RO125 leaving 5" diameter scratches in ((((( pattern

[Narwhalmfg]

I recently made the upgrade to the RO series from just having an ETS125 in my toolbox. Sadly, i am not very satisfied with it yet. I No longer have the little(but massively annoying) swirly "pig tails" but I now have larger scratches going cross grain. I must be doing something wrong because it seems like a lot of people recommend this sander as the answer to common sanding problems.

I have looked at a couple threads on this issue and have done most of what people say. I even watched the video of Larry Smith and did exactly what he did. I typically start with 120 grit and go to 220 before Poly. Do you only get rid of the large scratches by going up to 400? Is there some simple thing that I am not doing/considering? Why have I not seen this problem with any porter cable/dewalt sander? I love the festool product and the dust extractor but I don't like feeling that I don't know how to sand a piece of wood anymore.

any info/advice would be greatly appreciated. Thanks!!

 

[bobfog]

I recently made the upgrade to the RO series from just having an ETS125 in my toolbox. Sadly, i am not very satisfied with it yet. I No longer have the little(but massively annoying) swirly "pig tails" but I now have larger scratches going cross grain. I must be doing something wrong because it seems like a lot of people recommend this sander as the answer to common sanding problems.

I have looked at a couple threads on this issue and have done most of what people say. I even watched the video of Larry Smith and did exactly what he did. I typically start with 120 grit and go to 220 before Poly. Do you only get rid of the large scratches by going up to 400? Is there some simple thing that I am not doing/considering? Why have I not seen this problem with any porter cable/dewalt sander? I love the festool product and the dust extractor but I don't like feeling that I don't know how to sand a piece of wood anymore.

any info/advice would be greatly appreciated. Thanks!!

Are you in forced rotation mode or random orbit mode? If forced rotation this might explain the longer arc shaped scratches and explain why you never had this problem with other sanders.

Secondly you're probably starting too high. 120 is quite fine and depending on the state of the wood before you may not be getting the initial scratch marks out so the mark you see might not be being put in by your RO 125, but more to the point, not being taken out in the first place.

Also jumping from 120 straight to 220 is far too big a leap, you should be going 80, 120, 150, 180, 220.

Finally the RO style sander does taken some practice and you could be not keeping the pad perfectly flat and causing the edge of the pad/paper to dig into the wood.

 

[Holmz]

I recently made the upgrade to the RO series from just having an ETS125 in my toolbox.
...

The ETS EC would be more clearly an upgrade for a finish sander.
The RO is an upgrade if you need RO mode.

I typically go 180 to 220.
If you are going 120 you probably need to finish it in non twist mode, or do the 220 in twist mode first.
I'd shove a 180 in there if you have some.

 

[ear3]

Just to clarify, since it's not totally clear from initial description -- do you go straight from 120 to 220, or do you step up through intermediate grits?  If not, then the advice given by others should be followed.

Are the scratch patterns you see consistent, or are they random suggesting the presence of debris/imperfections?  Sometimes the paper can get torn at the holes, which can mess up the surface.

As far as normal use, I have noticed visible scratch patterns left by my RO150 up to 180, but by the time I get to 220 these are usually gone.  When I was using the RO150 as my main sander, I tended to do the last one or two grits in RO mode, rather than gear driven mode.  There are people here who swear by the results even in straight gear driven mode, so I know its possible to get "swirl-free" sanding that way.  All the same, my go to sander these days is the ETS-EC 150, and I reserve the RO150 for heavy duty or low grit applications.

 

[Peter_C]

If you are starting with 120 grit the wood must not need much sanding. If like the OP I had both an RO125 and an ETS125, I would switch between them. Not even sure I would use the RO125, but maybe just the ETS125. Again it depends on the woods smoothness. Might only hit sections like joints with the RO125.

One thing to be careful of is how hard you press down. If to much pressure is applied it will leave gouges every time, especially in Rotex mode. Barely rest your hands on the sander.

If sanding in Rotex mode with 125 grit, switch sanders or at least switch the RO125 to random orbit mode before changing grits.

When changing grits make sure to clean the wood surface off in order to remove loose grit from the previous sanding.

If you switch grit up and go again in Rotex mode make sure to follow up with random orbit mode.

Learn to feel the sandpaper with your hand so you can tell when it is worn out, comparing it to a new sheet. I find many folks use their sandpaper long after it is worn out. You could try a new sheet when switching to random orbit mode.