how to backlight an LED sign

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Craig F
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how to backlight an LED sign

Post by Craig F »

Hi, I am new to the group and to sign making (although not to metal work). I am wanting to plasma cut a large two sided sign (4' x 8') with a pig logo and wording for a BBQ restaurant. I would like to backlight the sign w/ LED strip lighting with different colors. I plan to make a two inch framework connecting the two sides of the sign which will allow the room for the LEDs.
I currently have the sign designed with the logo as an incomplete cutout (I have placed tabs so that the logo isn't completely cut out). I then planned to paint the logo, place acrylic behind the metal with colored vinyl on the acrylic in appropriate places to color the LED light coming through the cut kerf. My question is, will I get adequate light just through the width of the plasma cut kerf or do I need more cutout area? Or should I use standoffs and make the logo proud of the rest of the sign?
Thanks!
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Re: how to backlight an LED sign

Post by acourtjester »

The kerf will be enough, do a search here other guys have posted some really neat signs. Now if you talking a really big outdoor sign it may not be enough. Not quite the same but this was done for a church's baptismal font, with a single line of LEDs.
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Re: how to backlight an LED sign

Post by tnbndr »

In my opinion the kerf is not enough. Also not sure you need acrylic behind the logo you could use color changing LED's.
You may need to experiment a little depending on actual size of the sign and coloring needed.
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Craig F
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Re: how to backlight an LED sign

Post by Craig F »

So, I created a prototype of the sign I described in the original post and it worked well with the LED light lighting up the pig logo through the kerf cuts (open contours) that define the logo. However, my prototype sign is only 24" x 18". I am now ready to cut the large sign which will be 48" x 96"" and I am afraid that just the plasma kerf width will not be enough to allow enough light to shine through so I am wanting to widen the cuts to maybe 3/16" or so. Is there an easy way to change all of the open contours that define the logo to 3/16" wide slots in enroute?

Thanks!
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Re: how to backlight an LED sign

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Re: how to backlight an LED sign

Post by acourtjester »

it is fairly simple to make a single line into 2 joined lines to give you wider lines for light to pass through. I am using Inkscape but you can do the same with other programs. I assume the outer lines of the shield are the lines you are talking about. I did a simple demonstration to do this. In the DXF or SVG file in Inkscape select one of the single cut lines and copy it then paste it. Move it close to the original line and resize it with desired distance apart, make sure they are both paths. Using the Node tool connect both ends to the 2 lines shown, repeat with the other single. lines.
pig 1.JPG
pig 2.JPG
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Re: how to backlight an LED sign

Post by Craig F »

Thanks! I am also planning to do the same to the actual outline cuts of the pig as well. Right now the pig shows up well in the dark but I am afraid when I expand the sign by 4x that there won't be enough light to illuminate the pig. Obviously I can use the same technique for those lines. I am hoping a width of 3/16" or so will allow for adequate illumination. Thanks again for the response!
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Re: how to backlight an LED sign

Post by adbuch »

I like the way Tom did this. It's fun to edit and work with nodes. Another method would be to use the offset tool in LightBurn.
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Re: how to backlight an LED sign

Post by acourtjester »

Great David is correct and jogged my memory in that Inkscape also has a command call "linked offset" you highlight the object and chick on the linked offset under the path drop down menu and it puts a small diamond on the object. You click on the diamond and move it the distance you want to copy the original. There also is another command I just cannot remember now that works very similar too.
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Re: how to backlight an LED sign

Post by acourtjester »

Her is a little more info on the linked offset command, as shown you can move both inside and outside the original outline. Then delete the original from the group. Now to be able to move the offset a small amount you need to reduce the snaps distance as shown in the last image.
awaw1.JPG
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Re: how to backlight an LED sign

Post by Craig F »

I ended up using the offset tool in enroute. Worked great! Thanks for the ideas.
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Re: how to backlight an LED sign

Post by acourtjester »

Thanks for the feedback it shows there are several programs the can be used that future searchers will see.
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