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1 Millage Thickness?
This leads us to the final question which is: “Why 1 millage thickness”?
That amount, which is 1/1000th of an inch, is the standard that the Coating
Industry has established. By agreeing to a fixed standard, the coverage of
any coating can be calculated and compared. What determines that coverage
is the volume solids. The volume solids define the physical limits of coverage
and the standard that determines that limit is the 1 millage thickness yardstick.
SUMMING IT UP
In conclusion, by using a nonporous surface and a 1 mil thickness as the fixed
measure, the playing field is now leveled because the inconsistencies of a
wood surface and the physical variations between different stains are effectively
neutralized.
FIGURING IT OUT
The volume solids of a coating, a non-porous surface, and 1 millage thickness
are the scientific tools that will provide the consumer the objective standard
they need to compare the coverage and cost between different wood stains.
These tools are brought together in the simple mathematical formula:
16.03 X each 1% volume solids = the square foot coverage of one gallon of
a given coating over a non-porous surface.
HERE’S HOW IT
WORKS:
EXAMPLE
“X” Wood Stain has 18% volume solids. “X” Wood stain costs
$75.00 per gallon
“Y” Wood Stain has 38% volume solids. “Y” Wood Stain costs
$45.00 per gallon
“X” Wood Stain
1 coat coverage claims are 350-450 square feet per gallon.
“Y” Wood Stain 1 coat coverage claims are 200-250 square feet per
gallon.
“X” Wood Stain’s
actual coverage at 1 mil thickness over a nonporous surface is:
18 X 16.03 = 289 square feet per gallon.
“X” Wood Stain’s true cost is: $75.00 ÷ 289 = 26¢
per square foot.
“Y” Wood Stain’s
actual coverage at 1 mil thickness over a nonporous surface is:
38 X 16.03 = 609 square feet per gallon.
“Y” Wood Stain’s true cost is: $45.00 ÷ 609 = 7¢
per square foot.
THE REAL WORLD
In the real world, coverage over wood is not this precise. One gallon is one
gallon and the square foot area covered between two different stains, in most
instances, is similar even though the volume solids between the two products
vary. Typically, one gallon of any wood stain applied over a bare wood surface
will have a one coat coverage of between 250-350 square feet per gallon. Real
World Coverage is not as closely tied to volume solids as it is to the applicator
and the method of application (spray or brush), the physical properties of
the stain (its thinness or thickness), and the nature of the wood coated.
The area where volume solids do play a critical role is in the amount of stain
deposited on the wood surface. Consequently, the difference in coverage between
a 17% solids and 38% solids wood stain may be minor but the differences in
the amount of stain material protecting the wood surface will be much more
significant. 300 square feet per gallon of a 38% solids stain will leave considerably
more material on that surface than the 300 square foot per gallon coverage
of the 17% solids stain. If examined under a microscope, the film of the lower
solids stain will be more than 50% thinner than the higher solid stain even
though the coverage is similar.
It should be evident by now that things don’t always appear as what they seem. My purpose for addressing this subject is to reveal what lurks below the iceberg. Most of us only see the tip and this certainly applies to more than just a topic regarding wood stains and coverage. But if my explanation of this subject will help you as a log home owner make a more informed and intelligent decision when it comes to choosing a wood stain, then I have done my job.
Michael McArthur
Sales & Marketing Mgr.
The Continental Products Co.