is an area where advances are being made every day. The titanium
and stainless tributes really need no protective coating since
these metals are self healing and
the oxides do not alter
the metal’s color nor are
they affected by UV or environmentally corrosive chemicals. The
only issue we discovered with these metal coatings is their propensity
to scratch. We perform an extreme scratch test using a needle.
Even the protective barrier coatings will scratch. The common
denominator, at this time, with all organic coatings is that
failure is predicted when exposed to the elements. It may take
20 or 30 years, but they will
the tribute is to be displayed indoors it really needs no coating,
especially if it's framed under glass. That's recommended to
guard against finger prints or someone accidentally using an
abrasive cleaner or a gritty cloth to clean the tribute. Anything
will scratch, including diamond under the right circumstances!
the tribute is mounted on granite and framed without glass we
recommend our standard coating,
a clear fluoropolyurethane (FPU). You’re probably familiar
with this member of the fluoropolymer family - DuPont Teflon®.
Fluoropolyurethane is one of the finest coatings available in
the world. This coating, which has been engineered to withstand
the outdoor elements for 20-30 years, will protect your tribute
from finger prints and scratching. It does not yellow when exposed
manufacturers of bronze plaques, one being a very large producer,
are using acrylic lacquer to protect the metal from discoloring
oxidation. These coatings are being used on plaques destined
for outdoor display. The following quote is from the automobile
coating experts at Trinity 1945 Inc. Lacquers were used extensively
on cars in the past.
lacquer paints have been largely discontinued by most manufacturers.
Acrylic Lacquer auto paint is primarily for antique or classic
car restorations, where the highest possible gloss and shine
is desired. Acrylic Lacquer auto paints also will not have the
durability of acrylic enamels or urethane auto paints. For this
reason, we recommend the Acrylic Lacquer paints for garage kept
vehicles that see limited use. Our Acrylic enamel auto paints,
will have more durability than the Acrylic Lacquers, and will
have a slightly less glossy finish. Please also note that buffing
out the finished paint job when using Acrylic Lacquer auto paints
addition, manufacturers have strayed from lacquers because of
the toxicity of chemicals used in the compounds and MSDS toxic
chemical regulations. Lacquers cannot stand up to the severe
manufacturers are using a clear, baked on coating, probably a
powder coat. These coatings are hard and tough, but they're still organic.
They have a tendency to yellow, and they cannot be
reapplied in the field once failure occurs. In addition, some
manufacturers who offer etched stainless recommend using no coating
if exterior use for long duration is anticipated. This will hasten
the demise of the paint or dye they use to get the image contrast.
Once the color disappears the image will still be there, but
observers will just have a very difficult time seeing it.
best coating option would bond on a molecular
level with the metal’s surface and
There are only a few clear coatings I know of that meet these
specifications. Unfortunately, most are what they call micro-coatings.
They are extremely thin, so they appear to scratch. What is actually
happening when a needle is used in a scratch test is the metal
is indented. That appears as a scratch. All other coatings are
organic or a hybrid combination which means
they will eventually
Display & Jewelry:
is a hi-tech alternative available. We located a company
that can deposit a clear, inorganic coating
via a special process. This clear coating bonds on a molecular
level with the atoms on the metal’s surface. Since these
coatings are inorganic and inert they
are not susceptible
to microbial attack or environmentally corrosive chemicals. They
are also extremely hard. To give you an example. The Vickers
(HV) hardness of 316L stainless steel is 152. The hardness test
for sprayed coatings, like the clear polyurethane on an automobile
or the fluoropolyurethane we use, uses the pencil scale. For
example, a catalyzed acrylic polyurethane has a pencil hardness
of 2H. A catalyzed modified acrylic polyurethane may have a 4H
hardness. Our fluoropolyurethane has a 6H hardness. In other
words, sprayed coatings like urethanes are relatively soft compared
to PVD coatings.
Vickers hardness test is one that measures the hardness of metals
and hard coatings. The Vickers (HV) hardness of diamond, the
hardest surface known, is 816. One DLC clear coating has a Vickers
(HV) hardness around 306. It is twice as hard as the 316L stainless
itself. It is a very hard and practically indestructible coating,
especially when used on a piece for exterior display purposes.
The draw back is that one off pieces are very expensive to coat.
ultimate coating would be a synthetic
diamond. This coating has all the properties
of real diamond including a Vicker (HV) hardness of 816. We are
working with a laboratory on
a synthetic diamond coating. If this coating, which interacts
with the surface on a molecular level, works on our metals, it
will be the coating of choice for outdoor environments. It is
totally inorganic and impervious to microbial attack. The process
is, however, very expensive and to date is only available
as a micro-coating.