Dual Action Sander

A must have is a DA air sander. DA stands for dual action and when referred to sanders, it means that it sands in a loop pattern as opposed to sanding patterns in one direction or a circle. The looping pattern prevents the sander from cutting too deeply into the surface being sanded. You can purchase air powered or electric DA sanders.

DA air sander

6 inch Dual Action (DA) air sander


Sanding patterns compared

An example of a circular sander is a sanding pad on a hand drill or a 4 1/2" grinder. It'll leave deep grooves in the surface being sanded. Something you don't want to do as it adds more finishing work! An interesting note is that a DA air sander uses less air than in circular sanding mode. When purchasing any air tool, check the operating pressure (PSI) and the required air flow (CFM). The better the quality tool, the less pressure and air flow that will be required.

I used the DA air sander for coarse finishing (80 grit) after the body file. It quickly cuts down the filler. There's two adjustments on the DA air sander, one is air pressure. Set it for the least amount of air to do the job. The other locks or unlock the sanding pad. You want the sanding pad to free float and to be rotate offset from the center. The key is not to press down hard while sanding but to apply light pressure. It takes some practice to find the right pressure but then it works great! The DA air sander is only good for coarse finishing as there isn't enough control to prevent waves in the sanding. A longer flat tool is required.

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Copyright Aug 2011 Eugene Blanchard