You might want to ask yourself how much money you can make when your equipment is broken and non-functional.
Not much seems like a probable answer.
Far too many body shops skip scheduled maintenance on equipment. Granted, someone cleans the spray gun pretty regularly, but that person doesn’t lubricate it often. And someone will replace the booth filters when the paint work gets dirty enough – but that someone seldom cleans the dampers. And when the wire welder quits, it’s probably easier to just send it in for repair.
Your shop is too busy fixing cars to fool with this maintenance malarkey, right?
Well, folks, before we get into a list of suggested maintenance tasks that several leading vendors have suggested you perform regularly, let’s take a look at the cost of not doing it. First is the lost production when your equipment ceases to function. The national average body shop labor rate is close to $40 per hour these days. If your equipment breaks, it’s unlikely that you can get someone to fix it in less than a half day. And four hours without compressed air affects every tech in the shop. Forty dollars times four hours times four techs equals $640 down the tube on Day 1 when the air compressor quits. Even if just one tech is affected when the wire welder shorts out, $40 times four hours is 160 bucks lost.
Secondly, our industry’s $40-per-hour labor rate looks pretty cheap when you hire a specialized equipment repair person. The guy or gal who can solve your welder’s rectifier problem or the mechanical contractor who takes apart the air replacement furnace is likely to charge $60 to $100 per hour. Undoubtedly, it’s more economical to do your best to keep all the equipment in your shop working properly.
To help you do this, I located experts to share their biggest maintenance-related problems and how to prevent them. We’ll examine what’s required for the compressed-air system, the frame machine, the wire welder, the spraybooth and the spray gun. But all the good advice in the world won’t clean and lubricate your equipment. Commit to a recurring maintenance day at regular intervals to take of the equipment you already own, and you’ll save enough money next year to purchase additional equipment.
Maintaining Your: Compressed-Air System
Manufacturers of air compressors say that spending two minutes once a day in the compressor room will forestall lots of problems.
First, of course, is to simply listen for any audible leaks. The sound of hissing air signifies a problem somewhere. Next, check the pressure gauge for sufficient pressure, check the head temperature for overheating and make sure the dryers and drains are operational. A knowledgeable person will detect most problems early.
Check the oil level and condition once a week. Piston-type air compressors are bigger consumers of lubricating oil than screw-type compressors and would benefit from a low-oil warning or shut-off switch. Regardless of which type you own, in a busy shop, you should drain and change the oil every six months and at least once a year in every shop. (Keep in mind that in this and every instance in this article, the equipment manufacturer’s printed maintenance instructions are the final word on what, where and when to do maintenance.)
If the operating temperature of your compressor has increased, the most likely cause is blocked airflow. Because of all the dust we generate, compressors are easily coated with enough dust to restrict heat release. Those fins on the pump casting and those aluminum leaves on the discharge tube are simply to increase the contact surface. The more metal exposed to the air, the faster the friction heat from the pump is dissipated. If you have a refrigerated dryer or a watercooler, make sure the radiator area is free of obstruction. Once a week, blow off every “fin-looking” surface on and near the compressor. This will give you better paint work, too. Cooler operating temperatures produce dryer air. For every 20 degrees F you lower the air temperature, half the moisture condenses to water and is easily trapped out.
You also want to regularly check for leaks. Leaks mean you’re losing money. Not only will you shorten the compressor life because it runs more often, you also spend more on electricity. If no leaks are audible, check the system for small leaks by hanging around after everyone goes home. Once the system has pumped up to shutoff pressure – generally about 175 psi – and no one is using any air, wait. If the compressor kicks on again, you’ve got a leak. The most likely source is the one with moving parts, namely the quick-disconnect couplers. If you can’t feel the leaks as you run your hand around the pipe joints, use an ultrasonic leak detector. It’ll pick up the high pitch of escaping air very accurately. Failing that, good old soapy water and a brush will bubble where the leak is.
