As you said, your opinion, but glue blocks for studs on the back of acrylic are NOT the "industry standard". If true, big players like Gemini and Steel Art would be doing it and they don't. Default is drill/tap, flush stud on acrylic (except 1/8" & 3/16"). Unsure how "glue blocks" helps with uneven bricks, because if the bricks are in fact uneven, then there is also the risk of having the stud glue blocks (which are all the same depth) sit uneven as well depending on the wall. We keep a variety of unthreaded nylon spacers in different increment depths ranging from 1/8" to 1", easily stackable on a flush stud setup. Mixing different depths allows a variety of compensation for uneven bricks. It also allows the standoff depth to be whatever works best for the color, typestyle, etc., to ensure the shadow doesn't affect legibility (which is esp. true for condensed black letters).
Tedshock,
When I started out in signs, flat cutout letters in thicknesses greater than a quarter-inch were rare. It may be that, back then, Gemini or Spanjer Bros. offered thick acrylic letters (1/2" thick or greater), with threaded holes in the backs. But I don't remember them if they did. The standard thicknesses for flat cutout letters were 1/8", 3/16" and 1/4". 3/16" was, by far, the most common. 1/8" was used for small letters, and 1/4" was used for flat cutouts in larger sizes, say, 24-inch tall and greater. This could easily be fact-checked if anyone has any old Gemini or Spanjer catalogs from the 60s and 70s.
Nobody drilled and tapped holes in the backs of acrylic letters in the dozens of shops I worked at throughout the 70s and 80s. At least, I never saw anybody doing it.
The practice of a sign shop commonly cutting acrylic letters in thicknesses of 3/4" or greater is fairly recent because the vast majority of shops had no practical way to cut the material in those thicknesses. Router tables were rarely found in sign shops till computers came on the scene. Letters were cut out with hand tools (sabre saws, jig saws, band saws, and Cutawls) and everyone purchased threaded glue blocks or threaded glue pads from suppliers like Gemini and Spanjer. Even formed plastic letters from these companies were mounted with threaded glue blocks adhered to the backs. Tiny threaded glue blocks were available for small letters, and larger blocks were made for larger letters. When shops wanted to produce letters with a dimensional thickness, they didn't try to cut thick acrylic, they just bought the formed letters. In the decades prior to computers, I never even SAW an acrylic letter 3/4" thick. Not that they weren't produced, but they were rare. Or maybe I just wasn't paying attention (that's what my ex would say).
By the way, one method for increasing production when hand-cutting acrylic letters was to stack the plastic. Cutting two and three layers was relatively easy, as long as you used premium cast acrylic. (If you used cheap acrylic, the letters tried to melt together at the edges). And you could cut four and five layers if you were slow and careful. I watched a guy at Hardin Signs in Peoria, Ill., cut six letters at the same time. Also, a table saw can make quick work of straight outside cuts on multiple layers.
Of course, computer-driven router tables changed everything. They have allowed even small and medium shops to cut flat letters in much greater thicknesses than were ever possible before. But is drilling and tapping the backs the default method for installing acrylic letters? For letters 3/4" or 1" in thickness, it is probably the most popular method, now. But drilling and tapping is labor-intensive, and acrylic in those thicknesses is expensive. I will still often use a threaded glue block on a 3/4" thick letter to avoid the tapping operation. I won't tap 1/4" inch thick letters—not enough threads. Again, my opinion, but a stud in a hole that shallow needs more threads to keep from breaking out of the hole. And from a mechanical standpoint, for strength, drilling and tapping the backs has no advantage at all over a threaded plastic block that is properly adhered to the back of a letter. A letter will break before a good glue bond gives way.
I think you made a valid point that a letter will sit unevenly on a brick wall whether it's flush or with glue blocks standing it off. Installing a line of letters all on the same plane is more due to the expertise of the installer rather than the attachment method. Personally, I have never, or rarely, shoved letters flat against a wall, whether glue blocks were present or not. I have always visually adjusted the stand-off distance a little, by eye, rather than always relying on the glue block or a spacer. Consequently, I rarely use spacers unless requested by a customer (or a boss). And from the standpoint of visual appeal, does a slightly visible spacer look any better than a slightly visible aluminum stud? I don't think so. The bare stud is thin, whereas a spacer adds thickness, making the support
more visible, not less visible, right? So why would a spacer be better visually? I have, on rare occasions, painted studs a color close to the wall color. And obviously, using spacers to get a consistent distance from the wall is difficult on very uneven surfaces, like shake shingles or coarse aggregate, sometimes next to impossible. On corrugated metal walls, trying to cut spacers in multiple lengths can be frustrating. So why use them? And if a stud hits a bevel, what then? Spacers are not worth the trouble on corrugation. Just trust your eyes to get all the letter faces on the same plane.
Brad
geminimade.com
