RO125 pad not rotating in Fine mode

[magnuswyze]

[attachurl=1]Hello,

I'm wondering if I can get some help from anyone that has RO125 to review the attached video link below and let me know whether it is in normal operation please.

I have been sanding with the finish random orbit sander ETS125 and Dewalt for long time and have always had very good results in finish.  Recently I bought RO125 for the combo rotex and ROS functions in one.  To my surprise, the finish with RO-125 in "fine" mode has lots of scratches.  I've searched forums and youtube videos for proper handling/holding/CT vacuum power setting with rotex, and tried them all, but scratches still exist. 

One observation that I have is that the pad was not always rotating during sanding (rotating RPM is not constant; more often it is not rotating at all; only the fine orbiting motion).  After many tries, I gave up and fixed the scratches with my ETS125 using the same paper that I peeled off the RO125.  With the ETS125, the pad was always rotating smoothly and glide over the surface.

I understand RO125 is more bulky and more difficult to handle, but I think I handled it correctly and flat to the surface.  For my final test, I turned on my RO125 under no load, and saw that it didn't even rotate as shown in the attached video.  This is quite different behavior from my ETS125 as well as my cheap Dewalt.  I sent the tool back to Festool for service and it was returned with note "Machine operated and functioned as intended upon arrival".  So I'd like to get feedback from users in this forum if the same behavior is normal or not.  Thank you very much for everyone's time.

video link:

Note: Sanded material: walnut table top
RO125 speed setting: 6
Feed speed: 1"/sec
Abrasive paper: Mirka Abranet 100, 120, 180 used with Mirka protection pad (scratches exists at each grid).  I dropped back down from 100 when I fixed the scratches with ETS125.
CT vacuum setting: 9 o'clock (same as my ETS125 setting).  I tried the lowest setting 7 o'clock and situation did not improve.

 

[Crazyraceguy]

That does seem odd? Though I very rarely use mine not in Rotex mode. I much prefer the ETS EC 125 for the finer finish sanding.

 

[Frank-Jan]

I think this is caused by the pad brake being too stiff. The pad brake is the rubber flange that rests on top of the sandingpad, around the outer edge of the extraction holes. This pad brake prevents the pad from turning really fast when the sander is not in contact with material.
I use my rotex 150 mainly in rotex mode, and when I do use the "fine" mode the pad brake is not effective anymore. It will not spin constantly when sanding, but when I run the sander when it's not in contact with the material it will spinn really fast.

I remember a bunch of threads about the "break in" procedure, where people hang up their sander with a piece of rope and leave it running for a bunch of hours, I searched for it, and came across this thread

 

[bobtskutter]

I've been building a desk for my son out of an old Beech table.  I was using my RO125 with Granat P120 and the soft pad in RO mode.  I was getting minor swirl marks.  I changed the sanding sheet for a fresh disk of Granat P120 and cleaned off any loose dirt from the work piece.  I held the sander gently and didn't apply any downward pressure, the swirl marks went away.  I suspect I had bits of rough dirt trapped in the sanding disk.
Regards
Bob

 

[magnuswyze]

Thank you very much for your kind responses.  I apologize for my late reply as I'm currently traveling.

[member=1993]Frank-Jan[/member],  i also read about those break-in period threads, and I'm thinking about doing it too.. but I dont quite understand why my ETS125 doesn't do/need that. 

[member=76043]bobtskutter[/member]  do you know i your RO125 also not spin constantly like mine and frank-jan in fine mode?  O also dont put downward pressure when I sand.. just guiding the sander so only its own weight.

I think the general conclusion from your 3 feedback is rotex is generally used in rotex mode, and use the fine sander for fine sanding.. 

Thank you.

 

[bobtskutter]

With the RO125 in fine mode the pad spins when the sander is in the air, not in contact with the work piece.
The pad spins occasionally when the sander is in contact with the work piece.
regards
bob

 

[Crazyraceguy]

I checked mine today after reading about this. It seems that maybe this is an unfair test. Meaning that the results are misleading. When allowed to run "free", what it does is rather irrelevant. If you touch the sides of the pad, like you are trying to stop it, you will see what it actually(meaningfully) does.
Maybe if you put a small mark on the pad with a Sharpie, you will see which way it is moving when the load it applied.

 

[magnuswyze]

Thank you [member=76043]bobtskutter[/member] and [member=58857]Crazyraceguy[/member] for testing.

[member=58857]Crazyraceguy[/member], I'm sorry I didnt mean to mislead.  The no load test I did amd in asking for is to eliminate my technique as reason for pad not rotating while sanding (e.g. common sense would point to pressimg down too much or slightly tilting).  I honestly didnt know whether the no load test is appropriate or not.  Its just something I observed as something different compared to my ETS125 and dewalt.
But the fact that [member=76043]bobtskutter[/member] comments about rotating occasionally during sanding and festool service said mine was working as intended, it seems like it's normal operation behavior for Rotex.
I dont know how that behavior can not producing scratches or swirl marks, but my key takeaway is rapid stock removal use rotex mode, and fine sanding use separate ETS or ETS EC sanders. 
Again, thank you very much for the time everyone took to answer my post. I have to say I always learned a lot from this forum.

 

[bobtskutter]

Hay Magnuswyze,
I'm no expert with the Rotex.
Just go easy with it.
I was sanding some beech table tops the other day to remove the lacquer finish before applying PolyX.
I used the RO125 in Rotex mode, started at P80 to remove the laquer.  I then cleaned the work piece to remove any remaining dirt or grit by wiping it gently with my hand / cloth.  I then switched to P120, still in Rotex mode and went over the wood to remove the scratches from the P80.  I moved the sander slowly, keeping it flat and not pressing down.  I then changed the disk for a fresh P120 and repeated, and finished with P180.
It wasn't quick but I did end up with a surface that was free from scratches.
Regards
Bob

 

[magnuswyze]

[member=76043]bobtskutter[/member] .. thank you for sharing your tips.  I'll definitely give the rotex mode a try (not just for rapid stock removal).

Have a good day.