Acrylic Edge Lit

[phd1658]

Hi all. I've been fooling around with both 2D and 2.5D edgelit signs with some decent results, but it occured to me that if I left the paper on both sides, not only would I protect the bottom, but also keep the front area that wasn't machined protected longer as well. Basically, I'm thinking that I could do a shallow cut on the inside of the vectors bounding the relief, then peel off the backing only where the relief will be machined. Planning on using a 60 degree fee to do it with. Any thoughts?

Thanks!

[Bob Eustace]

I always cut with it off Bill as you can see if depth is OK more easily. Have you got onto flame polishing the edges? 90 degree works fine by the way if you havent tried it yet.

[twelchPTM]

i vary my technique depending on the amount of post processing i plan to do. picking the little pieces of can be a pain in the but though... so i tend to peel the front off then handle it with kid gloves.
Bob - do you flame polish the egde where the lights are? Everything I have read and experienced indicates egde lighting works best w/o the flame...

[phd1658]

Thanks guys. Have not tried flame polishing yet. I also own an Epilog laser and read somewhere that if you laser cut the edges, it has the same effect as flame polishing.

[twelchPTM]

yes laser cutting has the same effect as flame polishing. You see a lot less "ripple" with a laser. I usually sand out the toolmarks before I bring the flame.

[phd1658]

My guess would be that laser cutting the acrylic is a two edged sword.....good for the LED edge, but bad for the other three sides. I know some folks are using reflective metallic tape on the other three, but I wonder if just spray painting the edges with some kind of reflective paint might work as well. Anybody ever tried?

[Bob Eustace]

Bill and Tom - I flame polish all 4 edges with very pleasing results straight off the saw if using pre-cut blanks. I have tried cleaning up all edges with the Rotex but its not worth the extra effort. It does take a while to get the correct speed. Mapp gas seems to give the best results..

[twelchPTM]

I use propane mostly but mapp does give you a hotter flame and the faster you can polish the less chance of burning. I remember way back when i worked in an acrylic display shop and we had a flame-polisher. If memory serves me it used M.E.K. and oxygen to produce a super small flame so hot it was clear and it polished instantly. not paying attention for a microsecond and getting to close to your hand was an instant 2nd or 3rd degree burn.

[steve_g]

When I was a shop foreman at a plastics fab shop, we used a hydrogen flame… I was told that carbon in the flame caused discoloration in the plastic. Oxy Acetylene works if you use an “oxidizing” flame, that’s one that’s hissing a bit, not the soft yellow flame! The excess O2 burns up all the carbon…
SG

[twelchPTM]

absolutly, the cleaner the flame the better. When i use propane or mapp i try to stay at the very tip of the light blue flame. I've seen guys shove the flame right up to the piece but when you see the yellow flames your not getting a clean melt and it will discolor