Some kind of plastic needed

[m_c]

This will only be getting used a few times a year, and will spend most of it's life wrapped up in a shed, so I'm not too bothered about UV stability. The ability to not fail in rain is far higher on the priority list!
It's going to be built into a box, so I'll make a cover to protect the front during transportation.

[martin54]

What are you going to use for manufacturing the box? Something like aluminium composite would probably work quite well, it's light & pretty hard wearing & you can fold it into a box shape fairly easily by routing a "V" grove to fold along. would reduce the number of joins you would have to worry about sealing.

[m_c]

Not got that far yet!

Main panel that holds everything will most likely be aluminium, which will then have the perspex mounted closely in front of it. Then all that needs a box around it. I might just go for something like ply for simplicity, then give it a good prime, and paint.
I've got somebody who could do the woodwork for me, which saves me time. If I go metal I'd have to do it myself.

[Swarfing]

Maybe the acrylic diffuser panels they use for the light units in paneled ceilings maybe a better bet?

[martin54]

Composite board has a thin aluminium skin with a plastic centre. OK it's a lot more expensive than say far eastern ply but the whole thing would be lighter & easier to move about, it's already powder coated so no need to paint & comes in about 6 different colours plus it's pretty easy to cut so your woodworking guy could still manufacture it for you. Normal woodworking tools will be ok as long as any saws are fine toothed, for small jobs I use one of those throw away laminate saws that joiners use & the V groove I do with a normal hand help router.
Not the cheapest way to do it but would look good & last for years.

[birchy]

Most of the old clock radios and such like used (brown/green) tinted acrylic to reduce the glare.

[Musht]

With Birchy, it`s a contrast rather than diffusion problem, dark tint will work better than a frost.

Amber LED might work better as well, high brightness, `sunlight visible ` are reliable and relatively cheap.

[martin54]

With Birchy, it`s a contrast rather than diffusion problem, dark tint will work better than a frost.

Amber LED might work better as well, high brightness, `sunlight visible ` are reliable and relatively cheap.

I think your right about changing the LEDs for a different colour Bruce but not sure if that is still an option.