Film-Tech Forum ARCHIVE: Dealing with broken neon tube

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Posted by Mike Blakesley (Member # 26) on 06-16-2004, 06:24 PM:

We have a broken neon tube. The sign company can't get here till next week. I've seen them put a jumper wire across the contacts for a broken tube before, but don't have any of the wire here. Is there anything special about this wire? What should I use so I can keep operating?

Any help appreciated as always.

Posted by Phil Hill (Member # 371) on 06-16-2004, 07:10 PM:

Temporarily you can use high-voltage SOLID-conductor (i.e. - NOT "noise-suppression" type) Sparkplug wire available at your local auto parts store.

Depending on what % of the total load on that particular transformer is bypassed, you may overdrive the existing "good" sections and shorten their life.

REMEMBER THE DANGER: Neon is driven by HIGH VOLTAGE. Typically between 5,000 and 15,000 volts. IF you're not sure what you're doing, DON'T F*CK WITH IT!

>>> Phil

Posted by Jon Miller (Member # 163) on 06-16-2004, 08:09 PM:

The wire used in neon signage is called "GTO wire," which consists of stranded copper wire in a heavy insulation similar to that of spark plug wire. Phil's suggestion of using solid spark plug wire is a good suggestion, if you can find the stuff. You could also ask your sign shop to see if they can FedEx you a length of GTO wire to help carry you over.

If it's a short section that's gone bad, jumpering should not have that much of a ill effect on the remaining sign, but it will save the transformer. Unlike regular transformers, so-called "luminous tube" transformers do not like open circuits and can strain to possible burnout under extended operation with an open section (the straining pretty much explains that static-y buzz associated with a failing neon sign). The transformer will not be harmed if you jumper around a broken or removed section.

Good luck! [thumbsup]

Posted by Paul G. Thompson (Member # 655) on 06-16-2004, 08:25 PM:

Phil is correct. Regular wire will fail in a very short period of time and probably create much RFI which might hack your neighbors off.

Posted by Mike Blakesley (Member # 26) on 06-16-2004, 08:39 PM:

Thanks guys -- the section that's missing is about 4 feet long. Should have put that in my original question.

Posted by Ray Kaufman (Member # 2351) on 06-17-2004, 12:55 AM:

You could simply call your repair company and ask their recommendation to jump/replace the broken section. Our marquee is made up of over 70 neon pieces. We accidentally break at least a tube every 6 to 8 months and always remove the broken pieces and cut and strip the ends of a section of wire, (left for us by our neon contractor.) After baring 6 to 8 inches from each end, we fold over the bare section in half and insert it into the hole, one at each end. We have flashers and chasers and this gets the rest of that commonly wired section back up, sans the broken piece. Calling the repair guys should get you up by tomorrow night with little effort.

Posted by Bobby Henderson (Member # 840) on 06-17-2004, 05:07 PM:

Before jumping the broken neon section you should find out just how much glass the related transformer was powering. If a lot of glass is missing the small amount left can put quite a strain on the transformer.

About the wiring, GTO cable would be good since it shielded. You definitely do NOT want to have exposed wiring hooking up neon. There is a risk of the wire grounding out to other surfaces. Our sign company has gone from using GTO cable to this stuff called Power Pro cable. It is more heavy duty than standard GTO cable and is UL approved.

Posted by Kenneth Wuepper (Member # 1174) on 06-19-2004, 06:16 AM:

Bobby,
What company manufactures the cable you are now using? I have two theatres in need of Neon repairs and your improved cable sounds like a good item at the right time.

Thanks, KEN

Posted by Bobby Henderson (Member # 840) on 06-19-2004, 12:26 PM:

The company has a website here:
http://www.neonpowerpro.com/powerflex.html

We tend to order it from various sign products supply companies. The stuff is getting popular. It makes items like neon filled aluminum channel letters easier to build and install, and it's UL approved no less. Usually when it comes to neon you have to do all kinds of expensive extra work to put up UL compliant neon signs. This is one of the few cases where the job is actually made a bit faster/easier.

Posted by Steve Kraus (Member # 476) on 06-19-2004, 04:12 PM:

Can he compensate for the missing segment with a resistor added to the jumper?

BTW, why can't a neon sign be made with vinyl or other flexible tubing? I presume it can't or someone would have done it. I suspect the pressure is very low (partial vacuum) but a very thickwall tubing ought to be able to withstand that.

Posted by Jon Miller (Member # 163) on 06-19-2004, 07:30 PM:

The tube interior has to be 100% contaminant-free, which is accomplished by "lighting up" the completed tube while under a vacuum with an adjustable high-voltage, high current transformer connected to the electrodes in a process called bombardment. The lit-up residual air generates considerable heat and bakes the tube assembly; contaminants released from the tube are drawn out. After that, neon or argon gas is introduced. Please go easy on me...it's an oversimplified explanation of the process. [Smile]

Plastic tubing would collapse or burn up under bombardment, which would make it unsuitable.

Posted by Bobby Henderson (Member # 840) on 06-20-2004, 01:36 PM:

quote: Steve Kraus
BTW, why can't a neon sign be made with vinyl or other flexible tubing? I presume it can't or someone would have done it.

