need help with first push through sign.

[knight_toolworks]

I bought some of those double light leds off of ebay for another us when I realized I could make a sample sign. Well I found a chuck of 1/2" acrylic in the cutoff bin at the plastic store and went to town.
the light looks even in the picture but it is far from even. I sanded the face of the letters but that only helped a little bit.
so the question is what acrylic should I get for such jobs? also to get the light even should I have the box deeper? this one was only about 1.5"
http://i154.photobucket.com/albums/s266/knighttoolworks/photo3-2.jpg

[jerry_stanek]

When you say double light leds what are you talking about? 2 strips 2 light heads leds on both sides Can you post a picture of these lights.

[knight_toolworks]

these guys. they are plenty bright but between the spacing and maybe the shallow box the light is not every even. I put 10 in and to get even light I would need to cut them and space them better. So I am wondering with a deeper box and the right plastic will it work or should I use a more dense string of lights?

[bleeth]

Steve:
Regardless of your lighting system if it is any kind of backlighting you should have a lighting reflector inside the back of the box. This is usually a bent piece of polished aluminum or stainless (Doesn't matter how thin) that goes from (in the case of your sign) from the back bottom to the front top with the lights mounted at the bottom and facing up.

[knight_toolworks]

I was wondering about that when I made another one with just a vcarved panel. the lights were too bright so I had them facing up but that still was not super even.
Now approx many leds does a sign like this about 36x9 take?

[jerry_stanek]

We found that just a white back is better that some type of reflector. On my lithos I use LED strips along 2 sides and they light up pretty even. At work we use leds for our punch through signs and we get nice even lighting with just a white back

[mims]

never tried to backlight it, but P-95 acrylic might be a good choice. . it's very 'blurry'

[joe]

Steve,

How far apart are each LED unit? It's fairly common to have a few inched distance between the back of the acrylic and the lights. Not knowing more about that we don't know every much about the problem.

J

[knight_toolworks]

they are about 2" apart. the inside of the box depth is only about 1.5"
after looking at such signs at the mall they all seem to have something on the face of the letters vinyl or paint that glows evenly. they don't seem to be bare plastic. the inside looks like this guy but the leds are directly on the back and all linked up without the extra wire.
http://i154.photobucket.com/albums/s266/knighttoolworks/photo-11.jpg

[joe]

Steve,

I haven't seen a sign this shallow. As a test, If you placed a piece of white plex where your letters will be placed, I think you would see hot spots. That's the problem.

You can place translucent vinyl on the front or back of your letters to give them a more professional look. That vinyl is known as frosted or sandblasted. Your local sign shop might sell you a couple of feet of the material.

The most important suggestion is to get rid of the wood. I know your transformed is only an out put of 12v. You'd be much better off all round with 1/2" PVC. This would help even out the hot spots.

J.

[knight_toolworks]

I thought about using sintra but these were experiments so I am glad I did not. Ok now I Know how to go about it.
one last thing how many leds should I shoot for approx?

[jerry_stanek]

First I would paint the inside white. I would mount the leds just like you have in the picture. That is what we do at work for our trade show signs. On a long narrow sign we just mount on the 2 long sides never in the middle of the back

[joe]

Jerry,

The number of light units depends, to some extent, on the depth of the cabinet and how reflective the cabinet it. A white box will distribute the light much more evenly ie Centra.

You could purchase a difussion screen to place beneath your letters. This is a common product for fluorescent lights found at your local hardware.

J.

[knight_toolworks]

Jerry,

The number of light units depends, to some extent, on the depth of the cabinet and how reflective the cabinet it. A white box will distribute the light much more evenly ie Centra.

You could purchase a difussion screen to place beneath your letters. This is a common product for fluorescent lights found at your local hardware.

J.
I had thought of the screen too. I want to get this worked out I know several of my sign company customers that can use this. Plus since my turn around time is a day or two usually that will be something no one else can provide.

[mims]

actually, I mentioned p95 earlier, but Acrylite/plexiglas Satin Ice might be better choice.

[knight_toolworks]

well I fixed the sign these pics are not the greatest.
I built a new box that is 3" deep put mirrored vinyl on the back and painted the sides white. put the leds on the ends. 6 on each end. though next time I think I will just used the mirrored stuff on back and sides since it is instant. Cost wise I can buy a 36" LED bar for the cost of these double leds so I will go that way. I only had some thick wire on hand but it worked ok. the middle is only slightly less bright then the ends less then whats in the picture. I put frosted vinyl on the back of the letters too.
http://i154.photobucket.com/albums/s266/knighttoolworks/photo5-2.jpg
http://i154.photobucket.com/albums/s266/knighttoolworks/photo1-10.jpg
http://i154.photobucket.com/albums/s266/knighttoolworks/photo2-10.jpg

[wcsg]

Your working with LEDs, so what you want to do is string your modules along the length of the back going horizontal, from the quick look you will want two rows.

You don't want to use reflectors with LEDs, you want flat white paint for the interior. This is because LEDs are pinpoint light with a limited viewing angle.

For push thrus it's best to use a rear panel or apply vinyl to the back of your letters, acrylic panel use 2337 white, vinyl use 70% diffuser film. On the fronts apply whatever translucent vinyl you desire, if your going for white letters use white trans.

It looks better on the front of the letters if you inline 1/16" of an inch from the edge. Sand your letter sides, don't flame polish.

The way you applied your LEDs will not give you an even distribution of light, thats why even from the picture you have bright ends and a very dim center.

Also, your box judging from those LED mods, use a depth of 5"


Links below you will need to register first before viewing
Here's a link for a job I did and how you would want to run your LEDs for your box, the same way neon is run
http://www.thesignsyndicate.com/forums/index.php?/topic/3255-yes-its-really-that-bright/

another example
http://www.thesignsyndicate.com/forums/index.php?/topic/1206-reverse-channel-set/

[knight_toolworks]

thanks for the tips. I found the right plastic for next time. ok no more reflective film. I will use different leds but those were what I had on hand.