Line marking machines get heavy use. Every day they paint parking lots, roadways, playing fields, and warehouse floors. But machines wear out. Parts clog up. Lines start spraying everywhere and drive you crazy.
If your line marker machine is giving you headaches, you’re not alone. Most line marker problems are easy to predict and prevent. Here’s a troubleshooting guide to the most common problems and how to fix them.
Blocked Nozzles
We’ll start with the most popular complaint we hear from line marker customers. Why does my line marker nozzle clog up? It clogs because paint dried inside it. Paint nozzle clogs happen most often when painters skip device cleanup at the end of a job.
When you’re done spraying for the day, paint residue remains inside the nozzle. Overnight the solvent evaporates. In the morning, you’ve got a hardened paint plug stopping up the nozzle.
How to fix it:
- Soak nozzle in lacquer thinner or appropriate solvent for your paint
- Use a fine wire or nozzle cleaning needle to open the passage
Flush your device with clean solvent as soon as you finish a job. Don’t let paint sit in the machine overnight. That’s the best way to prevent clogs.
Uneven or Wavy Lines
You want straight, clean lines when you spray paint. But what if your lines come out splotchy? Or if they’re wavy? Or thin in some places and fat in others? There are several reasons you might get wonky spray lines.
Spray pressure that’s too high or too low is one of the most common reasons for uneven spray lines. If your pressure is too high, paint blasts out of the gun and your lines turn out wide. Too low and your line is thin and broken.
Paint that’s too thick or too thin will spray unevenly as well. Thick paint clogs up and won’t flow smoothly. Thin paint bleeds out of your lines and runs.
How to fix it:
- Check your pressure gauge and adjust to your machine manufacturer’s recommended setting (usually between 40 and 70 PSI on airless machines).
- Test paint thickness with a viscometer and thin or thicken as needed.
- Make sure the nozzle isn’t worn. A worn nozzle sprays an uneven fan pattern.
- Walk at the correct speed while spraying. Too fast and lines will spray thin. Too slow and you’ll blast out fat, ragged lines.
Paint Pump Not Pulling Paint
You squeeze the gun trigger, but nothing sprays out. Or it sprays for a few seconds and then just stops. Chances are your paint pump is not pulling paint out of the tank.
Cold paint can cause this. Anything below 60 to 70 degrees Fahrenheit is difficult for the pump to pull through the machine. Cold weather is the enemy of line markers. Make sure your paint is warm before loading it into the machine. Paint could also not be pulling if the inlet filter is blocked. Dirt and debris can clog up the filter just like a nozzle.
Air leaks in the suction hose cause the pump to fail to build suction as well. If the hose has a tiny hole or loose fitting, the pump tries to suck up air instead of paint.
How to fix it:
- Check the inlet filter and clean or replace if necessary.
- Inspect the suction hose for cracks or loose fittings.
- Load warm paint into the machine. It should be at least 60 to 70 degrees Fahrenheit. Warm it up with a paint heater before use if necessary.
- Prime the pump first before starting to spray, according to your machine’s instructions.
Pressure Fluctuates Up and Down
Pressure builds when you pull the trigger, but then it starts dropping off after a few seconds. When this happens, your lines become hard to control. Air trapped in hydraulic lines is often the cause of fluctuating pressures. Air bubbles disrupt hydraulic fluid flow and cause spikes and dips in pressure.
Low hydraulic fluid levels also cause pressure to drop. Without enough hydraulic fluid in the reservoir, the pump can’t build proper pressure. Weak or corroded backflow valves cause pressure fluctuations as well. Just like low hydraulic fluid, weak valves fail to hold pressure once they’re built.
How to fix it:
- First, check the hydraulic fluid level. Top off with manufacturer-approved hydraulic fluid if needed.
- Bleed the air out of your hydraulic lines. Consult your machine-specific manual for bleeding instructions.
- Inspect backflow valves and fittings for wear or corrosion. Replace as necessary.
- Tighten any loose bolts or fittings throughout the machine frame.
Paint Developing Bubbles
Paint bubbles on the surface are another extremely common painting problem. You mark a beautiful crisp line. But then, as the paint dries you notice bubbles rising up through the paint.
Heat causes this most often. Painting on hot pavement causes moisture on the ground to heat up and turn to steam. The steam rises through wet paint and forms bubbles as it escapes.
Moisture is another reason bubbling happens. Wet pavement or freshly laid concrete contain excess water. As concrete dries or rainwater evaporates, bubbles form in paint.
How to fix it:
- Never paint wet pavement. Rain or shine, make sure the ground is completely dry before you spray.
- Wait for new concrete to fully cure before marking over it.
