18 Apr 2016

Common questions and answers for achieving optimal operation and long life of SurfPrep Industrial Graded Air Sanders.


After operating an Air Tool Repair Service Center for 10 years, repairing and rebuilding thousands of sanders of various brands, I put this simple question/answer sheet together to address often asked questions to ensure many years of long life for your investment.

Think of the investment made when purchasing air sanders and the daily use and operation you plan on putting them through. As you do, now think of the vehicle you depend on and drive for daily transportation. Vehicles, like air tools, have wearable parts that require regular maintenance. Tires… purchasing new tires I’m sure is not something you look forward to. If you choose not to rotate your tires or not keep them properly inflated, plan on buying new tires on a more frequent basis. Some drivers, depending on the quality of tires, will get 65k miles of wear with simple maintenance where another driver will be lucky to get 35k miles of life. Attention to the care and maintenance of your SurfPrep Air Sanders investment will yield twice the life on your purchase, just like that of your tires. The same can be said of oil changes and the quality of oil chosen for your vehicle.

SurfPrep Air Tools have been designed and built with the highest quality materials in order to yield minimal operational costs at fractions of pennies for daily use. Wearable parts have been engineered with the tightest tolerances meaning smooth operation, long life and minimal operator fatigue.

OEM requirements:

  • All SurfPrep Sanders (12,000 RPM/3.4 CFM & 10,000 RPM/3.1 CFM) require 90 PSI.

Typical questions & answers in no particular order:

  • Why, after a period of time, does my sander slow down and lose its rate of cut even though the exhaust parts are in place, I have clean air, 90 PSI and 3.4 CFM feeding the sander?

Lack of lubrication is the main culprit. Once an operator “feels” the rate of cut slow down, place 1-2 drops of oil into the air inlet fitting.

  • When am I supposed to oil my sander and where do I put the oil?

The quick and simple answer is oil your sander when you feel the rate of cut slow down. What your sander is telling you is “I’m thirsty”! If you run flat out at 8 hours per day, 2 drops of oil at lunch and 2 drops at THE END of your day. Make sure to “throttle the sander or run it” to get the oil into the motor then put it away for the next day’s use. You want oil in the motor overnight keeping the vanes wet. Dry vanes equals less life of your investment.

  • When I activate or depress the throttle lever to run my sander, why does air just blow through and out the exhaust and my tool does not run?

(1) Lack of regular lubrication causing the 5 vanes to wear down to the point of sliding out of the slots of the rotor wedging between the cylinder wall and rotor.

(2) The incorrect oil has been used causing the vanes to “stick” in place in the rotor and not float out to catch the airflow driving the counter balance.

(3) Contaminated Air causes the Vanes to “stick” in place in the rotor.

(4) Missing exhaust parts allows sanded substrate to re-enter back through the exhaust port mixing w/ oil causing a sludge to form.

  • What happens if I do not lubricate/oil my sander?

The same thing that would happen to the engine of your car. Seize up

  • What happens if my black muffler cap/external dust filter breaks off, or I decide to remove it?

The sander will “seem to run faster” initially, but in reality every time you let off the throttle debris that is created while sanding will be drawn back into the motor assembly mixing with the oil, causing a sludge to develop slowing the sander down and eventually seizing it.

  • What if I operate my SurfPrep 3” x 4” with pressures over 90 PSI?

The design of the 3” x 4” sander, with (2) pad supports that secure the rectangular backup pad to the body of the tool, has been engineered to operate at nothing more than the suggested PSI. Sanders designed to accept a male threaded round backup pad can handle higher PSI but it’s recommended all air sanders operate at 90 PSI for optimal life and optimal sanding.

  • Why is there a mist of water spraying out of my exhaust cap?

Humidity causes water to build up in your compressor. Compressors feeding air tools, without an accessory in-line water separation filter allows water to pass through the motor, saturating exhaust filters and then exiting through the cap.

  • Why is oil dripping from my exhaust cap?

