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The Process

The first step toward making repairs easier and more profitable is to make a pattern from the remaining tube. Why make a pattern first? Because often the original pattern or design is unavailable and if you break the only remaining section of a sign, you will wish that you had made a pattern. Now to make the pattern, simply trace the tube onto bending material or pattern paper. Draw tight around the tube to best represent the original. Then fill in the blanks, the broken or missing parts, as best you can. A photo of the original or a tracing of background paint or vinyl can help a lot to fill in those gaps. Otherwise, your best guess based on the letter or artistic style will have to do.

Once you’ve got a pattern, scrape off old insulators and block out paint. This step has two purposes. It helps you to determine if the unit is a mercury tube or neon tube and helps reduce unwanted smoke in the shop during tube heating and processing. Of course, it is important to fill the tube with the original gas to produce the same color tube. But a mercury tube demands special consideration. If you spot mercury in the tube or on the electrodes, you must decide whether the repair is worth the risk. Heated mercury produces vapor that is extremely hazardous to your health and in some cases may even be an insurance liability. These days, it is best to recoup and store dirty mercury then remake the entire tube to avoid both risk and potential liability. Included in this step is wiping the tube clean. This is to help keep unwanted particles from entering the tube during the repair.

The third step could also be swapped with the second. It is to check the tube for vacuum, unless of course the break is obvious or the tube is uncoated. You run the risk of damaging tube coating if you skip this test. So, use a tube tester or spark coil to determine if the tube is evacuated. If the tube lights during the test, it remains under vacuum and cutting the tube will cause air to rush in. This rush of air sometimes blows the powder coating from the glass wall then requiring that you remake the entire tube.

To ease air into an evacuated tube, heat with a hand torch the sealed tubulation tip. Usually, it will crack and upon cooling, you can squeeze it tight between your fingers and ease air into the tube. Well-annealed, stubborn tubulation may not crack. In this case, consider heating the pinch seal at the electrode wires. Once the cracked seal cools, gently break it apart. If neither of these methods works, heat either seal with a hand torch then apply an ice cube to add strain ­ and you thought ice cubes were just for burns. But make sure you wear eye protection in case the glass shatters.

So, you’ve decided to make this repair. Now, what? Well, know this: old coated tubing when joined with fresh coated tubing sometimes lights a different shade. This is because phosphor potency diminishes over time. If the tube is very old, suggest to the customer remaking it. And if the repair is part of a bigger whole, inform the customer that it may light differently; it’s the fair thing to do. The same is true of some uncoated Classic glass tubes; color matching may be difficult. Also, use the same tube diameter or risk dissimilar light output. Small diameter tubes light more brightly than large ones. So mismatching tube diameters affects the repair’s relative brightness.

Well, we are finally down to the craft called glassblowing. To start, tap the tube then gently blow out loose phosphor coating and other unwanted particles. Some go so far as rinsing the tube with water. Fine. But when left in a tube, loose powder looks like dirt when lit and is quite unsightly. Now, consider that making a glass repair usually means, you’re working with someone else’s glasswork and sometimes that work is better than your work and sometimes it’s not. When it’s not, be wary of strain imbedded within the glass tube. You can’t see it but its there waiting to strike like a raging viper.

When a long slow curve cracks from strain, jump ahead of it and heat a small ring of tubing. Once molten, draw the glass in very slightly then let it cool completely. If the crack proceeds along the curve, it will stop at this point. Here you can safely cut the tube then finish the repair. Once-in-a-while, you run into a unit that contains so many glass strains you wonder why the tube didn’t explode long ago. Rather than fight continual cracks, chips and breaks call the customer and explain that a complete remake is in order. Otherwise, you run the risk of a two-hour repair turning into an all day event.

Don’t forget the electrodes

Electrode replacement is paramount during repair work. Yet you would be surprised how many don’t do it. Using old electrodes sets up both the tube and you for untimely failure. Don’t do it to save a couple of bucks. Simply chop off and properly dispose of the old electrodes and weld on a fresh pair. And use oversized electrodes rather than undersized. Simply reduce the diameter of the electrode as shown in the illustration below. It’s inexpensive insurance that the tube will process in good order, then last nearly a lifetime.

All right, the repair is complete and the tube is ready for pumping. A question often arises, flushing. Is it best to flush a tube during processing or not? I consider the answer a respective one. If you have better results flushing your repairs with flushing gas then by all means do so. If it never crossed your mind to do such a thing and you’ve had no problems, then why start? There are so many variables each time a tube is made or repaired, that I won’t even pretend to guess which answer will work best for you. You can experiment to your hearts content if you like. But once the tube is pumped and burned-in, remember to wipe off pencil marks then block out tube sections never meant to be seen lit. I don’t know how this step is forgotten but it sometimes is and provides a glowing example of why a customer should shop elsewhere for their next neon sign or tube repair.

Finally, complete repairs to neon should also include the inspection of associated components like insulators and wiring, transformer and tube supports and electrode housings, chains, nuts and bolts, etc. Inspect every sign item for rust, electrical arcing, even blocked air vents and plugged water drain holes where applicable. This last step helps assure your work is a profitable, awarding and lasting repair.