Draining the main receiver tank, the dryers and each point-of-use filter twice each day also goes a long way toward longer tool life and cleaner paint work. The main 80- or 120-gallon tank should really have an automatic drain device. Sure, sure, they’re $400 and you’re passing by the compressor anyway. You’ll just do it yourself – except for the times you don’t. The tank is also home to the most contaminated air. No place else has the water, oil, dust and rust that the main tank does, and as much as five gallons of water can reach the tank in a single shift on a hot day. If not drained throughout the day, the tank fills with water, making the compressor work harder and the air in the shop wetter, which makes the point-of-use traps work harder. One style of automatic tank drain flushes out the water whenever the water rises above the float; other styles are on a timer or electronic control. If you’ve just had a summer of water problems, consider an automatic drain to solve many of them. (By the way, automatic drains require service of their own; they stick open or shut when coated with the grunge in the tank. Rebuild them once each year.)
Regular filter service also allows the compressor to do its best work. You should regularly clean or replace the inlet filter that cleans the air on its way to being compressed. All that body filler dust plugs those babies fast. Even if your intake is outside the shop, parking lot dust chokes them, too. Choose the filter designated by the compressor manufacturer. You should also clean and replace the filters in oil separators, desiccant dryers and impact traps at frequent intervals – perhaps on the monthly or quarterly “shop maintenance day” you establish.
Maintaining Your: Frame Machine
Frame machine manufacturers passed along several good ideas to me regarding how to keep your measuring and pulling equipment operating smoothly and how to keep the operator safe.
As I’m sure you know, don’t pull with twisted chain links in the pulling or tie-down chains. You could stress the link beyond its capacity and it could fail. What you may not know is a broken chain link at 20-tons of force is moving faster than the slug from a .45 caliber handgun. Hello! Regularly inspect your chains for nicks, gouges and stretching. Replace the chain immediately if worn. And don’t heat the chain during repair because that will reduce the tensile strength.
Keep all hydraulics clean by blowing them off frequently. Keep reservoirs filled with the recommend hydraulic oil (typically 10W), and bleed all systems whenever you’ve replaced a component that would allow air into the oil passages. Use lithium grease sparingly on moving components. Replace any clamp or hold-downs if they’re cracked or stripped, and replace hardened bolts only with LKQ fasteners.
If possible, keep measuring equipment under cover or inside the case when not in use. Whether 3D jigs or electronic senders, body filler dust will affect their performance. When it seems like too much trouble to disassemble and store measuring components between repairs, think about the $10,000 to $50,000 you spent buying it. That oughta remind you why it’s worthwhile to take those few minutes to store it in a safe, clean place.
Several pulling and measuring vendors also offer a tune-up service that checks, cleans, lubricates and repairs their units. Every year or so, you might want to consider that – it’d be money well-spent.
Maintaining Your: Wire Welder
The president of a welder manufacturer gave me some sage advice. In his experience, 90 percent of MIG welding problems are gun related. So, the moment your welder begins to stutter and act up, change the tip, nozzle and liner. Chances are, you’ll be back in business. Those tiny welding contact tips – a 1-inch piece of copper – take all the electric current into the wire. And when the inside center hole is worn larger as the wire rushes through, weld quality is affected. If you can wobble the wire inside your existing tip, you need a new one.
If you touch the welding gas nozzle to the car and the current arcs around the outside of the nozzle, you’ve got a dead short. Most likely, it’s caused by overhead welding – the falling spatter has filled the air gap between the nozzle and the swan neck. Sometimes, the whole assembly has been welded together and must be replaced.
The liner is the speedometer-cable-looking part that runs from the welding torch (gun) to the wire spool inside the welder. The same horrible body filler dust that plagues every piece of shop equipment collects inside the liner and restricts the smooth wire feed. Something as simple as a terry cloth swatch clipped to the wire with a clothespin before it enters the liner will clean much of the dust off the wire. Don’t try to lubricate your way to a smooth wire feed either. Penetrating oils also clog up inside the liner and restrict wire movement. Don’t oil it! Replace the liner every six months in a busy shop, and every year in any shop. Just do it. It’s only a 10-minute job.
