Construction of large illuminated prop sign

[bruce]

Not quite sure whether this comes under lighting, pr props, or FX....

 

 

I’ve been asked to think about construction of a set piece with an illuminated “show logo”. When not active, it’s just to look like a blank (probably black, but not yet decided) panel.

 

Initial ideas are an 8x4 of 4mm ply, with framing of 2x1 or thereabouts. Lettering and logo laid out on that using LED tape, then some sort of lightweight cloth over the front to hide the internal gubbins, form the blank face when it’s not illuminated, and to act as a mild diffuser for the LED, to take away the “LED harshness”, but still maintaining some punch.

 

Has anyone got any construction tips? Specifically, on a suitable material for the front covering. All ideas welcome.

 

(ps - budget is minimal - so no suggestions of video tiles etc - we’re talking LED tape, timber and paint!)

[sandall]

If you're on a tight budget, & unless you need sequencing and /or colour, how about Xmas-tree strings. Long before the days of LED I built a Tandy sequencer kit, using incandescent bulbs for a big logo & a sequence of "lift indicators".

[bruce]

The LED and electronics are not a problem - it’s the physical construction materials that I need advice on, specifically the front cover/difuser.

[Jivemaster]

remembering the days when a fine black cloth mesh was fitted to a CRT monitor to mask of axis viewing and surface reflections could this let enough light through but offer a flat black appearance when not lit?

[OllieT]

The LED and electronics are not a problem - it's the physical construction materials that I need advice on, specifically the front cover/difuser.

 

I recently did Guys and Dolls, and the set we hired included some large illuminated signs. They were quite old, so had fluorescent tubes in rather than LEDs, but they way they were designed is as follows; big wooden box made out of 2 by 4, and then a hardboard back, which the tubes were mounted to. Then on the front they had a piece of coloured Plexiglas, and then a plywood "stencil" over the top of the Plexiglas which actually formed the letters. I am not quite sure how the Plexiglas was coloured but my ideas on how they did it:

 

A layer of gel (either on the back of the Plexiglas or over the tubes), then frost to diffuse the light, then clear Plexiglas

Or maybe gel and then Plexiglas that has been sanded (Or frosted Plexiglas if such stuff exists) to act as the diffuser.

Maybe just paint the Plexiglas on the inside so the light shone through the paint

 

Pictures of these signs in use can be found here: https://drive.google...6ez?usp=sharing, sorry they aren't the best, but the photographer was focusing on the actors rather than the set for some strange reason!

Edited September 29, 2019 by OllieT

[gyro_gearloose]

Black Sharkstooth gauze over the front of your panel should give you the effect you're after.

[timsabre]

If you use gauze and don't want harshness you will need to hide the LED tape from direct view (e.g. have a ply cutout for the logo behind the gauze, then put the led tape on the back of that to light the white painted back of the backbox)

Led tape is not at all bendy in a horizontal direction so making a logo out of it is hard. You can get some continuous COB strip now which is like a bendy neon tube, that might work, but it's relatively expensive.

 

 

 

[gyro_gearloose]

For flexible led tube, Neon Flex is the phrase to search for.

[sunray]

I used this sort of stuff: https://www.ebay.co.uk/itm/UK-Neon-LED-Light-Glow-EL-Wire-String-Rope-Tube-Car-Xmas-Lights-Battery-Operated/254342217485?hash=item3b37fa3f0d:m:m3y0W9NcePuGkZMclzJPRCw

to make up a multipurpose sign, on the single board we had 'Hotel', 'Coffee Shop' & 'Home Sweet Home' in 5 different colours. In our case it was mounted on a (Rotten) black painted scaff plank suspended behind a border made of plain domestic net curtains sprayed with matt black rattle can. We had the luxury of being able to avoid illuminating the border with other lamps as I suspect the shiny tube would have shown through.

 

 

Prior to that I did a sign 'Bar' with an arrow under by drilling every 1/4" along the writing and glueing a 3mm LED in place. 'Bar' was alternate red and green to be able to make it change colour and the arrow was wired as 4 circuits to be able to make it move.The board was about 3x2ft 4mm ply painted matt black after drilling and before the LEDs fitted.

 

 

[musht]

 

Led tape is not at all bendy in a horizontal direction so making a logo out of it is hard.

 

S Shape tape is what you want in those circumstances, like

 

https://www.ebay.co.uk/itm/5M-S-Shape-LED-Strip-2835-60LEDs-m-12V-Flexible-Tape-Rope-Lamp-Non-waterproof/133182656663

 

Larger signs are usually lit with blocks , like

 

https://www.ebay.co.uk/itm/Led-COB-Injection-Module-Light-Strip-Shopfront-Sign-Backlight-DC12V-Waterproof/333324119471

 

Plexiglas and Perspex make some very nice sign plastics that appear dark opaque and then white with LED backlight, mainly seem to be Porsche dealerships using it for guide on cost. Acrylics available in rainbow of colours and finishes, so are a range of mirror, colour and frosted adhesive films.

 

Rigid subtstrates , few lighter choices over plywood, correx, foamex, top end ACM like DiBond, can router cut any of them and stretch a guaze over.

 

Back printed, back lit, stretch fabric sign?

[Owain]

The LED and electronics are not a problem - it’s the physical construction materials that I need advice on, specifically the front cover/difuser.

 

For diffuser, fresnel lenses from broken tellies? May also be a source of LED strips

 

 

 

 

[alistermorton]

I'd keep it simple, like others have said. Simple box painted white inside, tape around sides of the box and frosted cover - you could use frost gel. Rout the lettering out of wooden sheets and cover with black gauze. if you want a colou, it's easy to just fix a gel to the frost. Whether you want a perspex or other plastic sheet to support it is up to you. I've used led tape in a white box like this and you get a surprising amount if light out of it.

[J Pearce]

I can recommend the route Alister has suggested. We've made a couple this way, though haven't needed the gauze for our shows. It works best if you keep the light source out of view, so LED tape round the sides, as close to the front as possible. That way you get the diffuse bounce off the back rather than any direct light.

 

Black modelbox card works well as a front on smaller boxes (and usually has a white back too, so helps the internal reflection), saves the effort of routing into mdf.

[alistermorton]

Black modelbox card works well as a front on smaller boxes (and usually has a white back too, so helps the internal reflection), saves the effort of routing into mdf.

 

Foamboard could work well too. I think we used that for the "Recording" sign for the studio for "Glorius!"

Edited September 30, 2019 by alistermorton