Jim Hingst reviews the history of hardboard, how it is made and Scooter Board, the next generation of hardboard.
A sign maker had asked if he could mount a printed vinyl graphic to Masonite, which is another name for hardboard. Because hardboard is porous, I told him to either paint or varnish the sheet to prevent it from absorbing moisture which could adversely affect the adhesion of the graphics. A better answer is to use a product called Scooter Board™, which is a hardboard with a water-resistant urethane coating. (I’ll tell you more about Scooter Board at the end of this article.)
“For most outdoor sign applications, hardboard
is a poor choice if you want a long lasting sign,” says pinstriper John “Tramp”
Warner of One Shot. “The best use for hardboard is indoor signage and cut outs
for wall graphics. I only use tempered
hardboard. I buy it already coated out. Then I scuff it, wipe off the dust and
give it a coat of One Shot. It’s like
glass to work on.”
Even
though a board may be coated, Warner advises to recoat it with one to two coats
of One Shot lettering enamel using a foam roller. This extra step prevents the background from
fading out. “Recoating your boards
ensures that your sign will last in the elements. If you don’t recoat your
boards, they’re likely to turn brown within three years. As I like to say, ‘there
are no shortcuts to quality and value.’”
What’s in the "Hardboard" Name?
What
most people call Masonite is more correctly called hardboard or hardwood board. Masonite is a brand name of the Masonite
Corporation for a hardboard product, appropriately named for the person, who
invented this type of hardboard in 1924, William Mason. Although the name is still used and the
company is still around, the Masonite Corporation closed its last hardwood
manufacturing plant in the United States a couple of years ago. Masonite may
not be available, but similar hardboards, such as Duron are.
To
set the record straight and give credit, where credit is due, hardboard was
actually invented nearly thirty years before Masonite was developed, in the
late nineteenth century. Englishman
Daniel Manson Sutherland is credited with the invention. The fickle finger of
fate, however, favored Mason and not Sutherland. Because
Masonite was the first brand on
the market in the US, the name stuck.
Mason
made the original “Masonite” hardwood
boards by subjecting wood chips to steam. After softening up the chips with
steam, the wood is shredded so that all that is left are the fibers. The slurry of fibers is spread over a screen,
which helps drain the water from the mush. The remaining water is squeezed and baked out
of the sheet in a press. In this
process, temperatures reach at least 350ºF. This high heat not only turns any water to
steam, but also fuses the ingredients together. Because the original wet
process hardboard is made on a screen, the sheet is smooth one side (S1S). The other side of the sheet has a rough
texture. The wet process hasn’t changed much since the days of Mason.
The
original wet process “Masonite” panels used no glues or resins to bind the
fibers together. The product was completely natural and only uses the raw
cellular material in wood itself. By today’s standards wet process hardboard is
“eco-friendly”. Wood fibers are composed of cellulose, which comprise the cell walls
of wood and a material called lignin, which is a binder that hold the walls of
a cell together.
After soaking the wood
fibers, the cellulose and lignin are reconstituted into a sheet. No other
binders are added. Only the lignin of the wood fuses the fibers
together under heat and pressure. As the hardboard is pressed, water is forced
from the sheet, and the board is squeezed to the desired density and thickness.
The
long wood fibers of hardboard give it its strength. The strength also comes
from the fact that the fibers are not oriented in any particular direction.
Rather, the fibers are pressed together randomly. That intertwining of fibers
does a better job of holding the sheet together than if the fibers were
arranged in a single direction. Nevertheless, as strong as hardboard is, it
does not have sufficient structural strength for many building and signage applications…certainly,
no where near the strength of plywood.
These
sheets derived the name “hardboard” because the manufacturers use hardwoods,
such as oak, aspen, maple and birch to make the panels. “The
name ‘hardboard’ is well-suited,” says Jim Graham, president of Woodcraft
Manufacuturing Co. “It’s one hard board. Although it’s made from wood, it’s
more dense and a lot tougher. It’s
tougher to saw; tougher to drill; and tougher to nail.” Some people may view
that toughness a shortcoming. Graham feels that hardboard’s toughness is its
best attribute.