Teflon wire liners are designed for aluminum or other non-steel welding wire. If you run steel wire in a plastic liner, the sharp steel quickly chews up the liner and the steel residue contaminates the liner so aluminum welds won’t work well when you reload the aluminum wire. A new steel liner is generally a $20 part. Keep one on hand. In fact, a good spare parts kit for a wire welder would include a new liner, extra contact tips, extra nozzles, a tip holder (gas diffuser), a swan neck and some fuses. Most welder problems can be fixed on site with this kit. Take a moment before you call the jobber and have it hauled in for a $200 service call or pay $30 for next-day air charges. A $40 parts kit and chances are you can fix it yourself.
You also need to regularly take the side covers off the welder and blow out the ton of dust. Don’t worry about blowing loose electric or electronic connections. If they came loose with a blast of air, they were loose anyway. Once the unit is blown out, look for overheated connections, primarily on the output side. Loose cable connections cause high resistance, which equals more heat. Clues that you have a problem include terminals that may be discolored or rubber insulation that may have melted. The wire itself may be pitted from arcing or the solder-colored connections may have baked off to an overheated copper color. Most likely, all you need to do is clean and tighten the connections to restore full power. And cover the welder when it’s not in use to keep it clean and improve resale value.
Maintaining Your: Spraybooth
One spraybooth manufacturer says that the spraybooth, more than any other piece of equipment, dictates the profitability of the entire shop. If that’s true, then keeping it working right becomes even more important.
One often-neglected maintenance task in spraybooths is to promptly replace burned out light bulbs. Thing is, if you can’t see well, you can’t paint well. Since it’s quite a chore to shut down the booth and remove explosion-proof light covers or reflector shields to reach one bulb, why not replace all the bulbs in a fixture when the first one goes out? Once you’re on this routine, you’ll know they all went in together and will no doubt fail following the first bulb.
Another maintenance must: Sticky paint overspray collects on all the exhaust components. From the fan blades to the damper doors, regular cleaning and lubrication is needed for them to work properly.
Because spraybooths vibrate and vibration causes the panels to pull apart, regular caulking and panel re-alignment keep the booth producing clean paint work. Keeping the inside of the booth free of clutter also makes for both cleaner work and a safer work environment. Clean out all masking paper and plastic sheeting after every paint job, and vacuum rather than sweeping with a floor broom. It keeps the dust down.
One booth vendor estimates that 90 percent of his complaints are the result of clogged filters. Filters not only need to be replaced regularly, but must also be exactly the right type and fit precisely into their mounting holes. As the filters plug up, back pressure increases and paint work suffers. Rather than wait for rejected paint jobs, get ahead of the curve and replace booth filters more often.
The outgoing filters, called arrestors, are inexpensive and should be changed at least once a week in busy shops. It’s the intake filters that are the expensive part – which is why many shops resist replacement until long past time.
Buying the exact brand and style recommended by your booth manufacturer will ensure great performance. This is especially true for downdraft ceiling filters. These are sophisticated, expensive, air balancing filters. Replacing them with cheap filters will negatively affect any booth’s performance. Locate and secure the filters carefully within their mounting holes. Air still takes the path of least resistance and will slither around any edge not snubbed down tightly.
Balancing the airflow in a booth with air replacement is also very important. If the instructions that came with the booth aren’t clear about exactly how to vary and adjust airflow, ask for help from the manufacturer or a professional heating and air conditioning contractor. They can measure air volume (CFM) and air speed (FPM) accurately and set dampers to deliver the right mix.
Maintaining Your: Spray Gun
One spray gun manufacturer told me that they’ve discovered a new spray gun problem as a result of today’s technologies. Because today’s spray guns have more – and smaller – holes in their air caps and fluid tips and because today’s clearcoats are extremely high in solids, dried clear often restricts the proper airflow though the small holes in the air cap. (Color isn’t such a problem since you can see if the hole is plugged with red or black paint.) To the naked eye, the air passages look clean, but under a microscope, the air hole may be half obstructed with dried clear. (A 30x-power AA battery microscope is available for little money in most hobby and electronic shops.)