Aside from bombardment, I don't think it would be possible to heat up plastic, vinyl or any other kind of PVC to the point where it is malliable without the material also becoming pourous or just melting completely apart. You have to be able to bend the glass into lots of different letters and other shapes for creating the artwork. Plastic just wouldn't do for this purpose.

Also, you have the danger that plastic emits lots of toxic gases, etc. when heated. Bending neon glass tube is already a pretty difficult process without getting things like respirators involved. To make neon, you have to enjoy working around more high voltage than it takes to kill prisoners on death row, you have to enjoy burning your fingers on a daily basis and enjoy spending lots of time making glass units (and re-making them when an installer or customer breaks it). Our neon guy curses a blue streak as it is when some unit goes FUBAR on him. I would have to videotape the tirades if he had to work with plastic tube.

Here's another alternative. If what you need are just straight sections, and you have a little more money to spend up front, you could check into some LED-based products. We sometimes use LED strip lighting from a company called Lektron. Their border lighting products can take care of jobs where there isn't enough room for neon components, or if there are too many safety issues with installing genuine neon.

Posted by William Bunch (Member # 1040) on 06-20-2004, 05:01 PM:

There is an alternative for broken neon in plastic covered channel letters. It is LED, flexible, comes in many colors (including white) and does not have all the safety issues as with neon. You buy it in large rolls and cut off what you need then attach a small power supply with ordinary wire. There is no EMI/RFI issue either.

Of course this will not solve the problem of repairing open tube neon but it is making fast inroads to the channel letter signmaking industry.

The product is called "Tetra" and you can read about it here:

http://www.gelcore.com/markets/channel_letter/index.asp

Posted by Bobby Henderson (Member # 840) on 06-20-2004, 07:37 PM:

There's a growing number of companies that make LED lighting for channel letters. The LED company we use for this purpose will take vector artwork we provide and create a drop-in panel with all the LEDs in place. We just attach it to the letter back, hook up the power and it is done. Pretty convenient.

However, IMHO, LED lighting for channel letters still comes up a bit short --particularly when it comes to certain colors. Red is okay for LED lighting. Some of the other LED colors are just not bright enough. All of the blue LED stuff I've seen really sucks ass. Also, the LED method is more expensive on up front building costs than sticking with traditional neon methods. You can gain some cost savings long term through low power consumption.

Just as an aside, I tend to discourage the use of blue in channel letter building sign design for a couple reasons. One, it takes more neon (and a lot more in the way of LEDs) to get a proper level of brilliance in a blue channel letter. Reason two: blue channel letters are much more difficult to read at night when lit. There's something about the wavelength of light that just make them blur out to hell, even when they have a proper level of light. They just have to be BIG. Unfortunately many sign companies will just build the letters with the typical amount of neon or LEDs, just to do what's "good enough." So, consequently, many blue channel letter building signs you see on the commercial landscape (including those of major companies like Honda) just don't read very well.

Finally, LED lighting tends to only work when it is not directly visible. Channel letters with Acrylic faces can use LED lighting as an alternative. But when it comes to exposed lighting LEDs suck ass. Neon is really the only way to go. There is nothing that can fully substitute the look of exposed neon glass --like this example:

Yes, there are fiber optic cable products out there. But check the prices on them as well as the light performance. Fiber optic lighting costs a LOT more and you just don't get as much brilliance as compared to neon. Fiber optic cabling has some nice color chaning capabilities, but as I mentioned you will pay high prices for it.

Posted by Jeff Taylor (Member # 443) on 06-21-2004, 08:39 AM:

Bobby's 100% right on blue neon at night. We try to stick to red and various magenta hues or white for readability at night. This is especially true in cold climates where all neon loses some output. This blue just pukes out to the point where it's gone unless you really go crazy and highlight it with a white border.

Posted by Jim Spohn (Member # 1547) on 06-21-2004, 01:21 PM:

When by-passing a section of neon tubing you need to assertain what percentage of the total neon tubing is being by-passed. For example if there are two tubes 10' long and you are by-passing one of them then you are taking 50% of the tubing out of the circuit. Neon lighting tube will take all the current you can give it, getting brighter and brighter but the tubing is also getting hotter and hotter as the current increases. The transformers are current limited to the correct amount of current for the amount of footage of tubing they supply. If you by-pass a large percentage of the tubing, you are in effect raising the current on the remaining tubing, therefore increasing the heat of the glass. The problem with increasing the glass temperature is that the wire leads on the end of the tube (that go thru the glass) expand at a lessor expansion co-effecient than does the glass, as the glass expands greater than the wire, the seal is lost and the atomsphere will leak into the tube and at first there will be flickering and then complete failure. The bottom line is that if you are going to by-pass at all do it only on a small percentage of the total tubing OR you will send the good tubing to an early grave. I would think that 25% would be a good fugure to stay under and that might even be pushing it.... enough rambling...I hope this helps... Jim

Posted by Bobby Henderson (Member # 840) on 06-21-2004, 05:17 PM:

That's true, Jim. But the more likely problem to occur when taking too much neon out of a given circuit is the penalty the ballast itself suffers. You're more likely to roast a transformer when it doesn't have a comfortable length of glass to power. And then these days the old fashion transformers are disappearing. Everything is going to ground-fault design. In a new neon installation (that is wired for UL Listing or at least National Electric Code compliance) ground fault transformers will be in use. If everything isn't hunky-dorey, the neon may just flip off the power.