That is an interesting proposal.

Hi Al,

Those were the right parameters for strings and the price is right.  I’ve chopped 3 LED groups and run them off 12 volt or popped of a single and powered it with 12 volts and a 1K resistor. It would seem that fluorescent paint would show up well.  I’d bet a go!  
 

I wonder if the rest of the roll might be used for “night operations “ too.

Nick

Don't forget

That you can make your own signs with the Miller Engineering Experimenter kit as well.  But it would be interesting to give that a try.

Fireflies not neon... but...

Hi Al,

What you are suggesting will work. I don't know the characteristics of the UV light string you linked to, but be aware that UV LEDs can easily be obtained that are very intense, and they can damage your eyes.

I used a single UV LED in this project:  Scale Model Animation 7 – Just for Fun! Smallest Scale Model Animation Ever?  https://forum.mrhmag.com/post/scale-model-animation-7-%E2%80%93-just-for-fun-smallest-scale-model-animation-ever-12194756 

You might try something I experimented with a while ago: scribe or cut a groove into clear styrene of other material,, and then fill the groove with florescent paint. I used yellow and it was nearly invisible when not lit. Then light the "window" at right angles and the "neon" inscribed sign lights up!

I found that Testors’ Fluorescent Paint was the best to use. The "glow" paints offered were terrible by comparison. Be careful using UV LEDs.

Have fun! 
Best regards,
Geoff Bunza

Edge Lit

I've wondered about engraving or scribing a clear plastic material then edge lighting.  No UV or fluorescent paint.  I think oscilloscope reticles are done this way.

Thanks

Thanks for the replies...

Years ago, Miniatronics used to make edge-lit "neon" signs (maybe they still do?  Haven't checked their website).  I tried one - this was maybe 20 or 25 years ago - and, while it did work, it used one of their incandescent mini bulbs, and the "sign" was not very bright.  Maybe that idea would be better with LED's.

I'll have to research the intensity thing, as I certainly don't want to damage my eyes!

Thanks again,

Al Carter, Mount Vernon, WA

Signs

Good Afternoon Al

There are a couple attempts using neon acrylic paint.   Both signs use 3 volt UV LEDs that have been molded into the roof. Everything is 3D printed.   The hotel sign uses 7, the Palace 4.

The Palace sign is basically recessed and I painted the recess.  The Hotel sign is script characters that I painted.

I have not tried other types of paint because the stores are just now opening. But I think I’ll try the Fluorescent paint Geoff suggested.

Hope this helps

John

3D Printer + Clear resin + Raised Letters + LED = NEON

Happy Independence Day to All,

I designed and printed clear signs using raised letters and borders on my 3D printer.  The signs included 3mm mounting tubes on the back.  I painted the signs white to reflect the light, painted a dark color over the white and then scraped the paint off the letters, borders and ends of the mounting tubes using a hobby knife.

I glued the sign to the building, passing the mounting tubes through holes in the wall and painted the interior wall black to prevent light leakage.  3mm LEDs were glued to the end of the mounting tubes and heat shrink tubing was used to enclose the LED and tube and prevent light leakage inside the building.

The white paint helps the clear resin reflect and transmit the light through the tubes and illuminate the borders and letters of the sign.  It requires a bit of fiddling around...but gives a great effect.

@John

Hi, John,

Thanks for providing your method for neon signs - they look great!  I don't have 3D printing capability, but do have a "collection" of raised letters that I thought I could use, on a (probably) black background, thinking I could use the UV black lights (LEDs) as you did.

May I ask...  Do you remember the brand, or source of your LEDs?

Also, assuming this is HO scale, what brand is  the theater structure?  Or maybe you scratchbuilt it?

Thanks for your input!

Al Carter, Mount Vernon, WA

@Bruce

Hi, Bruce,

Thanks for your reply.  Your technique sounds pretty cool, and do-able, even with a bit of fiddling, as you say.

If possible, could I beg you for a photo or two, just to help clarify this technique in my mind?

Thanks,

Al Carter, Mount Vernon, WA

@Al

Good afternoon Al and thank you

The LEDs are 3 volt, 3mm UV LEDs I found on Amazon.  Nothing special.   A couple alkaline batteries can light.

https://www.amazon.com/CHANZON-Transparent-Lighting-Electronics-Components/dp/B01AUI4W28/ref=sr_1_5?dchild=1&keywords=chanzon%2B100%2Bpcs%2B3mm%2Bled&qid=1593896087&sr=8-5&th=1

My model is HO scale and everything except the people are my design and 3D printed.    For reference attached are designs for the signs.   The LEDs are in the 1/8 in tube.

John

Neon Glass Tubing

The examples being shown may make some nice looking signs, but don't resemble what I think of when speaking of neon signage.  I think more of glass tubing (in the 3/8" - 1/2" dia. range) with gas in it.  The glass tubing is formed into letters and "striping".  Is this what these ideas are supposed to be simulating?

To my eye, most of these examples look more like modern back-lit signs.

@John

John,

Thanks for the further explanation and drawings.  Seems do-able, even for me < grin> .  I imagine I could just put plain white LEDs into tubes to act as spotlights, on a sign (not neon).  

I don't suppose you offer these fixtures commercially, do you?

Al Carter, Mount Vernon, WA

@Jack

Jack,

Yes, you are right, you aptly described true neon signs, but the only way to approximate that look is to laser cut (etch?) into clear acrylic and then light from the side, as was described earlier.  I don't have that capability and was just looking for another method to make a neon-appearing sign...

Al Carter, Mount Vernon, WA

An Early Experiment

Many years ago (the early '70s) I did some experiments with creating neon lighting.  I used brass wire bent into letter shapes (similar to what I had seen on real fixtures), and also some strips to use for edging around a sign, and some building cornice.  Using "fluorescent" paints, a pinkish red and a green, I painted the wire shapes, then mounted them on the building front and sign.  In normal lighting, they just looked like painted wire.  Using a fluorescent black light tube "BL", there was a faint "glow" to the "neon" lights.  The BL type lamp gives off both UV light as well as more typical fluorescent light.  It looked like a brightly lit moonlight scene, but the neon effect wasn't nearly strong enough.

Next I tried using a fluorescent tube "BLB" which is the one that emits little visible light, and it made the "neon" much brighter . . . but it still looked like glowing paint.  And the visible light emitted by the tube just made the scene look purple.  It also made the white features on buildings (even white painted siding) "glow".  In other words, it just looked like typical black light effects we have all seen with "glowing" signs, or perhaps skeletons and monsters in the haunted house at an amusement park.

The bottom line was I just wasn't impressed enough with the result to continue with the project.

I wonder what effects one could achieve now though with LEDs and other newer techniques?

I was going to go that route

I was going to go that route but went with UV 5mm LEDs and arduino  instead.  I have white led strips like that and also blue for night time running.

Old Magazine Article

Model Railroader August 1992 had an article on this. It's reprinted in one of Kalmbach's structure detailing books, too.