While
hardboard is made from wood, it doesn’t have all of wood’s characteristics. There are no knots. No grain. No sap. And no
variation in strength and consistency from one tree to another. Compared to wood, hardboard is generally more
moisture resistant; its surface is smoother; and it’s more impact resistant.
Its uniform density also makes it less prone to warping.
Conceivably
hardboard could be made from any type of plant material. So why not use
cheaper, more abundant and easier to process softwoods, as pine? Graham says that the reason is that softwoods
contain high amounts of resins that can stain a painted surface. Softwood fibers also are softer and tend to
crack.
The wet
process isn’t the only way to make hardboard. “Later a dry process was
developed,” says Graham. “There’s also a wet-dry process. Each manufacturing
process is different and the finished products are different, too.”
Along
with developing a wet process for making his Masonite, William Mason also
invented a wet-dry process. Both
processes are similar. In the wet-dry process the wet mat of fibers is
pre-dried before the sheet is pressed.
Temperatures are also higher, reaching more than 400ºF. The end result is also different, because
this process produces a board with two smooth sides (S2S).
As
the name suggests, dry process hardboards do not use water in manufacturing.
Instead, wood fibers are dried and fluffed up.
Dried fibers are blown into a large box to form a thick mat. To help
bind the fibers together, synthetic additives are added to the mix.
Whereas
as the wet process arranges the fibers of a sheet in two dimensions, one layer
of fibers on top of another, the dry process arranges fibers randomly in three
dimensions. To make a board with two
smooth sides (S2S) the fibrous mat is squeezed in a press between two hot
plates.
Each
manufacturing process has its own advantages.
Hardboard produced using the wet and wet-dry processes is very flexible
and accepts paint well. Hardboard
produced using the dry process is stiffer and has better internal
strength. Because fibers are arranged in
three dimensions, it is less likely to delaminate.
Tempering Hardboard
To
toughen the hardboard up a little, manufacturers have added resins, waxes, and
other goodies, such as oil. The oil acts
as a binder, which makes the sheet stronger and more moisture resistant. Sheets without these additives are called
“untempered”. Hardboard with these
additives are called “tempered”. Regardless of whether a hardboard is
manufactured wet or dry, the sheet can be “tempered”.
In the tempering process the boards are heat treated. Subjecting the board to heat creates a
stronger bond and further compresses the sheet.
Tempering the hardboard hardens
the surface, making the sheet more abrasion and scratch resistant and less
prone to warping. It also makes a more dimensionally stable sheet, which is
more moisture resistant.
Painting hardboard
In the
manufacturing process, oil, such as tung oil, is applied to the surface and
then the sheet is baked in a recirculating oven. The oil slightly penetrates
the surface of the sheet and what is left is flashed off in the bake cycle.
Contrary to popular believe, no oil residue remains on the board. So there’s no
surface contaminant to cause paint adhesion problems.
“Treating
the board with oil makes the more sheet
more paintable, because the treatment improves the hold out of the paint,” says
Jim Graham of Scooter Board. “Otherwise, the board would soak up the paint like
a sponge.” The term “hold out” means that the finish coats of paint do not soak
into the primer or the board itself. Poor paint hold out results in an uneven
blotchy finish.
If
you are going to use hardboard as a sign blank, you need to treat it with a
little TLC…if you want it to last.
Here’s how. Before you do any sanding and painting, you must clean the
hardboard. “Never clean hardboard with
detergent and water,” cautions Scooter Board’s Jim Graham. “Water will just
raise the grain of the sheet.”
To prep
the surface of the hardboard, Graham recommends either wiping the surface down
with a clean rag or tack cloth or quick wiping the surface with a rag dampened
with a solvent. Take the time to clean the surface properly. Poor surface
preparation is a leading cause of paint failures.
After
cleaning, the next step is to lightly sand the smooth, glossy side of the sheet
using 600-grit sandpaper. Scuffing up the sheet will give the surface some
tooth for the paint to bond to. Failure to sand the smooth, hard surface can
result in paint adhesion failure. Next, take a damp cellulose sponge and wipe
off any dust and particles.
