A Beacon of Sign Knowledge
Rule No. 1 when lighting a sign: Make certain the sign is worth lighting. A bad concept or poor fabrication cannot be rectified with light.
With that off my chest, I focus on a double-sided, illuminated monument sign that my company, ARTfx (Bloomfield, CT), recently designed, fabricated and installed for Lighthouse Surgery Center in nearby Hartford. We started with a logo I co-designed with long-time ARTfx veteran, Paula Hansen. Submission No. 1 immediately gained client approval, which led to the sign design, a composition based around the logo and the building architecture. Again, the initial submission received an instant thumbs-up from our client and, more notably, from their rather discerning architectural firm. When I started in the sign business 43 years ago, back-to-back “slam dunk” design approvals would have been less likely than my making a hole-in-one while blindfolded in a blizzard.
ROUGH IT UP
The sign for Lighthouse Surgery Center was fabricated of .125-in. aluminum plate, but finished to match the building using ARTfx proprietary techniques, which approximate variegated limestone and stained-teak hardwood. The lighting and lettering style, commonly known in the trade as “stencil cut/push through,” simply describes metal signfaces cut through to allow for translucent acrylic letters to be inserted. In this case, the logo and letter fronts are opaque, so light emits solely from their sides.
When deciding on the type of acrylic for smaller letters or interior displays, we typically use ½-in.-thick 7328 white if letter faces are translucent, or ½-in.-thick 2447 milk white if faces are opaque. For larger letters or much of our exterior work, we use ¾-in.-thick clear acrylic in conjunction with a 3M 70% white vinyl diffuser on the back sides (it allows 70% light trans-mission) and a translucent or opaque white vinyl appliqué on the faces (depending on whether the faces are lit or opaque).
As a note, the sides of the acrylic forms should be sanded with 320 grit to promote greater light diffusion. And if the design permits, the signface itself should be finished in low-luster paint. Often forgotten by sign manufacturers, matte surfaces enhance light and facilitate its projection. The Lighthouse sign has an intentionally rough finish – perfect for showcasing haloing or washed light.
Our push-through letters feature a .080-in.-thick perimeter flange around the back sides, so they can’t fall forward. The flange width varies depending on character size and kerning, but should allow for mechanical fastening via studs welded to the back of the signface. Additionally, the application of a continuous-clear silicone bead between flanges and the face, as well as around the flanges, provides stronger letter adhesion and a means of preventing dirt accumulation and water leakage. With this method, remember to deduct the flange depth plus the thickness of the metal being penetrated to determine the remaining exposed-letter side depth. Half-inch acrylic will yield approximately .295-in. letter sides. For ¾-in. stock, increase the equation by 1/4 in.
The logo and letters manufactured for the Lighthouse sign are ¾-in.thick and detailed as previously described. However, these particular push-through forms were outfitted with .188-in. brushed stainless steel (alloy 316) fronts. It’s good to know that .188-in. stock is the thinnest stainless steel plate that can be tapped and threaded for studding through the acrylic backs to employ mechanical fastening.
A note of caution – be certain to apply white vinyl or paint to the face of a push-through letter prior to the opaque layer. Otherwise, the brilliance of light emitting from the letter sides is seriously impacted from a lack of reflectivity. Also, make certain that the inside of the sign cabinet is painted white because reflectivity disperses and intensifies the prime light source. Don’t go nuts. A coat of white primer is sufficient.
The actual lighting of a stencil-cut/push-through sign is the easy part. First, we use 5000K LEDs. Since the days of fluorescent and argon light, we have avoided 6500K. Although a sign industry standby for years, 6500K skews the light toward the cool end of the spectrum which for me, and many other light-specifying designers, introduces an artificial blue hue. 5000K registers as a neutral – toward the middle of the light spectrum, functioning as a blank canvas – pure white.
Intensity of light inside our stencil-cut/push-through signs varies between 360 and 480 lumens per sq. ft. at a distance of 4-6 in. from the face. The beam of our module diodes is typically wide, averaging 162° to 180°. We tend to use Bitro Group and SloanLED products, but there are other extremely good brands available. I would absolutely suggest using a known, leading LED manufacturer for consistency. The few times we’ve ventured from mainline brands, we’ve paid a steep price. Some of the horror stories I could tell would easily fill up another article ... or two.
One last, added lighting touch required a feat of master engineering. Our staff was able to insert a single narrow-beam, high-powered 6500K LED module into the clear acrylic side of the lighthouse graphic on the sign at the point where a beacon would be located. The beam emitted actually looks blue, and works perfectly as an alluring accent to a sign I con-sider an exemplary demonstration of many lighting, fabrication and finishing techniques ARTfx has acquired over nearly 40 years.
EQUIPMENT AND SUPPLIES
Software: Gerber Omega 6.5, gerbertechnology.com; CorelDRAW 17 X7, coreldraw.com
Router: Gerber 600 Router (for aluminum) and Gerber Saber 408 Router (for acrylic), gerbertechnology.com
metal forming: Roper Whitney AutoBrake 2000 and Power Shear, roperwhitney.com; Millermatic welders, millerwelds.com; Lincoln welders, lincolnelectric.com
Substrates: 3M high-performance translucent vinyl, 3m.com; acrylic, aluminum
Dimensional Letters: Steel Art Co. stainless steel letters, steelartco.com
Paints + Coatings: AkzoNobel Acrylic Polyurethane and AkzoNobel Clear, akzonobel.com; Axalta acrylic enamel, axaltacs.com; Benjamin Moore IronClad, benjaminmoore.com; DeVilbiss Tekna Pro top feed spray gun and spray booth, ccisinc.com
Lighting: Bitro OpticsPROMAX and SolidFLEX LED modules, bitrogroup.com