Edge-lit sign

[davekenyon]

Hi

I'm looking to make an edge-lit acrylic sign.

I've got hold of some 10mm cast acrylic and am wondering how deep to engrave on the back face?

I'd planned on using a 30 degree engraving bit and some of the lines may be a few mm wide so I'd imagine I'd need to stop the depth.

Thanks

[P.Passuello]

I use 4.5mm cast acrylic for mine and cut 2mm deep.
I'm not sure what maximum depth you would need to use with 10mm but I would have thought 2 to 3mm would be about right but it is a guess on my behalf.
Here is a video I made of the process if you are interested.
It is basically an edgelit sign with a clock in it.

http://www.youtube.com/watch?v=0Uo6C9TW0_8]Edgelit Clock.avi - YouTube

Cheers
Peter

[Pete Stenabaugh]

You will find that a 30 degree bit will cut quite deep in order to get any sort of width from a line. Unless you only want a very fine line, it may be ok, but you may find that a 90 degree bit will work best for most engraving.

Any depth at all will easily pick up the light, although the deeper you cut the more light gets attracted since there is more surface area on the side edges of the cut. If you stay with approximately 1/2 the thickness as a general max. depth you should be fine.

[davekenyon]

Thanks guys. Looks like it's time for a bit of experimentation!

[rgammage]

Hello Dave

I will add a couple of things .... in UK signs for pub food were (50 years ago) just written on Perspex sheet so any depth ... or none at all might do? Later I tried to cut perspex with a cobalt tool and assumed it would need a slow cut ..... first it cut a swirl of swarf which then melted, then a ball of melted resin appeared and then the tool burnt out! Practise on scrap to check the speed you intend to use cuts and moves on before melting, this stuff is abrasive ... or seems to be.

Regards

Richard

[aarggh]

You need to just keep a fair spindle and travel speed up when cutting or engraving perspex/plexiglass. Too slow feed and you rapidly heat up the plastic which makes a real mess of it, too fast feed and you can leave ridge marks from the cutter along the sides. I treat it just like cutting mdf, around 20k rpm spindle speed, and about 1m/min to 1.8m/min feed rate.

Perspex is an absolute treat to cut I find, once you get the speed up to what it needs at the very least, it cuts brilliantly and cleanly, and plain old HSS cutters will last forever with it!

cheers,
Ian

[HelicopterJohn]

Here are a few Edge Lit Signs I have made.

John

[bobsch]

Here are a few Edge Lit Signs I have made.

John

Very nice. Where did you get the light units?

[HelicopterJohn]

Hi Bob,

I got them here: Custom Lumenedge Edge Lighting Strips - Single Color

They will make them to custom lengths. I order mine with the extended front edge that tends to hide the individual LED Lights. You have to tell them that when you order you lights. They also have the necessary 12 volt transformers and the cords and can be ordered in specified lengths. Red, Green and Blue LEDs seem to work the best for me. I think they also offer some more expensive RGB alternating lights that would be cool. I think you can program them to do different patterns????? They are very easy to deal with.

Hope that helps.

John

[Geof]

You really don't need any depth at all, the surface just has to be roughened so the light is scattered out of the sheet not reflected internally.

[HelicopterJohn]

Hi Geof,

You are correct. Here is one that I did by cutting a vinyl stencil and weeding out the letters and lightly bead blasting the letters. Only took a few seconds to blast it. When you rub you fingers across the surface you can hardly feel any roughness.

John

[Laserart]

I have a Laser Engraver, 80 Watts, that cuts and engraves acrylic very nicely. Where can I buy the edge lighting units and are they battery or 110volt adapter powered. I use One Touch software for converting photos and the result is remarkable, I would very much like to see how they would look with the edge lighting.
Kirk