Internal construction of signs
In a second strategy, commonly called “Press Thru Letters”, the letters cut from the aluminum face. Acrylic letters are cutout a little smaller to fit thru the eliminated aluminum. The thickness of the acrylic letters will certainly range from 1/2″ thick to 1″ thick. The acrylic letters are then merged to a backup acrylic sheet, and the backup sheet is then connected to the back of the aluminum face so that the letters push thru the cutout areas.
Bronze/ Brass. Bronze and brass are primarily alloys of copper and zinc, plus traces of other metals, in differing proportions. They can be cast from ingots, sawn from sheet material or extruded. Smaller sized sign fabricators are generally restricted in the size of sections that can be poured. Their bright surfaces can be preoxidized by chemical attack or can be left to oxidize naturally in the weather condition. If oxidization is not desirable, manganese can be included to the alloy and the surface can be maintained through such finishes as lacquers or liquid plastics.
Red brass is an alloy of 84-86 percent copper and 14 percent zinc.
Yellow brass is an alloy of 70 percent copper and 30 percent zinc. Brass accepts chrome plating much better than bronze, and is therefore preferred for that purpose.
Casting. Cast metal signs are strong, one piece signs or individual letter forms of a reasonably heavy gauge. They are soften used when toughness or prestige recognition is required.
Installing. Metal signs are mounted with metal-rod wall fasteners, numerous adhesives, or by welding, brazing, or soldering onto a metal surface.
Fabrication Process. A paper pattern is made and connected to a metal plate. Following the pattern, the sign is eliminated with a band saw. Any metal is usable that can be sawed. Stainless-steel, for example, can be utilized up to a density of about 1/8 inch (.3 millimeters) or aluminum approximately 1/2 inch (1.3 millimeters).
Finishing needs only the removal of any rough edges by belt sanding and filing. More treatment might involve enameling, plating, or anodizing. Wall accessory strategies are basically the exact same as those for cast metal signs.
Producing Sheet Metal. Made sheet metal signs are hollow, thin-walled three-dimensional signs. They are built by hand from many different pieces. Sides and face of the sign’s are flat and generally broad in location. Numerous sheet metals such as stainless-steel, copper, or aluminum may be made use of.
Fabrication Process. A paper pattern of the signface is connected to the metal and the types are cut out. These types are given depth with the addition of sides. Sides and face are seamed by either soldering for steel, heliarc welding for aluminum, or brazing for copper. Size constraints for this kind of sign are really flexible and can grow to 10 feet (3 meters) in overall length. The surface of the sign can be completed by polishing, plating, anodizing, or enameling.
Internal construction of signs, particularly of illuminated ones, is a specialized art. Internal structural members must be engineered to allow space for electrical equipment, accessibility for relamping, and so forth. Because of the complexity of these construction problems, sign fabricators are best qualified to solve them. However, the exterior structure of any sign is the concern of the designer. In most cases the fabricator can build the exterior structure exactly as shown on the final design documents. If the designer has doubts about the strength of any structure he has designed, he can ask a fabricator to evaluate it, using accepted structural engineering methods.
If the designer conceives of a very large or unusual sign structure, it may require extensive engineering studies, which are too much for the consultant fabricator to do on speculation. It is advisable in such cases to hire a licensed structural engineer on a consultant basis who can provide calculations and structural drawings that will be issued with the designer's working drawings. Such a consultant would also supervise fabrication and installation of the structural work he has engineered.
The exterior sign system for McCarran International Airport involved several large signs which required the services of a consultant structural engineer. This engineer worked closely with the designers, checking the strength of each design as the development work proceeded. Basic problems and solutions that came from this collaborative effort are outlined in the following case study.
To demonstrate the process of design development with actual sign problems, the following examples of exterior and interior signs were chosen from the authors' own experience:
Exterior Signs: McCarran International Airport
In this example, existing conditions influenced the design studies and ultimately the final solution.
- Strong desert winds of up to 80 mph often carry sand. Wind may blow signs over or blow out plastic signfaces. Sand may sand-blast the signs' finish.
- Signs in parking area are vulnerable to damage by carelessly driven vehicles. Tipsy drivers abound.
- Multilane circulation road requires signs to span up to 45 feet (13.5 meters).
- Major identity sign at site corner should be tall and visually strong. Engineering problem indicated because of strong winds.
- For sign panels consider alternate materials and methods to avoid plastic signfaces:
- Steel sign panel with vinyl copy.
- Alternate: aluminum panels with cutout aluminum copy.
- For sign supports consider alternate methods and materials:
Thin metal enclosure over heavy steel pipe inner frame.
- Alternate: heavy structural square, round, or rectangular tubing to serve as both inner and outer frame.
- For multilane road signs investigate the following:
- Freeway-type sign structure with truss spanning between vertical pipe supports.
- Alternate: special support structure of heavy wall pipe with elbows connecting vertical supports to horizontal member.
- For major identity sign study honeycomb core aluminum panels for signface with porcelain enamel finish, as used on freeway signing. Consider major identity sign to be 50-foot (15-meter) tall square tower:
- Steel frame with attached porcelain steel sign panels and silk-screened copy.
- Alternate: honeycomb panels as used on freeway signs over structural steel frame, with attached cutout copy.