Here's the deal...just bit the bullet and purchased my first festool and couldn't be happier, or so I thought. I'm using the 125 to finish sand walnut and maple.  I Clean the wood and then I usually start with 100grit granat and am noticing immediately after the first pass I'm left with swirl marks.  I then sand through to about 240 (granat) and still have them.  I've read through everything here (I think) and tried all the suggestions of turning down the suction all the way, turning down the speed but just can't seem to figure out what is going on.  I was hoping somebody might have some insight as to what I'm missing or doing incorrectly. Thanks for the help guys.

I use Rubin 2 on my ETS125 because I get better results on bare wood.  And just let the weight of the sander do the job.

Andrew

If you have  brand new ETS125 you might need to break it in. Out of the box, the brushes aren't properly seated yet and need to wear a bit to get the optimal shape to fit the armature. When the brushes aren't seated yet the sander only works with reduced power. After 8 hours of use the sanders is broken in and works at full power. A method often used by people on this forum is to hang the sander by a thread and let it run freely for 8 hours.

The lack of power might be the reason of your swirl marks.    

Edit: just read you start with 100 grit. That is a relatively low grit, and will easily leave swirl marks with any sander. Start at a higher grit.

I probably just let it take the weight of my hand - not my arm.  I'm amazed at just how effective this little sander is.

I've never used it on painted surfaces, and I concluded Rubin 2 gave me better results than Granat and Cristal.

Andrew

It is a great little finishing sander and my favorite in that application. All of the above tips are good but you also need to manage the weight of the vacuum hose and power cord, if not your sander will be off balance and you will get some swirl marks.

As with all Festool sanders there is a learning curve, let the sander do the work with minimal pressure on it, making sure that it is flat to the surface (hose and cable management), controlling the suction power and using the right sandpaper with the correct grit progression. We are taking 10-20 hours of sanding before it becomes second nature to you.

Bruce

Thanks for all of the replies. Ive used the sander quite a bit so it's definitely beyond the 8hr breaking in period. I guess I'm thinking it has to do with jumping into 100 grit. What grit do you guys normally start with?  If I go too much higher I'm worried that it will be a little too fine to begin with. That could be wrong though.

Wonderwino's suggestion about the damp cloth is true, my first job was as a stainer in  a custom kitchen factory.  Average cost in 1971 was $15,000.  We actually sprayed water on all woods (oak and maple) other than pine (because of resin it  blotches.

I found offsetting the holes helps. Saw this in another post. My CT26 at full low is too much at times. Depends on wood and finish.

Also hold from the side as it removes the excess weight. Lets the tool work.

At full suction the CT will suck the sander to the surface. Probably less so with the CT-VA 20 in between as that introduces more air leakage and lower flow in general.