Dual action sanders: Tips for maximizing performance & finish Washington DC

Sanding Tips

1. Start on the workpiece.

   This will eliminate the sander from the surface.

2. Stop off.

   This eliminates the possibility of the sander walking across the surface causing wild scratches and allows the operator to have total control of the sander.

3. Do not sand at an angle to the workpiece.

   It will cause gouges that are difficult to remove.

4. Always keep the sander flat on the workpiece surface.

   This will eliminate producing an irregular surface finish.

5. Avoid using excessive pressure.

   Let the sander do the work; apply light to moderate pressure for consistent finish and removal rates.

6. Use an overlapping sanding motion with the grain of the wood when possible.

   Sanding in only one area will change the finish of the wood and result in a change of appearance once the wood is finished. Sand the entire surface evenly to prevent blotching or spotting.

7. Use the correct grit size for the operation/process to obtain optimum performance and finish.

   Choose the proper grit:

   • 80 grit — rough removal of wood, plastic, paint, filler, putty
   • 100-150 grit — breaking edges and general cleanup or major repair
   • 150-220 grit — final inspection, touch-up and minor repairs
   • 180-320 grit — washcoat and sealer sanding

   DA sanders create a finish that is approximately one to two grits finer than a sanding belt finish. Example: 220-grit belt = 150- or 180-grit disc.

8. Maintaining the sander is paramount.

   It should be oiled a minimum of once per shift one to three drops of oil directly into the air inlet on the sander. The oiling process should be conducted in a designated area so when the oil is exhausted, it will not contaminate the workstation or workpiece.

   Clean or replace exhaust muffler elements as needed; "Never Remove Or Operate Tool Without One."

9. Use the proper air hose.

   Never use a coiled hose if possible; it restricts the air more than a straight hose and, more often than not, is longer than required.

   Hose length should be as short as possible and should never exceed 20 ft. in length. For every additional 20 ft. of hose length, the air pressure drops by approximately 50 percent.

10. Use couplers and plugs.

    Maximum flow couplers and plugs should always be used; they are 35 percent larger in diameter than standard ones and allow optimum airflow to the tool.

Effects of a back-up pad on finish

Back-up pads are usually overlooked in most sanding operations. The reason for this is there is a misconception that as long as the disc adheres to it, there is nothing wrong with it. This is completely incorrect. A back-up pad has a direct relationship to the finish being produced, removal rate and abrasive life, it is a tool. There are three commonly used back-up pads: low profile, low profile tapered and tapered — each one available for either PSA or speed-grip discs. When the out periphery of the back-up pad is damaged (i.e., separates from the foam, foam is torn or adhesive remains on the vinyl face), it should be replaced immediately. All of these issues can and will cause surface defects because the abrasive disc is unable to sand flat and evenly on the workpiece surface.

What can cause swirl marks?

• Inadequate airflow
• Damaged back-up pad
• Back-up pad that is either too soft or too hard for application and grit size
• Incorrect operator technique
• Sanding too fast in an overlapping motion
• Wrong type of sandpaper and/or grit size for application
• Poorly maintained DA sander