5" lighted sign rule????

[TommyFastLane]

Is there a rule stating the Acrylic on a backlit sign should be at least 5" away from the bulb? Why?

 

[Mainframe]

If the face is too close to the bulb, you will see the bulb as a "hot spot" the whole length of the sign, making a wave of light pattern the whole face of the sign. I don't put flat lexan on anything less than 8 inches deep, I can see the bulbs on anything less, looks tacky to me.

 

[John Butto]

6" minimum

If the face is too close to the bulb, you will see the bulb as a "hot spot" the whole length of the sign, making a wave of light pattern the whole face of the sign. I don't put flat lexan on anything less than 8 inches deep, I can see the bulbs on anything less, looks tacky to me.

Mainframe is right in everything he said. I have used 6" but went with a softer cool white tube.

 

[Mosh]

Light banding, and DO NOT use acylic use polycarb. Plexi-glass is straight out of the 80's. If the panel is too close there are going to be dark and light spots from the lamps. This is why some cabinets us pan faces. BTW did I mention to use polycarb (lexan) if you use plexiglass I consider you a SignHACK!!!! LOL

 

[theskipman_98]

If the face is too close to the bulb, you will see the bulb as a "hot spot" the whole length of the sign, making a wave of light pattern the whole face of the sign. I don't put flat lexan on anything less than 8 inches deep, I can see the bulbs on anything less, looks tacky to me.

I also agree. We make our own cabinets and pan and emboss our own faces. We use an acrylic based face material to vacuum form our faces, so the lamps actually end up about 9-9-1/2" from the pan formed face. With this setup we use a HO white lamp. On another note we also paint all of our faces including the ones that are just panned.
We also paint the insides of the cabinet white to help distribute the light, prevent shadowing from the crossbeams and the inside assemblies of the sign; prevent rusting/better finished work

 

[andy]

As mentioned the correct distance from tube to acrylic sign face is 150mm (6"). This is the absolute minimum... any closer and you'll see nasty light "stripes".

If you run a tube in the top of your cabinet the one underneath it should be 450mm from the centre of the top tube... and so on.

Acrylic sheet allows you to use a full range of colours which illuminate perfectly... no printing, no laminating with bits of vinyl.... consistent, predictable colour results. Unlike Opaque White polycarbonate opaque White acrylic comes in many subtly different versions... all of which handle reverse illumination slightly differently.

Polycarbonate is not the "right" material for illuminated sign work... at least not in Europe. Over here we use the correct material.... Perspex, Plexiglas or equivalent PMMA brand.

 

[R08]

Light banding, and DO NOT use acylic use polycarb. Plexi-glass is straight out of the 80's. If the panel is too close there are going to be dark and light spots from the lamps. This is why some cabinets us pan faces. BTW did I mention to use polycarb (lexan) if you use plexiglass I consider you a SignHACK!!!! LOL

I hate the way Lexan yellows. I use a high impact acrylic.

 

[astro8]

Standard lightbox signs (not 'slimline') over here, which are mostly double sided are usually made from 6" aluminium extrusion, which puts the tubes only 2 1/2" away from the face. Single sided boxes have the tubes 4 1/2" -5" away from the face, depending on construction.

The faces are usually cast or extruded opal acrylic or high impact acrylic, giving excellent illumination with either translucent vinyl or double strike print.

Tubes we use these days are usually tri-phosphor daylights, spaced around 5-6"" centres.

Eg: a small 8' x 1' lightbox will usually have 4 x 4' flouros....a large 4' x 24' single sided wall mounted could have up to 48 tubes.

The boxes are almost always sprayed or powder coated white internally for reflection.

But the rule is the more space you have between face and tube the better. Large pylon mounted double sided, we like to have 12"-15" box (if possible) to give us 6" - 7" face to tube distance.

 

[Mosh]

I hate the way Lexan yellows. I use a high impact acrylic.
__________________

Put the sun-guard side out and it won't yellow.

 

[signage]

One side of Sign lexan has a UV coating to slow down the process of yellowing!

 

[Gino]

Are you guys saying the bulb from a face has to be 8" or 9" away from the face or is this the depth of a double sided can ??

I've been building cabinets for over 25 years and our double sided are fine at 10-1/2" total depth. The rule of thumb has always been a lamp should be 4" or more away from the face. The more the merrier. So if you have the lamps dead center and add 4" to each side, you're at 9 or 9-1/2" total box. Extrusions can be anywhere from 8-1/2" up to 12" and you won't have any hot spots.

To help reflect the light better, we use all white aluminum on the inside for the raceways, so then.... you don't have to paint it.

 

[astro8]

Are you guys saying the bulb from a face has to be 8" or 9" away from the face or is this the depth of a double sided can ??

Where stuck with a 6" 'can' as standard over here so tubes end up only 2 1/2" away from the face in a double sided sign.

We don't have any problems whatsoever with uneven illumination, even using tri-phosphors.

With large pylon signs i like to fab a 12" - 15" can only so as to get a 4" -6" pole up through it with a baseplate to bolt to the top of the pylon.

 

[Billct2]

Lexan yellows even when the correct side is out. I find sign grade acrylic to be whiter and brighter than lex. We use lexan when the location or size dictate it. Otherwise we use acrylic.
As for lamp distance we're pretty much doing it like Gino.

 

[surf city]

I was also taught to follow the same rule of thumb that Gino explained and that's how I have always done them.

 

[John L]

Minimum 4" from H.O. lamp to inside of face for 3/16" and thicker faces. Max 12" o.c. and start lamp spacing within 6" of inside cabinet, either side.

We have cleaned yellowed Lexan back to white with "Greased Lightening" spray cleaner available at auto parts stores by the gallon.

 

[TommyFastLane]

There has got to be $100,000 worth of information on this thread alone! Thanks Guys!

 

[Gene@mpls]

Here is the example I show people.

 

[Wes Phifer]

Bulb spacing plays a part in this also. The closer together the bulbs are the brighter the whole sign is making the banding show less. I don't think there is a hard and fast rule. There are lots of variables.

 

[Gino]

Here is the example I show people.

That looks like a 4" flush-mount can designed for a pan-face and the customer went with flat faces. :Oops:

 

[encadtech]

well - you can get away with less.. We fabbed a bunch of Verizon wireless boxes and only had 2" between the tubes and the face. The signs were double raceways 16' long - we used leds in the top cans and ho bulbs in the bottom. I had to put a metal shield in front of the bulb and relied on the reflected light in the box for illumination. This did cut down on the brightness of the bottom box - but.. it cut the light output so it actually matched the output of the leds in the upper raceway - in this application it worked well.