Come on baby light my "M"

June 10, 2006 6:08 PM

Keeping with the fine, fine tradition of querying the hive mind to build a better indie theater, I'm wondering if any mefites might be able to help me build a giant, glowing, red letter "M."

Here's what I'm thinking: first I'll build a giant aluminum case (4' x 4') and cut a big "M" out of the front panel. Next I'll glue a semi-transparent sheet of red plastic to the inside of the front panel. The final step will be hanging the monstrosity behind a huge window that's filled with old-fashioned, wavy glass (very thick, and very light diffusing). My question is this: how do I light this sucker? Should I line the box with florescent bulbs around all 4 sides? Would incandescent lights be better? How much of an issue will heat be? Where should I leave holes for proper ventilation? Should I make the back side mirrored to make the light more uniform? The red plastic will diffuse the light, as will the thick glass it sits behind, but I want to make sure that the big red "M" glows uniformly.

And if you were wondering, the "M" stands for "Metafilter"... ;)

You can see pictures of the glass here (sorry for the self-link). The third and fourth pictures show it the best.

posted by bjork24 to grab bag (17 comments total)

If it were me, I'd draw upon my home-brew PC building knowledge and light that "M" with cold cathode tubes. Heat isn't a problem, hence the name. And they're relatively easy to install and quite affordable, so you could put one or two on each side.. Power them with a low-end PC power supply bolted toward the back and you're golden.

Oh, and instead of gluing the plastic sheet (as it might tear or fall in over time), maybe you could take one the prismatic lens from a fluorescent ceiling light, cut it to size and spray-paint it red. There might even be a better way to paint a translucent surface, well, translucently.
posted by grabbingsand at 6:48 PM on June 10, 2006

And I meant to say ... with that thicker lens material, you could screw it to the aluminum with metal screws. No glue issues.
posted by grabbingsand at 6:49 PM on June 10, 2006

grabbingsand: that's a good suggestion, but I just don't think cold cathode will be nearly bright enough. I want people to really be able to see this thing.
posted by bjork24 at 7:35 PM on June 10, 2006

Have you considered simply projecting an M onto the window?
posted by TwelveTwo at 7:47 PM on June 10, 2006

You're going to need an lot of light to punch through that red film with any intensity. Here's what I'd do:
Buysome cheap Strip lights
2 @ 48" each
2 @ 24" each

The long ones are the uprights to your "M", the shorties are the internal notch of the M. Cut a sheet of plywood to match the size of the window opening. Mount the strip lights to the face of this board in an "M" pattern. Wire them up with some decent wire (at least 14 gauge solid copper).
Test the lights. Now, buy some sheets of red theatrical lighting gel. Mount these to the inside of the window with double sided tape. Then, stand the plywood up in the window frame, plug it in, and you've got a red "m". The florescent tubes will give the letter it's shape, and you'll have lots of light with very little heat buildup and lower power consumption.
posted by cosmicbandito at 8:38 PM on June 10, 2006

I still think that grabbingsand is dead on, but maybe switch for some other kind of light. It'd make almost no difference to the design he's describing.
posted by shanevsevil at 8:38 PM on June 10, 2006

With that wavy window, you won't be able to see much font details in your "M".

Why don't you make the M out of fluorescent tubes (in red colored cover sleeves) for the segments. Just mount them on a board. No need for a box.

[ the place I linked to provides polycarbonate protection covers. At other places I've seen filters just by themselves ]
posted by MonkeySaltedNuts at 8:44 PM on June 10, 2006

How 'bout masking an M off in the window and painting the rest of the glass. The existing light inside should make it glow pretty well, or add a red spotlight or two to really make it glow.
posted by davey_darling at 8:50 PM on June 10, 2006

How about something like this? -- though may be too expensive for a long-term solution.
posted by dobbs at 9:10 PM on June 10, 2006

If it stands for "metafilter", shouldn't it be blue?

If I were you, I would make the whole thing out of LEDs. Just google for "red LEDs"
posted by delmoi at 9:51 PM on June 10, 2006

How much do you want to spend on this thing?
posted by delmoi at 9:52 PM on June 10, 2006

I'm not a lighting expert, but I can't help but think a big pile of LEDs arranged densely in rows wouldn't be awesome.

They would be bright, they would never need changing, you would never have to mess around with a ballast, their directionality wouldn't be a problem (since you can arrange them densely enough).

If you buy red LEDs (f'rinstance), you'll have a greater degree of materials to choose from for the front panel, at varying degrees of opacity.

Building the LED board should be easy if you have access to a decent workshop-- buy some thin wood paneling, drill little holes for the LEDs, insert them, spread the pins outward, and run DC (from two or three garden variety PC power supplies) in strips along each bank of LEDs.

In all, I've probably set you back $120 for the lighting bit:
$ 50 in LEDs (250*$.20)
$ 60 in power supplies
$ 10 in wood

This may be more involved than the other approaches, and possibly more expensive, but I think it gives you the best profile of reliability, brightness, design flexibility (make the M any font you'd like, with no worries about shoehorning bulbs), power thriftiness, and low temperature that you're going to get.

On preview, dammit, delmoi.
posted by Kwantsar at 10:04 PM on June 10, 2006

How much do you want to spend on this thing?

Less than $300.
posted by bjork24 at 10:05 PM on June 10, 2006

and by "wouldn't be awesome," I meant "would be awesome."
posted by Kwantsar at 10:06 PM on June 10, 2006

I apologize for monopolizing your thread, but I should also mention that, should you choose to use LEDs, stripboard may be petter than the me-and-my-dad-in-the-basement wood approach, and that you'll also probably want to use a few resistors in your LED array. There are wizards to help with this.
posted by Kwantsar at 10:30 PM on June 10, 2006

Incadescents are hot. Flourescents can be a pain to get to the right shape. Noble gasses are expensive. LEDs can look techy cool or techy lame.
If you want old moviehouse charm, I'd do it with a bank of incandescents in housing with lighting gels taped in, but that may look jankity (and really big gel sheets can be costly) depending on your handiness. Luckily, the wavy glass will obviate a lot of the rougher hewing.
If you wanted it on the outside of the glass, I'd use red translucent plexiglass and flourescents with a mirrored backing.
posted by klangklangston at 11:57 PM on June 10, 2006

I think Klangklangston is right on the money. a mirrored backing with flourescents and some translucent red plexiglass or other highly translucent red glass or plastic will make that big "M" glow.
posted by planetkyoto at 12:51 AM on June 11, 2006