I’d like to make the sign frame out of metal since these eggcrate displays put off a fair bit of heat. I’d like it to be lightweight yet hold 15 lbs worth of displays, but I’m not really sure if it’s best done with wood or metal, and if metal, I’m not sure what particular alloy to use nor what thickness.
What I do know:
the bottom piece will be about 28.5" * 3.5" (maybe 4")
the top piece will be about 32", same depth
the arc height is roughly 20% of the arc width (it’s roughly 275 * 1550 units), making for an angle of about 17° from arc edge to the center
What suggestions do you have for fabricating this sign? What specific material should I use, and what’s the best tool to bend it into shape?
Aluminum would probably be the best metal to use if you’re wanting to keep it light, the downside being that it’s harder to weld if you’re planning on going the full-metal route. Alternatively, if you want to avoid welding, you could CNC route a back plate out of a light wood-based material like MDF or masonite, mount the digits to that, and then use some thin aluminum flashing to go around the edges. That would be thin enough that you could bend it to shape by hand, and it wouldn’t need to be weight-bearing because the weight of the display units would be supported from behind.
If you wanted to be fancy, you could even CNC plasma-cut (or route) a curved front plate with rectangular holes for each of the dot matrix digits to stick through, then spray paint it black to match the background of the boxes. I feel like that approach would be easiest if you don’t want to make a huge project out of it and potentially have to learn new skills like welding that you might not be familiar with at this point.
Yes, 34°. We’re not gonna talk about that 6th digit Unlikely anyone will require it, so I’d rather save the trouble of wiring and logic for it, put a black space there, and stop the game at $9900 should that happen.
The displays are discrete and measure about 4 5/16" wide by 6.5" tall by 3.5" deep. Based on my crude estimation & rusty trig, the radius of the bottom circle would be 48", and 34° of that is 28.5". Six of these are about 26.5" wide in a straight line.
Thanks, and welcome to Talk. Those are very interesting ideas. I like the idea of either Masonite or the plasma cutter. In fact, I could even cut two arced pieces per side, where the outer piece would consist of holes for the tiny chasing lights along the edges, and the flashing could go between them. Although I could also simplify it by going for programmable LED strips, but then it loses some charm/authenticity.
However, I haven’t used the CNC router since before my kids were born, and I haven’t welded anything since DMS was on Ladybird Ln. I’d probably have to arrange for some help or supervision ahead of time.
Thanks for the specific suggestions on the exact alloy. I checked Lowe’s and Ace, and couldn’t find the specific alloys they sell. I might have to go to Online Metals or another specialty shop.
I like the flange idea so it makes it simpler to fabricate the corners. Especially with the Solidworks trick, it makes me think maybe I can just find one long piece of sheet metal, use the brake to bend all the corners where Solidworks says to, put the bend in it, and spot weld in one spot.
I appreciate the suggestions. At this point, I’m leaning towards the first one because then the front face is structural (rather than the bend) and I’m not having to worry about bending metal into an arc (other than thin flashing), though it means I have to make exact cuts to fit each display rather than exact bends.
Does not even need to be a flange, a couple of tabs on the rolled baffle tube around a bulb would be enough to spot weld to the base plate. The tubes should be something thin and soft like 0.010 or 0.020 6061 aluminum. You can cut them flat, roll them on a mandrel, and bend the tabs out. Probably don’t even need to fasten the seam, just overlap it a bit.
You can powder coat the whole thing flat black when you are done.
Agree with Tim and Rich. Home Depot and Ace are grossly overpriced for convenience. Metals 4u has decent prices on aluminum drops. Coremark metals and king architectural are the best places in town but they are on the outskirts
Finally had time to get back to this. I wonder where I went wrong in my math! Based on some image manipulation, it looks like the radial array is closer to 70° rather than 34°.
In any event, that’s a pretty neat trick in CAD @ESmith (is that Solidworks?). Considering there are a bunch of holes to drill for the chasing lights too, I wonder if it’s easier to just plasma cut (or CNC mill with Masonite) the front & rear plate of this shape, rather than trying to make the outside metal enclosure structural. I could probably wrap it in metal of some sort afterward just so it’s less apt to fall apart.
I see a bunch of options. It really boils down to the use case and how rigid this needs to be. That and fabrication techniques you are comfortable with.
These are incandescent bulbs, right? Heat is a consideration particularly if you are baffling most of them. Not only material that will withstand the heat. But space for cooling air to circulate.
Have you considered a modular approach where each character is a common module that links in a chain?
The plasma cutter is a useful tool, but it’s not a laser cutter for metal. There are artifacts of the cutting process- particularly around small features. You’ll still be drilling or punching a lot of holes.
The machine shop Shapeoko is allowed to use soft metal like aluminum.
I did a template for the interlock baseplates. I marked a white painted piece of aluminum on a laser. Center punched and drilled it with a 1/16” drill, and then drilled pilot holes in stacks of four baseplates. I drillled the finished holes in stacks of four. A 1/16” Hole is also small enough to reliably center a hole punch.
It’s likely some combination of these techniques will work.
The good news is these are already modular and linked in a chain – see the pic from the top. As such, what Eric drew is basically all I need. I was originally envisioning just wrapping the modules in bent sheet metal formed to the arc, but now I’m thinking about cutting what Eric made since it seems way more structural.
I wonder if the Shapeoko could be used for milling, rather than simply drilling, because at the same point in time, it’d also be nice to drill all those little chasing light holes into the perimeter of the front plate that he drew. The other benefit of that is if I wrap a front & back plate with sheet metal, there’s space for a bit of air to circulate between the modules, since they do indeed put off heat (though I’ll almost certainly be running them at a lower voltage than they did on TV).
As for comfort in tool use, it’s been years (as in, before kids) since I’ve used the woodshop CNC router (which is where I’d use Masonite), and I’ve not used any of the big metal shop tools such as the plasma cutter or Shapeoko. The upside to aluminum is maybe I could weld a strip of sheet metal to secure the front & back plates together, whereas attaching such a strip to Masonite would probably be a lot more challenging.
Unlikely anyone will require it, so I’d rather save the trouble of wiring and logic for it, put a black space there, and stop the game at $9900 should that happen.
I’d probably have to arrange for some help or supervision ahead of time.
