DA or Orbital Air Sander? Orbit, Pads, Air Supply and Swirls

Your air sander bogs down halfway across a panel, the discs keep flying off, or swirl marks show through the paint. Most of it comes down to the right motion, orbit and pad, plus enough air from the compressor.

PartsForMachines lists 127 air sanders, polishers and related tools from Chicago Pneumatic, Sealey, SIP, PCL, Draper and Sykes Pickavant for bodywork and workshop finishing.

DA, Straight-Line or Rotary: Which Air Sander Do I Need?

For most bodywork, a DA sander is the one to buy. Its pad orbits and spins freely at the same time, so it leaves a more random scratch pattern than other sanders. A 150mm model such as the 01609 6in dual-action air sander handles blending filler, smoothing and feather edging.

Other shapes have their own jobs. A long-bed or straight-line sander, with a rectangular pad, flats wide panels, and a small rotary sander tackles paint prep and rust removal where a big pad will not reach.

Why Does My Air Sander Slow Down Halfway Across a Panel?

Suspect the air supply: the compressor may not keep up with a tool that runs for minutes at a time. Its delivered air should comfortably exceed the sander’s air use, with more in hand for continuous work, so check what the compressor actually delivers (its free air delivery). Ratings vary widely between makers, so read your own sander’s figure at 90psi: the GSA04 150mm palm random orbital sander is listed at 3cfm, while the CP7225CV is rated at 7.6 l/s (about 16cfm) at load. Fit the hose bore the maker asks for, such as 10mm on a 5m hose for the CP7225CV.

Why Do Sanding Discs Keep Flying Off My Sander?

Check the backing pad first: if a fresh disc still will not stay on, try a new pad before you think about replacing the sander. Match the spindle thread and disc system. Many Sealey sanders here use 150mm hook-and-loop pads on a 5/16in UNF thread, while several Chicago Pneumatic models take stick-on (PSA) pads on 5/8-24 UNF.

The S01044 150mm random orbital air sander, for example, comes with a 150mm hook-and-loop pad on 5/16in UNF, so a spare pad for it must match that thread.

2.5mm or 5mm Orbit: Why Is My Sander Leaving Swirl Marks?

Check the orbit first. Larger orbits sand faster but leave bigger, more visible swirl marks, while a small orbit leaves marks that are hard to see. Step down to a 2.5mm orbit for the final passes before paint: the maker builds the CP7225CV, with its 2.5mm orbit, for final sanding and pre-polishing. A 5mm orbit suits general preparation, and the SA77 sits between, at 4.2mm.

To polish marks out of paint, switch to a polisher. The SA17/S 180mm air polisher is made for polishing and compounding, and runs at 2500rpm, a fraction of a sander’s 10,500rpm.

What Should I Check Before I Order an Air Sander?

• the motion: DA (random orbital) for most bodywork, a straight-line or long-bed sander for flatting, a polisher for polishing
• the pad size and fixing: 150mm or 75mm, hook-and-loop or stick-on, and the spindle thread if you already hold spare pads
• the air use at 90psi against what your compressor delivers, plus the hose bore the maker asks for
• the inlet thread: Sealey and SIP models here use 1/4in BSP, most Chicago Pneumatic models 1/4in NPT
• dust: none, a self-generated vacuum with its own bag, or an outlet for a central extractor

Browse the air sanders and polishers range, or contact the PartsForMachines team by WhatsApp, telephone or email with your compressor’s output and the job in hand.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Is a DA sander the same as a random orbital sander?

Yes. Dual action (DA) and random orbital describe the same motion: the pad orbits and spins at once. The 01609, sold as a dual-action sander, has a random orbit that combines rotation and oscillation.

Is there a small air polisher for spot repairs?

Yes. The GSA722 is a 75mm polisher with a hook-and-loop pad, running at 2500rpm. It accepts 79mm buffing and polishing heads, so it suits small areas the 180mm SA17/S is too big for.

Do I need a 150mm or a 75mm pad?

A 150mm pad covers more of a panel with each pass, so it suits flat areas. A 75mm pad, as on the GSA003, is easier to work on curved or contoured surfaces and around tight spots.

Self-generated vacuum or central extraction: what is the difference?

A self-generated vacuum pulls dust into a bag on the tool, so you need no separate extractor: the GSA06 dust-free random orbital sander works this way. Central-vacuum models, such as the GSA05 with its 26mm outlet, connect to a workshop extractor.

Which discs fit a stick-on (PSA) pad?

Self-adhesive (PSA) discs. A stick-on pad, such as the CP7225CV’s, has no hook face, so hook-and-loop discs will not hold. Check the spindle thread before you swap to a hook-and-loop pad.

My compressor is too small: is there a cordless option?

Yes. A cordless sander takes the air supply out of the picture. The CP20VOS 20V 125mm orbital palm sander has three speeds and a dust bag; it is sold body only, so the battery and charger are extra.

Can I slow an air sander down?

On many models, yes. A speed control lever or built-in air regulator, as on the GSA04 and the 06777 palm sander, lets you turn the speed down to suit the workpiece.

Do I need to oil an air sander?

It depends on the tool. Some, such as the PCL APT721, are oil-free and need no inline lubrication. For others, follow the maker’s manual for oiling and airline care.

What is a straight-line sander for?

Flatting, and getting into places a round pad cannot follow. Its rectangular pad reaches into tight corners and along door edges. The CP7264E, for example, has a 70 x 198mm pad.