You
can paint hardboard with either an emulsion or oil based paint system or with
lettering enamels. If you are using a
sign enamels, such as 1-Shot Paint, you can prime the sheet with thinned
lettering enamel. With other oil based paints use the manufacturers recommended
primer. When using an emulsion paint you can also thin an exterior grade paint
with water at a 1:1 ratio and use that as a primer.
Regardless
of which paint you use, prime the surface with at least one coat of primer.
Priming is an absolute necessity. Failure to prime the surface can result in
the wax in the board bleeding through and yellowing the finish coat of
paint. Don’t forget to prime the edges
and the backside of the board.
After
priming, lightly scuff the surface with 600-grit sandpaper and finish the job
with one to two coats of paint. If you are using an emulsion or water based
paint system, two coats are recommended.
If you are painting with an oil-based paint, coat the rough backside of
the sheet to prevent bowing of the board.
If
the sheet is used for outside application, be sure to coat the edges of the
board to prevent moisture absorption. Coating
the backside of the sheet is always a good idea for exterior applications. Failure to do so may result in moisture
penetrating the sheet to the paint layer. Moisture under the paint will cause
peeling.
Scooter Board: The Next Generation of Hardboard
Have
you heard of Scooter Board™? It’s the
next generation of hardboard. Jim Graham
of Woodcraft Manufacturing (Dayton, KY) decided to improve on the Masonite
formula. Graham, who’s father had worked
for the Masonite corporation, well understood the pluses and minuses of
hardboard, decided to make a good thing better.
“We
use the same ‘wet process’ in making the board as Masonite did,” says
Graham. “In fact, we’re the only company
that is using the old process. But to improve the stability of the sheet, we
made a few changes to the sheet.”
In
processing, the raw materials are broken down into shorter fibers. Graham feels
that the shorter fibers are less prone to absorbing moisture and less prone to
warping than the earlier generations of hardboard.
The
major difference between Graham’s product and the original hardboard is that
Scooter Board™ is surfaced with a white urethane. The
plastic covering is fused to the hardboard core using heat and pressure. The surface of the sheet is pretty tough
stuff. It resists water, solvents and
mild acids.
Scooter
Board™ is great for screen printed signage, but you have to use the right
ink. Ask your distributor for an ink
recommendation. Graham recommends
several Nazdar inks, including the 5900 series enamel inks with no catalyst and
either the 9600 or 9700 series with a catalyst. Nazdar’s 1700UV inks are also
recommended.
The
surface of Scooter Board is tough to stick to. Nazdar makes two
catalysts for their inks: NB72 and NB80, which can improve ink adhesion.
For outdoor applications, mix 5% to 10% by weight of the NB80 catalyst
with the 9600 or 9700 inks. After the catalyst is added, shelf life of
the ink is limited to about four to six hours.
Bea
Purcell, former Market Segment Manager for Nazdar (now retired), says that the
catalyst can slow curing. For that reason “if you are printing multiple colors,
make sure that the first coat is thoroughly cured before printing subsequent
colors,” says Purcell. Nazdar’s NB72 also improves adhesion, but
it’s only for indoor applications. Purcell says that exposure to UV light can
yellow ink that has been mixed with NB72.
Before screen printing, read the ink manufacturer’s technical bulletins and “Test, Don’t Guess” prior to production. Typical tests are a cross hatch test, tape test and scratch resistance test.
While
the original Masonite may have had problems enduring the elements, Scooter
Board™ is ideal for many outdoor signage projects. “We originally thought that
Scooter Board™ would be an excellent alternative to aluminum for real estate
signs,” Graham says. “Unlike metal, our
product doesn’t dent.”
Sign makers soon
found other applications for the product, such as Point-Of-Purchase displays,
tradeshow graphics, event signage and election signs. As well as being an
excellent choice for screen printing, it’s also an ideal substrate for applied
vinyl graphics and digital prints.
Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer. Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.
Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for publications, such as Signs Canada, SignCraft, Signs of the Times, Screen Printing, Sign and Digital Graphics and Sign Builder Illustrated. He also posted more than 325 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published.
© 2015 Jim Hingst
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