4
homasote.com
aknightcompany.com
osbguide.com
Wood Handbook

230

notes: non-structural data for comparison only. Does not represent engineering design values.
* 1. Where possible, data presented is that of materials commonly available at local lumber yards. * 2. w˝ basis, unless noted. * 3. Based on ANSIA208.1,
Grade M-3; this data not specified under Grade PBU * 4. Phenix Biocomposites is now known as Environ Biocomposites, Mankato, MN. As of publication,
Environ is the only active manufacturer of Wheat Straw board * (Blank = data either not available or not published.)
most underutilized composite available to the performing arts industry. Particleboard has a bad reputation because it is prone to edge chipping and can
possess an undesirable surface texture. Its high density produces heavy but
durable panels that are very low in cost. For manufacturers to obtain particle
board with good strength and smooth surfaces, they incorporate particles
with a high degree of slenderness (long thin particles). [Wood Handbook:
wood and an Engineering Material, 10-16, 1999, FPl-GTR-113].
Given that "particle size and geometry, particle distribution between
core and face layers of the panels, type of resin, and board density are
some of the major parameters affecting both the physical and mechanical properties of panels [Hiziroglu, Introduction to Wood Properties
and Products], it is not surprising that considerable research is being
conducted to improve the properties of particleboard for a wide range
of applications. Residential stair steps comprised of particle board are
readily available. Promising advances in manufacturing are introducing
particleboards with considerably finer surface texture, such as SkyblendTM
by Roseburg Forest Products. The current trend in particleboard manufacturing research is working towards multi-layered panels with average
and larger-than-average sized particles in the panel's core with very small
fibers in the face layers. This produces a panel with a surface smoothness
approaching that of Hardboard, but at a lower density creating a lighter
weight panel ideal for underlayment and also for industrial furniture
where printed-paper laminations are common.
It is important to know that, unlike plywood or OSb, all other wood
composite panels are manufactured to true thickness. A ¾˝ think sheet
of particleboard really is ¾˝ thick, verses a comparable sheet of AC ply-

wood which is 23/32˝ thick. Additionally, it is surprising to note that
particleboard is less susceptible to warping and overall deformation that
plywood, and the clean sharp edges and low cost of particleboard make
it an ideal stage floor underlayment and a fine choice for non-structural
scenery applications.
Fiberboard

Fiberboard encompasses several products including fiberboard insulation, medium-density fiberboard (MdF), and hardboard (commonly
referred to by the trade name Masonite). MdF and hardboard are covered below. Generally speaking, fiberboard refers to a wood-fiber based
low-density insulation board. Interestingly, fiberboard is the oldest woodbased composite. Often referred to as sound board, and also as the trade
name Celotex, Fiberboard was developed in the 1900s as an insulation
material and was used extensively in housing construction as a sheathing material until the mid 1960s when rigid foams began to take over
the market. Today, fiberboard products are found largely in acoustic ceiling tiles and as a one-half inch insulation panel widely available at local
lumber yards and home improvement stores. Fiberboard has an average
density of 15 lbs./cu. ft, to 30 lbs./cu. ft making it very light weight and
easy to cut with a matte knife.
To manufacture fiberboard, wood and wood waste materials are
processed to a pulp-like consistency. This process develops the natural
lignin in the wood which provides almost all of the adhesive necessary
to hold the fibers together. The lightweight and low density allow fiberboard to be thought of as fibrous sponge filled with air pockets. It is these

2009

theatre

design

technology

http://www.roseburg.com http://www.Flakeboard.com http://www.plumcreek.com http://www.plumcreek.com http://www.plumcreek.com http://www.homasote.com http://www.aknightcompany.com http://www.osbguide.com

Table of Contents for the Digital Edition of Theatre Design & Technology - Fall 2009