- When spraying thermoplastic, lower temperature if paint bubbles appear.
Paint Lines Peel or Won’t Stick
You finish a job and it looks great. But after a few days or weeks, the paint starts cracking, peeling, or doesn’t seem to stick at all. Paint doesn’t adhere to dirty pavement very well. Oil spills, dust, sand, and road wax prevent new paint from sticking to the ground.
How to fix it:
- Wash the surface you’re painting beforehand. Sweep away debris. Degrease oily areas and allow them to dry.
- Use a primer coat on slick surfaces before applying paint.
- Also, make sure your paint is not expired. Old paint loses its stickiness as it ages.
Machine Overheats
Like any engine, line marker engines can get too hot. When they overheat, the machine slows down or turns off.
Overusing your machine is the most common reason it overheats. If you run your machine eight hours straight with little break, it’s going to overheat at some point.
How to fix it:
- The manufacturer suggested a duty cycle for your machine. Give it breaks on long jobs.
- Work in cooler temperatures in the morning or evening when possible.
- Change air filters regularly. Blocked air filters restrict airflow to the engine and cause overheating.
Case Study: Improving Line Marking Quality By Maintaining Line Marking Equipment
This case study explores how regularly cleaning line marking equipment can improve your paint application results.
A sports facility that frequently marked football pitches, athletics areas and training fields was experiencing mixed results. Lines started to fade on certain areas of the field within weeks, while others looked thicker and blobby when they dried.
Upon examining their line marking process they quickly ruled out paint quality as the issue. Clogging was occurring inside the spray machine, which caused inconsistent spray pressure. With improper pressure, paint was being pumped out too thick on some parts of the machine and too thin on others.
Spray tips were also partially blocked which changed the shape of the lines. Once the machine was maintained after each use the line application was much more even.
Maintenance included cleaning the machine after every use, inspecting spray tips prior to use, and properly storing the machine when not in use. Operators were also taught to spray test before starting each field marking job.
The result was even line application across the entire job, less downtime during a paint job due to maintenance, and less wasted paint from an uneven spray pattern. Lesson Learned: Take care of your line marker. You can have the best line marking device in the world, but it’s only going to work well when it’s cleaned, maintained, and operated properly.
Line Marking Machine Questions and Answers
Why does my line marker keep clogging?
There are many reasons your line marker could clog. The most common reason is dried paint from previous jobs is left inside the spray tip, hose, and/or pump system. Allowing paint to dry inside your line marker can cause extensive blockages that disrupt the spray pattern. Cleaning out your line marking machine after each use and flushing the system will prevent logs!
Why are my line markings uneven?
Lines can turn out uneven for a few different reasons. The two biggest causes are spraying too much or too little pressure and incorrect walking speed. Adjust your line marker before beginning a paint job and test the spray pattern until you achieve a consistent line.
Should I clean my line marker every time I use it?
Yes! Line marker machines should be cleaned after each use. Allowing dried paint to sit in your pump, hoses, and/or spray tip overnight will damage your machine and cause costly repairs. Cleaning your line marker takes just a few minutes, but can greatly increase the lifespan of your machine.
Why isn’t my line marker spraying paint?
If your line marker won’t spray there are several issues you should inspect before assuming it is damaged. Check to make sure your spray nozzle isn’t blocked, you have paint in the tank, your inlet filter isn’t clogged, there isn’t air in the pump system, and that you are priming the machine correctly. Also, if your paint is cold it will affect flow as the paint is thicker and will have a harder time pumping through the machine.
Why is my paint peeling after application?
Typically paint will peel if the surface was not prepared properly. Asphalt and concrete can hold onto dust, oil, moisture, and debris which will prevent paint from bonding to the surface. Always clean the pavement surface you are about to paint and make sure it’s completely dry before painting.
How do I prevent my line marker from overheating?
Line markers should not overheat when used as instructed in the operator’s manual. Following recommended use guidelines includes not running the machine for extremely long periods of time, keeping engine filters clean, and working in cooler months/parts of the day will prevent overheating. Regular servicing of your line marker will also help diagnose problems before they cause your machine to overheat.
How long should a line marker last?
Again, this depends on the make and model of your machine. But a well kept line marker that is used by professionals can last for decades! If you clean your machine after every use, replace any worn parts, and follow suggested maintenance/servicing guidelines you’ll maximize the life of your line marker.
Final Words
Prevention and routine maintenance are the solutions to most of these problems. Spending fifteen minutes cleaning your machine after each use will save you hours of troubleshooting. Your line marker will reward you with trouble-free service if you maintain it properly. Knowing how to troubleshoot common problems helps you fix them quickly and get back to work.