A staple in the sign industry channel letters. I've made several attempts to enter this field but didn't enjoy the process. When I first came up with the idea of using LED's there was a concern about ut un-even light pattern. The first samples made were met with wild excitement from the customers. Looking back, who wants flat even lighting any way.
One of the side benefits of this sign method is ease of installation. That's because the background panel, which is nothing more than an outline of the lettering itself is the support for the whole sign. It goes up by bolting direct. Sometimes I have a two or three inch outline. The larger the outline the more reflective lighting will show. There are so many options available it's hard to imagine. For example, there could be several levels instead of two.
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The red & white sample was done using red vinyl. This left the sides of the letters, returns, their natural color.
I'm using .75" and 1" PVC. The glue is PVC Gorilla. It's nothing like regular Gorilla Glue that won't work on PVC.