Was your vacuum on full suction? Turn the suction all the way down and try that.

It’s feisty sander that one. Not as mannered as the 150 at all. Took me a little while to learn hire to handle it when I first got it, just takes a little more consideration, and can’t be whisked around the surface in any and all directions like most sanders.

I promise that practice takes care of the issues, but I’ve had two for 5 years or more and as much as I LOVE their performance and versatility, they are a bit of a handful compared to most other sanders, like I said the ro150 is way smoother in use.

Try placing your one hand atop the sander and the other on the cord where the plug connects to the sander.  This will allow better balance and should eliminate the skipping.

@Dove_Tail, were you ever in the military?  If so, do you remember those 18-24" floor buffers we used to use to buff the barracks floors?  Remember how we used to have to learn how to balance the buffer on the brush so that the buffer wouldn't throw us across the room and sit there laughing at us as we picked ourselves up off the deck?  Once we got the hang of balancing the buffer, we could maneuver them easily with one hand as we did the barracks detailing.  The same principle applies to the RO 125.  You have to find the balance point, then "let the tool do the work" (quoted from His Sedgeliness).  Hand placement is also critical, as noted by Pompeio.  Hold the sander by the power and suction connectors to lengthen the lever in relation to the fulcrum, and put very little pressure on the RO 125 head.  Again, "let the tool do the work".  Also, take a good look at Larry Smith's video on YouTube -
. 

He's using the RO 150, but the data applies to the RO 125. 

Guys,

Thanks so much for your helpful input.  I am encouraged to stick with this sander.

Can anyone talk about:
1) What grits you go through in Rotex for rough smoothing and
2) Then what grit you start with your finish sander?

I use an ETS EC 125 for finish sanding.  When I don't have this smoothing to do, I normally go 80 or 120 down to 220, then apply Arm-R-Seal.

Cheers,

Mark

A few years ago, not long after acquiring my Rotex I attended a Festool roadshow in Houston. When I complained to what was clearly a very knowledgeable woman she helped me with some very useful tips. The first part of the tip was what Pompeo and Shane said. The second part was to put your right arm under the vacuum hose before you grab the back of the sander. This causes the hose to wrap around your arm and really helps maintain the flatness of the sander on the workpiece. It gives you much better leverage to keep the sander in the right position on the workpiece. It works, try it.

A couple of more thoughts on this. If you follow Pompeii and Shane’s advice be careful about that left hand on top of the sander. Do not apply pressure, just a light touch to steer, downward pressure is really not needed. One of the hardest things for me to get used to about Festool sanders, especially the Rotex, is to let it do the work, light touch, be patient.

The next thing is break in. I know that someone brought this up. I don’t have a strong opinion about breaking in a sander and exactly what that would like like but I do know this. Use it, use it a lot, somehow this jumpiest you describe does get better with use.

Watch every video you can about proper Rotex use. Sometimes just picking up that one little thing can change your approach enough for you to feel your way to a better place. Once that happens you will be on your way.

Also, inspect the pad that you are using. In rare cases they can warp and that will exacerbate any problem that you are having.

To follow up on Alan's comment...I'm not sure which is being broken in, the sander or the user, but I will absolutely confirm that the more you use a Rotex 125 the easier it gets and the more you'll like it. If it weren't for the weight, I would say it is the only sander I need at all. Given its weight, I might add a palm sander to the arsenal some day, but the Rotex 125 has shelved my Bosch random orbit

I'm in the same boat as the original poster.  I'm really bummed by the performance of the rotex 125 and am afraid I may have just flushed a lot of money down the toilet.  I loved my friend's rotex 150, but this thing is comparably a nightmare to use.  I've sent it into Festool twice now and am assured it is working as intended.  I guess my question is, is it worth it?  Like if I do eventually figure out some way to use this thing without it jumping and skipping around the work surface, dramatically trying to keep me out of some areas and pulling me into others, is it something I'll be able to use on smaller workpieces?  Is it so powerful that you need to fully secure anything you take it to?  With my old dewalt 5" orbital I can just set a piece on some bench cookies or on some shelf liner and it works great.  Would this sander, if I did master it, be able to work in that way or would it just throw stuff around without being fully secured?  I was really excited that this sander would be able to handle fine work as well as rougher stuff with the excellent dust collection and get rid of the whirls.  But with my experience so far I can't even use the thing on anything but scrap because of how much it scuffs things up.

