Am i missing something; Backlighting panels I'm struggling

[Rodney]

I've come up with the idea of printing a black version a couple of times onto clear see through plastic (The OHP stuff) And then a grey version on the top. That way we keep the panels grey and just line up the light areas for it to pass through between the 3 sheets. Then of course sticking it onto plexi and mounting.

Instead of the OHP stuff, there is a sticky white and clear name tag label full sheet product made by Avery. I found them at Staples. Run them trough your inkjet printer from a bitmap.

My question is though. wHat things are people using to backlight. I do have some EL wire though i don't know if that's bright enough for the job.

I don't know about EL Wire and its lumanicity, but I have used their sheets and they were bright enough. Yet, it is not the way I would do something like that again. It seems that adding LED's would be cheaper and more cost effective. Oh and the inverter for the EL Sheet throws a very high pitched sound.

[Geremy Britton]

oh i'm glad you mentioned the high pitched sound rodney. I thought it was just mine. It's horrible, and very distracting. i got to the point where i had to wrap material tightly around it to shut the thing up!

and thanks for the tip on the clear sticky paper by Avery. I'll buy some for the panels.

I also saw the lit sheets by EL , though they're very expensive even on ebay £25 for an A5 size sheet. I'm thinking that's going to be expensive to do the whole of my overhead.

Need another more cost effective solution i think ..

[Efe Cem Elci]

Not sure about pricing here yet but I'm looking into LED strips as a more convenient method of backlighting.

[stabell]

Hello!
I bought the above mentioned two-layer plastic from GravoGraph, black on the top (very thin) and white below that. The Grey version was not usable, for more than one reason. then I painted the sheets with RAL7011, and sent it to a gentleman who owns a laser engraving machine. I designed the panel myself, in a freeware vector based software called Inkscape. I saved the files in .eps, and he could import it in his laser machine.He then "burned" off my RAL colour, as well as the tiny, black layer, and reveiled the white plastic, and that is backlightable.
I am building an odd kind of sim, which is a mix between a 767 and a 737-500, so it is in the grey RAL colour.
It was not very cheap, I paid about 80 dollars for the plastic, and paid him about 350 dollars for the engraving. But he also cut out all the panel parts, about 35-40 in total.
The point is, this way you can have it exactly the way you want, and it is backlightable, and in the colour you want.
You can look at the end of this thread for pictures of the final results.

http://www.flightsim.no/ubbthreads/u...411#Post436411

[mpl330]

Not sure about pricing here yet but I'm looking into LED strips as a more convenient method of backlighting.

LED Strips are easy and quite effective but last time I bought some they did work out quite expensive.... not sure about costs now or other than UK... nice and easy to link all off 1 set of 12v/5v wires - using those and cold cathode tubes...

Cheers
Mike

[RadarBob]

Thanks for relating your experiences with Gravoply stabell - Interested to hear that the method worked for you and that the backlighting was succesful - The result looks very nice.

I had an idea that it would work, but I hadn't heard of anyone who had tried it.

I think that the top layer of Gravoply 2 is about 0.2mm thick, so the text effect is similar to engraving through a thick paint layer. You have to be vey careful with the cutter width and engraving depth when using a mechanical engraver though.

Laser engraving does not come cheap, but it sounds like you got a good deal there.

I would be interested to hear why the grey Gravoply material didn't work for you.

I have used the 1.6mm Black/White Gravoply for my CDU keys glued onto clear acrylic cubes, and the backlighting seemed ok on a test, but I haven't finished it yet - I am in the process of designing the CDU PCB (also using Inkscape), so I will have to see how well the backlighting works when everything is in place.

I suspect that the 0.8mm would have been better in terms of light transfer, but I wasn't aware that they did thinner material at the time.


Best Regards,

Rob

[stabell]

"I would be interested to hear why the grey Gravoply material didn't work for you."

The grey top layer did not block light enough. It turned out that only the black top layer would totally block it. Besides, it was not the right grey colour (well, not critical?), and the third reason was that it only came in a version that was ment to engrave from behind, or something. Or it only came in 1.6mm, I don't remember.
First I thought that I could just buy white, thin plexi, then paint it with the RAL and engrave. But the RAL colour does not block the light entirely.
So after hours ond hours, I found that the 1.2 mm sheets was the only sollution. Black on top. I also decided that I would not solder hundred white LEDs to be able to backlight it, It had to be done with the much cheaper neon lights. And that made 1.2mm the maximum thickness.

[RadarBob]

Many thanks for the info stabell.

I had not considered that the grey would let light through, but I have tried the 0.8mm sample I have here, and as you say, it certainly does.

I think I will stick with the Boeing method. at least for my Engine Start. It's not so much the soldering of the LED's I have trouble with, it's the machining of the acrylic, which takes the time - It would have been easier to use thicker acrylic
because when you drill the blind holes to accept the LED's/lamps, the depth has to be just right - Too shallow and the LED won't clear, too deep and you risk going through the panel. I had the panels cut from 5mm acrylic, but when they turned up they were slightly under. I should have gone for 6mm.

Rob

[Rodney]

Many thanks for the info stabell.
It would have been easier to use thicker acrylic
because when you drill the blind holes to accept the LED's/lamps, the depth has to be just right - Too shallow and the LED won't clear, too deep and you risk going through the panel.

Rob

Rob,
Use a drill press for this. Benefit of straight holes and the slower speed means better depth control. You can even mark the desired depth on the drill bit with tape.

[RadarBob]

Thanks for your thoughts Rodney.

I am using a drill press and setting the depth stop on a piece of scrap first, but the tolerance is pretty tight, and there are a lot of operations to get the counterbores for the illumination around the switches and the blind holes for the LEDs and surface mount resistors.

- Over 80 on the Engine Start as I remember.

Experimented with different type of drill bits (Standard twist drill/Wood bits/Forstner bits) to get the right result - But each type has its own pros and cons:

Forstner bit for example will give a reasonably flat shoulder for the counterbored holes at 22mm dia for reasonable cost, but you have to be wary that the spurs cut deeper than the main blades. Also, they don't cut that well in acrylic so you have to be dead careful of speeds and feeds otherwise they get too hot.

To get flat bottomed blind holes, I had to start with a twist drill and then follow with a milling cutter otherwise with the point angle on a normal twist drill I couldn't get enough width across the hole diameter to allow for the LED plus any error in placing it - But a milling cutter can be quite vicious, and not very forgiving !

Still, now I have found a way to do it that works for me with limited workshop facilities, the next panels should be easier. After all, I did pick one of the more complex panels to start with !

Cheers,

Rob