Paul Bahlin
05-18-2015, 5:04 PM
I've been wanting to come up with a way to maintain high contrast in an edge lit sign when the light is off. I live in Florida so bright sun washes out plain engraving on acrylic. I also wanted a sign that could take being outdoors. Here's what I've come up with so far...
This is the sign lit and in the shade...
313810
This is the sign lit and in the sun...
313808
This is the sign not lit in the sun...
313809
The pictures don't really reproduce what's going on very well. it was 4:00 PM on cloudless day in central Florida. Lots of sun!
I do all the work on the back with mirrored graphics. First I cover with transfer paper and leave the front covered with protective paper. Then I engrave the stroke at 100% speed and 25% power. Then I weed it. Then I etch the fill with 100% speed and 80% power. This is with a 45 watt FSL laser. Clean it up with a microfiber rag and water.
When it's dry I squeeged epoxy into the pattern with the transfer paper still on. The epoxy was tinted with white opaque pigment from Castin Craft ( three drops in 1/4 tsp of resin ). Waited about 4 hours for the epoxy to get gummy so it wouldn't flow anymore, then removed the rest of the transfer paper.
Finished product will take the rain. I'm guessing the epoxy has plenty of tooth in the etched pattern so it isn't going anywhere.
My fear going into this project was that the epoxy fill would make an optical 'connection' to the etch and eliminate or reduce the scatter you need to get light out of the sign. This does not appear to be an issue at all. The light just comes up, hits the etch and does it's thing like any normal edge lit sign but now the etching is backed with color.
I did this on some other quick attempts with various acrylic paints and they look pretty good too but they aren't opaque enough to prevent light bleeding out the back and any paint thickness variation shows up in daylight as hue variation in your pattern. My best one was with a 'gold' acrylic loaded with metallics. This exaggerated the etch lines and created a really nice glittering effect when lit but when it was turned off it was kind of dull and boring.
I thought I would share because I haven't seen this backfilling mentioned here on edge lit signs. What do you think?
This is the sign lit and in the shade...
313810
This is the sign lit and in the sun...
313808
This is the sign not lit in the sun...
313809
The pictures don't really reproduce what's going on very well. it was 4:00 PM on cloudless day in central Florida. Lots of sun!
I do all the work on the back with mirrored graphics. First I cover with transfer paper and leave the front covered with protective paper. Then I engrave the stroke at 100% speed and 25% power. Then I weed it. Then I etch the fill with 100% speed and 80% power. This is with a 45 watt FSL laser. Clean it up with a microfiber rag and water.
When it's dry I squeeged epoxy into the pattern with the transfer paper still on. The epoxy was tinted with white opaque pigment from Castin Craft ( three drops in 1/4 tsp of resin ). Waited about 4 hours for the epoxy to get gummy so it wouldn't flow anymore, then removed the rest of the transfer paper.
Finished product will take the rain. I'm guessing the epoxy has plenty of tooth in the etched pattern so it isn't going anywhere.
My fear going into this project was that the epoxy fill would make an optical 'connection' to the etch and eliminate or reduce the scatter you need to get light out of the sign. This does not appear to be an issue at all. The light just comes up, hits the etch and does it's thing like any normal edge lit sign but now the etching is backed with color.
I did this on some other quick attempts with various acrylic paints and they look pretty good too but they aren't opaque enough to prevent light bleeding out the back and any paint thickness variation shows up in daylight as hue variation in your pattern. My best one was with a 'gold' acrylic loaded with metallics. This exaggerated the etch lines and created a really nice glittering effect when lit but when it was turned off it was kind of dull and boring.
I thought I would share because I haven't seen this backfilling mentioned here on edge lit signs. What do you think?