It definitely CAN do the job - once YOU learn how to handle it.  This is not a slam at you personally.  It is a recognition of the fact that there are definitely techniques to be used that can help you use it well and comfortably.  If you do not learn to use those techniques, it will behave badly (to your perception).  Once again, I urge you to watch Larry Smith's video (mentioned above) end-to-end.  He is using the larger RO 150, but the techniques are very similar.  You might want to mention what part of the globe you inhabit.  There may be Festool users near you that may be willing to assist you.

I started with the RO90 and while it is a bit of a handful in the beginning, you can get used to it. The main thing with all of them is that they don't appreciate getting tilted. Whether it is actually physically tilted of just more pressure is exerted in one section of the pad, the effect is the same. It "kicks back" against that pressure. That's why the bigger units do this less because there is so much more area on the pad itself. You are putting the pressure further and further away from to center point.
Accordingly, the RO90 is more intense than the RO125. The reaction isn't any worse, it's just easier to get it to react.
Having owned the RO90 for several years before buying the RO125, I have never had any issue with it.
Stick with it and once you "get it", you'll never think about it again.

Thanks all.  I spent a few hours the other night with your advice trying to master it.  Still a ways to go it would appear, but I will say as Bertotti mentioned, it is actually a lot easier to handle in Rotex mode than in the orbital mode.  In orbital, there are just so many places on my pieces where it just tries so hard to keep me away.  Removing all downward pressure definitely helped as well as holding it by the plug/hose area.  Even still, there were some places I just couldn't get it to stop bucking without applying the faintest amount of upward pressure (lifting it).  Additionally, I found that if when it's not dead flat on the workpiece it operates kind of smoothly.  It's not bucking around but obviously, it's not sanding flat and evenly if you're doing that.  But when I get it do be perfectly flat on the piece that's when it really digs in and fights me.  I think the next thing I'm going to try is the rotation that mrB mentioned.

One thing I've kind of been wondering, as a complete aside, is why does the 125 exist?  It's really powerful and difficult to handle making it not super well suited for smaller pieces.  It sounds like it is, with practice, good for larger, heavier pieces.  But if you are working on larger pieces with more square footage, then the 150 seems like a much better tool.  More sanding surface area and much more pleasant to operate.  Just wondered if anyone had any thoughts as to what the 125 offers aside from a slightly lower price point than the 150.

I just received my RO125 this afternoon and I thought I got lemon, but seems like maybe it's operator error at this point.  Having all the same issues. I bought it to for sanding a endgrain cutting boards.  I needed to get rid of the marks from running them thru my Drum sander to flatten them out after the second glue up. It did them job, but darn I felt like I fighting it the whole.  My hand was sore and only just stopped hurting about an hour and half later.  I give all these tips a try tomorrow.  Especially the Dust extraction settings.  Had the vac at full suction.  I'm guessing though that some the issues is that I was sanding end grain.  Or am I wrong about that?

Cheers! 

On the RO150 I haven't tried the side handle nor the accessory front handle. I didn't buy it. I have my ct 26 set just below half, maybe a bit lower on coarser grits. I also started turning the ct down when using the belt sander and it actually helped with the dust extraction on it as well. Since getting the RO150 I haven't used the belt sander. Now all the sanding I did was on my hands and knees, I can only imagine it is a lot easier upright. Like I said I find orbital harder to use but in rotex I can one-hand both sanders with no issues now. Just take a break when you first start using it to let the muscles in the wrist build up and rest. I could use a belt sander all day but that rotex killed me at first until I got used to it. I don't know that end grain is harder to sand than flat grain but it may be simply because the heavier grits can grab a bit more.