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Are they like little half moons? I get those too. I didn't realize it was the sander until the last guitar. They'll sand out with higher grits by hand. Leveling is the hard work anyway.

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Sorry Filippo, I thought you were leveling finish. I haven't experienced that on bare wood.

I do not know if this is at all related, but a rep for Festool told me that too high a vacuum for dust collection sucks the machine against the wood and can cause problems.

I would agree with this and when using my ES-125 I have to turn the suction down on my CT-22 to about half. If I don't the excessive suction bogs the ROS down noticeably. This is not unlike pressing the ROS very hard too which will also bog it down but not until I am nearly standing on it in terms of pressure.

Also - prior to finishing I never sand beyond 220 and I do use the Festool ROS for my final sanding. IMHO I want some mechanical adhesion of the early finishing coats and sanding to 220 only helps this along.

Doing as I do above I have never seen a swirl mark from my Festool ROS.

Agreed. I learned finishing from Peter Gedrys, the finishing expert on Fine Woodworking's site. He used to also teach at the woodworking school. The one thing he pounded into my head is that people in general over-sand the bare wood prior to finishing. 220 is all you need. I actually sand with 150 or 180,, then wipe down with a very slightly damp cloth to raise the grain prior to the 220. Then the finish goes on.

The FINISH gets leveled and sanded at the higher grits to get the glass smooth gloss we all strive for.

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Mitch

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220 is all you need. I actually sand with 150 or 180,, then wipe down with a very slightly damp cloth to raise the grain prior to the 220. Then the finish goes on.

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Yes, I used to sand down to 320 but found it's not necessary pre-finish.

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Anderson Guitars
Clearwater,Fl. 33755

220 grit is adequate for most wood that will receive a finish. But I have found that going to 320 sometimes helps on plastic, ebony, and figured maple. These two wood species seem to pop with the finer grit paper. Plastics will sometimes show 220 grit sanding scratches under a finish.

If you're going to wipe on any stain, 220 grit will show too. Don't get me wrong, I'd love to stop at 180, but for wiped stains we go higher.

To get back to the original topic, is too much vacuum the problem? I have the same festool sander as Hesh and I have quit using it because it leaves such bad swirl marks. It seems to grab and throw itself to the side as I'm using it and leaves major scratches. I was really excited to get it and now it just collects dust on a shelf. I was using it with a 6HP ridgid vac and dust deputy. The dust collection is outstanding but otherwise it is a big disappointment.

Paul

Filippo, if it helps, Festool recommended putting the vacuum around 1/3 power when sanding when I emailed them a little over a year ago. Full on when using the Platin pads, 1/3 when using paper.

There is also a speed adjustment. Maybe you could try dialing down.