Over lubricating/oiling the sander saturates the exhaust filters and then exits the cap. You will notice excessive oil build up outside the cap.

  • When should I replace the White (12,000RPM) or Black Foam (10,000RPM) external dust filter on my sander?

With regular lubrication in the correct amount, you should never have to replace the external filter. The only time to do so would be if the filter is oversaturated with water or oil or if the cap breaks off resulting in loss of filter.

  • When I depress or activate the throttle lever to sand, while my sander is sitting on the substrate I’m sanding, why does the motor run but the backup pad does not spin?

Frozen spindle bearing. Heat created in the middle of the backup pad (especially PSA) while sanding travels up through the metal male thread into the spindle nut of the motor, heating up the bearing. Overtime, this liquefies the grease causing the grease to creep and leave the bearing. Eventually the bearing freezes up causing the pad to no longer turn.

  • What happens if I run (6) sanders in a drop station off an airline, providing enough PSI to operate all (6) sanders simultaneously at 90 PSI and then I only run (2) of the (6) sanders off the same airline with the PSI still set for (6) sanders?

The (2) sanders will now be getting more than the required 90 PSI, simply adjust your Air Flow Regulator down for the (2) and then back up to run (6). The added PSI for the (2) 3” x 4” Orbital Sanders can cause their behavior to be erratic while sanding.

  • How can I improve the ergonomics and handling of my sander?

Discontinue the use of a male plug, heavy weight coupler and heavy gauged rubber air hose. Operators who try the durable 300 PSI rated, lightweight, Red SurfPrep 12’ Full Ball Swivel Air Hose immediately experience improved handling and use of the sander.

  • I have a sander that when the throttle lever has been released, the backup pad still rotates, continuing to run until I grab it to stop the rotation, why?

Lack of lubrication causing the air flow valve and throttle post to stick, the valve is not seated properly causing air to still flow through the motor.

  • Can I use oil, other than what is recommended, in my sander?

Only if the oil is designed specifically for Air Sanders with the proper viscosity and ingredients to inhibit corrosion or contamination.

  • What is the warranty for SurfPrep Air Sanders?

One year from date of purchase against any and all manufacturer’s defects. This excludes any abuse, lack of maintenance, misuse or any operation not intended for the use of the sander.

  • Can I operate (1) sander off my 80 gallon, (2) stage, 5HP Compressor?

The answer is yes, however your compressor will kick on after approximately 3 minutes and continue to run while using the tool. Remember all Air Sanders are Air Hogs and require 3.4 CFM (lots of air)

  • The moment I connect my air supply line to my sander it immediately begins running and I haven’t even depressed or activated the throttle lever, why?

The air inlet nut was removed and during reassembly the parts were not positioned correctly, air valve/spring seated wrong allowing air to pass through into the motor at full PSI.


  • SurfPrep Random Orbital Sanders, “Round” (3”/5”/6”) with a 3/16” orbit are 12,000 RPM & aggressive, meaning a leveling tool.   A 3/32” orbit is slightly less aggressive simply due to the tighter orbit pattern.
  • SurfPrep Orbital Sanders, “Rectangular” 3” x 4” with a 3mm orbit 10,000 RPM can be set up to act Semi Aggressive w/ a “pad saver” and SurfPrep FILM, but because of design are less aggressive than either the Round 3/16” or 3/32” sanders. This sander is more of a Finishing Sander.
  • All Air tools require regular lubrication
  • Install air flow regulators with water separation filters in all sanding areas to regulate air flow and remove any compressed air condensation.
  • Air pressure above 90 PSI running through the 3” x 4” sander will result in erratic behavior that can cause a rattling noise while sanding.
  • When laying out your shop or production facility, make certain to “loop” your air supply line as opposed to “dead-heading” individual lines to different stations. Then run legs off your “loop”. A side benefit to this layout is the loop acts as an additional “storage tank”.
  • All O.E.M. parts are available from your distributor.