Metals -
Types, Grades, Technical Data
A. PLAIN METALS
a) STAINLESS STEEL ALLOY 304
This is the metal of choice for most architectural and any decorative surfaces.
Ideal for fabrication. It is highly resistant to corrosion and therefore suitable
for outdoor applications. No protective coating is required.
b) STAINLESS STEEL ALLOY 316
It is rarely used except when its particularly strong resistance to corrosion
becomes a factor: chemical environments or similar exposures. It does not require
any protective coatings.
c) STAINLESS STEEL ALLOY 430
Not usable for architectural or other quality installations, this alloy contains
a fair amount of iron and will therefore oxidize. It is commonly used for lower
grade fabrication.
d) BRASS ALLOYS 464 - 260 - 280
This yellow metal is a copper alloy and is available in many different alloys,
having different trade names. Alloy 464 is called Naval Brass, Alloy 260 is
called Cartridge Brass and Alloy 280 is called Muntz. All 3 are very close
in color. Naval Brass in quality grades is widely available. Muntz, best known
by architects, has become increasingly scarce in recent years. It is highly
recommended to specify Naval or Cartridge Brass for decorative applications. Any brass will need to be clear lacquer coated to prevent and retard tarnishing.
It is not recommended to specify brass for outdoor applications, especially
not in hot and humid tropical or marine environments, or in non-air-conditioned
buildings in such climates.
e) BRASS ALLOY 220 (COMMERCIAL BRONZE)
Because of its trade name "Commercial Bronze," this alloy is commonly
referred to as Bronze (real Bronze does not exist in sheet form). Its reddish
color is highly attractive and can be matched with hardware in real bronze.
Again, this alloy needs to be clear lacquer coated and all other recommendations
for Brass will apply.
f) COPPER ALLOY 110
Plain copper sheets in their reddish color are very beautiful. But many of
the more complex decorative finishes can only be applied with great risk or
subsequent, residual tarnishing. Best uses for copper are full sheet oxidation
finishes and textures on metal laminates. Again, copper needs to be clear lacquer coated and all other recommendations
such as for Brass apply also for Copper.
g) ALUMINUM
This material is the most common metal on earth and it exists in many different
alloys, grades of hardness and quality. Most are suitable for the various decorative
finishes. Since Aluminum does oxidize, albeit very slowly, a protective coating
is necessary. The coating for outdoor applications is anodized, whereas clear
lacquer coatings are sufficient for indoor applications. Aluminum can also
be dyed successfully with organic dyes or coated with transparent colored coatings. Aluminum's main features are: light weight and low cost. Ease of cutting light
gauge material by conventional means; give it a much wider market for decorative
applications than Stainless Steel.
h) COLD ROLLED STEEL
This is the professional name for ordinary steel sheets; the most widely used
sheet metal in fabrication and construction. Because it is basically an iron
alloy, it needs to be particularly well protected against rust. This metal
is only suitable as a base metal for decorative applications in paint and vinyl
coatings, for example.
B. METAL LAMINATES
a) STAINLESS STEEL - COPPER - ALUMINUM - BRASS
All of these metals are widely used as metal laminates. The most common metal
is aluminum, either clear coated or anodized. A metal laminate is a sandwich of a thin metal foil bonded by glue + pressure
to a substrate of phenolic resin or similar. Or 2 thin sheets of plain aluminum
are sandwiched over a resin core. ALMOST ANY OF THE DECORATED FINISHES DISCUSSED HERE CAN BE PRODUCED ON THESE
LAMINATES AS WELL AS ON PLAIN METAL. While metal laminates are lighter, generally less expensive and easier to cut
to size than plain metals, the choice between both will depend on physical
characteristics. All major HPL distributors distribute extensive documentation on metal laminate
specs and recommendations how to handle and fabricate. |