How many of you follow OEM recommendations for maintaining your personal vehicle? Now ask yourself why — or why not?
Many vehicle owners follow the maintenance schedule because, well, that’s what the manual says to do — end of story. Some vehicle owners perform regular maintenance because experience says if they spend a few bucks here and there, it saves them from a meltdown that costs big bucks later.
On the other hand, the reasons some people have for foregoing regular vehicle service includes that it takes too much time, it costs too much money and it’s not necessary. The excuses go on and on.
The fact is, preventative maintenance can help your vehicle last longer, work better and actually add value to it at trade-in time. Like your vehicle, your welding and plasma-cutting equipment can also benefit from a regular maintenance program.
Steps for Proper Maintenance
If you’re looking for an easy place to start, how about giving your welder or plasma cutter a bath? No, I’m not telling you to get the water hose and spray the entire machine. (Using that technique, you’ll have bigger problems than you started with.) What I’m talking about is an air bath.
A word of caution: Don’t forget to disconnect the welder from its electrical power supply! Sticking your hands or a metal blow gun inside a plugged-in welder or plasma cutter isn’t a smart thing to do.
As you give your welder an air bath, use your shop’s lock-out or tag-out procedures. Start by removing the sheet-metal sides of the machine. Then blow off the internal components with clean (oil-free), dry, compressed air. Low-pressure air is recommended.
You don’t want the blow gun to make actual contact with any of the components, so be careful. Even with the welder unplugged, you can still get a shock. Photo 1 shows a PC board that’s part of a micro-processor-controlled MIG welder. You want to be delicate about blowing off this component.
After blowing out the machine, use a flashlight to check the internal components for signs of electric arcing or overheating. Electric arcing is usually characterized by a black sooty spot. Overheating is usually characterized by melted wire insulation or discolored wire. Again, be careful to avoid touching any internal components.
If there are signs of arcing or overheating, there’s something wrong — or the potential is there for something to go wrong if you put this equipment back into service. In either case, the machine’s performance will suffer. (It’d be like expecting your own vehicle to operate at peak efficiency right after you squeeze a pair of vise-grip pliers on the fuel line.) If your welder needs repairs or the replacement of internal components, remember that such tasks are best left to qualified repair persons.
Photo 2 is a side view of a MIG welder. The sheet-metal side was removed in less than two minutes, so it’s not a big job. The cooling air is drawn in from the lower left front of the machine and moves over the main components. The series of blue things is the capacitor bank; behind it is the transformer. After passing over these components, the cooling air exits the rear of the machine via the cooling fan. Watch out: The capacitor bank has the potential to shock you.
Another useful maintenance tip is to oil the cooling-fan motor yearly per manufacturer recommendations. If you’re blowing out the machine, now is also the time to oil the cooling-fan motor because the cooling fan is important to the longevity of the welder. When the internal components get hot, the fan cools them down. If the fan doesn’t work or isn’t working efficiently, the life span of the machine may be shortened. (Some welders may have a sealed cooling-fan motor, which requires no service.)
A reminder: TIG torches, MIG guns and plasma torches are not pry bars or hammers. If you have fit-up problems or feel the need to hit something, get a hammer. Also, if you’re in the habit of moving any of this equipment around on the floor by using the torches or the gun as a handle, stop doing so immediately. Avoiding the improper use of your welding equipment will go a long way in preventing unnecessary damage.
To work efficiently, plasma cutters have specific maintenance requirements:
• Plasma cutters need an unrestricted flow of clean, dry air (at the correct pressure and volume) to the torch. If your plasma cutter has a regulator/moisture trap as part of the unit, is there a filter? When was the last time it was changed?
• It’s also critical to inspect the torch cable periodically to make sure all connections are tight and that the cable the air flows through hasn’t been crushed or damaged in a way that will partially or completely block airflow.
• Don’t forget to change the consumables in the torch when they become damaged or worn out.
Like other shop equipment, TIG welders also have specific maintenance requirements:
• If you have a water-cooled TIG torch, are you using the correct torch coolant? Some TIG welders use distilled water, while others require a special coolant. What’s the recommended schedule for changing coolant? When did you last check for leaks? Coolant leaks at the torch require immediate attention to reduce the potential for electric shock.
• Does your TIG welder have a high-frequency start? If it does, how old is your machine? How much do you use it? Are you noticing erratic performance from the high-frequency feature? When was the last time you checked the gap on the high-frequency points? Photo 3 shows what a typical gap looks like. The high-frequency output increases with a wider gap, but the operation of other nearby electronic devices may suffer. The gap is usually set with a feeler gauge. Check the operator’s manual for your specific welder, but remember that this service is best performed by a qualified repair person.
Like the other welding equipment I’ve discussed, your MIG welder is a key piece of equipment in the metal shop and requires proper maintenance to work efficiently and effectively.
For example, wire-feed speed controls the amount of welding amperage for a given electrode diameter, and thicker material requires a higher setting than thinner materials. Did you know that worn out contact tips, a partially plugged liner or any other problems with the wire-feed system can reduce the wire-feed rate?
Remember, any reduction in amperage can cause a reduction in weld penetration. Kind of scary, isn’t it? It’s entirely possible that a setting you used accurately last year is now 50 inches per minute slower because of a problem in the wire-feeding system.
Checkpoints for the wire-drive system include:
• Making sure the drive rolls are the correct type (solid wire) and size.
• Checking that the upper and lower drive rolls are in alignment.
• Making sure the guide tubes are clean.
• Cleaning or replacing the liner ASAP if the welder has been in use for more than a year. (Blowing out the liner before installing each new spool of wire is also a smart thing to do.) If you need to change the liner, follow the instructions in the manual.
• Changing the contact tip if it’s worn (egg-shaped hole instead of a round hole) or if it looks like the wire has burned back and continues to stick every time you try to weld.
• Learning how to set the correct tension on the drive rolls. There’s little sense in doing this step until you check and correct the previous items. Different manufacturers have slightly different recommendations for setting the feed-roll tension, but remember, too much drive-roll tension results in a flattened or crushed wire and a lot of bird nests.
Preventing Maintenance Mishaps
If you want your welding equipment working well, it’s essential that you perform the manufacturer’s recommended maintenance procedures as scheduled. If you don’t have the operator’s manual for your specific equipment, get one. Every welder or plasma-cutter manufacturer has slightly different recommendations for its specific equipment, so be sure to follow the correct instructions. Whatever you do, don’t attempt maintenance or repairs without the manual close by. If you create problems because you don’t know what you’re doing, you may void your warranty.
After you’ve examined the manufacturer’s recommended schedule, assign someone in the shop to perform the maintenance. Have him date and record all maintenance activity.
One final word: When you work on electrically powered equipment, safety should always come first. After all, what good is a proper maintenance program if you — or your employees — aren’t around to use the equipment?
Writer Fred Kjeld, a 20-year veteran of the collision repair industry, is an instructor at the Hawkeye Institute of Technology and a contributing editor to BodyShop Business.