On some new guns returned under warranty, this manufacturer found that HS clear was collecting on the outside of the fluid tip, effectively enlarging the outside diameter. Once the air cap is installed over the fluid tip, the space between the OD of the tip and the ID of the cap (an air space called the annular ring) is partially blocked and the spray pattern is out of whack. The solution is to soak the air cap and fluid tip in special gun-cleaning solvents. But don’t use recycled lacquer thinner or even new lacquer thinner – use special gun strippers. Perhaps on a Friday afternoon, put both parts in a quart can and cover them with gun stripper for the weekend.
In these days of high-solids finishes, a normal rinse in the gun washer isn’t enough to ensure clean spray guns. Once a week, tear down the gun and spend a few minutes carefully cleaning each tiny hole. We used to tell you not to use metal wire to clean brass air caps. “Use a wooden toothpick or matchstick,” we said. Yeah right. Dry high solids and catalyzed paints are hard as a rock and need to be carefully bored out of the air holes with a steel wire. But the $80 air cap is still likely brass or aluminum and will be ruined if you carelessly gouge out each hole. Don’t twirl or twist the wire; firmly push it straight back and forth until the passage is clean. Several vendors have new gun-cleaning kits with metal tip cleaners (like gas welders use) and an assortment of tiny brushes to really clean the spray gun’s many atomization holes.
During the weekly spray gun tear down, be sure to lubricate all the moving parts with spray gun lube. The needle packing, the threads on the fan and fluid control knobs, the air cap threads and even the trigger stud all benefit from lubrication. Cycling through the gun washer several times each day washes off the lube quickly.
Speaking of gun washers, yours probably came with a plug or cap to prevent solvent from entering the air passages on the gun while it’s in the gun washer. Wonder where those went, right? If you keep the solvent out of the innards of your spray gun airways, it’ll work better. Buy some new plugs and use them.
It’s not necessary to remove the fluid tip from the gun body each time you clean the gun. Once a week is generally often enough. When reinstalling the fluid tip, remember that it must hold a vacuum and needs to be tightened down to 20 or 25 ft./lbs. of torque on some guns. This is tighter than you can get by holding the gun in one hand and the wrench in the other. A stamped gun wrench (the one that came free with your gun) isn’t a good tool for this job. Consider buying a cheap 3/8-inch ratchet and the correct 6-point socket to fit your fluid tip, and leave them on the paint bench. Clamp the gun into a vise and tighten up the fluid tip. Some newer spray guns require less torque depending on baffle design. Ask your vendor.
A word about checking the spray pattern: Spraying straight thinner through the gun doesn’t duplicate actual paint or clear very well. Try using water. It doesn’t evaporate as fast so you can still see the pattern for a minute and it more closely resembles the viscosity of thinned auto paints. Run thinner through the gun after you’re done adjusting it and before you load color or clear. Adjust the air pressure to the minimum, not the maximum, working pressure. Many painters still feel that if 30 psi is good, 60 psi is better. But you’ll likely blow out the center of your spray pattern and dramatically lower your transfer efficiency at higher pressures. Turn the horns of the air cap north-south and spray a horizontal pattern to see if you have uniform paint distribution. Change the air horns back to normal (east-west) and spray a quick moving pass to see the droplet size. If the droplets are too big to flow together, either more air pressure or better (slower) solvents will solve it.
Just Do It
Nothing you’ve read here is too difficult. And considering that you and your coworkers repair $50,000 cars with exotic metals and more electronics than the first space shuttle, it’s well worth it to take a few minutes to treat your equipment well, which will keep it working and earning longer. Schedule that regular maintenance day right now. Just do it.
Writer Mark Clark, owner of Professional PBE Systems in Waterloo, Iowa, is a well-known industry speaker and consultant. He’s been a contributing editor to BodyShop Business since 1988.