Getting small swirl marks with Festool RO150 Sander

[Prizen]

Hi All

I am continuously seeing swirl marks after sanding with my Festool RO150. I have tried turning down the vacuum power to the lowest setting, but these marks are still present.

Anyone experience this and manage to correct it?

Cheers

 

[MikeK]

I've never used my RO 150 for finish sanding, but I suspect it is too heavy for what you might be trying to do. I use the lighter ETS EC 150 for finish sanding and have never seen swirl marks.

 

[custard]

What grits and what type of abrasive paper are you using? And are you absolutely sure it's on the finer "random" setting? Festool's pictograms aren't very clear so it's easy to get that one wrong.

 

[Prizen]

I use festool granat 100 120 150 180

 

[Ollie78]

A way to prevent this is to "float" the sander accross the work. Just really lightly control its movement with no downwards pressure at all.

Ollie

 

[custard]

I'm as confused as you are Prizen, I use a wide range of Festool sanders, including the RO150. The main reasons for swirl marks are either too high vacuum pressure or inappropriate grit/paper choices, and it seems neither of these apply in your case,

What type of timber are you experiencing problems with, and are the swirl problems visible on the bare wood or only after a finish is applied?

 

[Nelsun]

I've had swirls myself and found dropping the suction way down (you've done this already though) and lightly guiding the sander (a hand over the top moving it with little to no downwards pressure and the other hand under the hose port to stabalise) to help the most. The temptation to press down on the initial lower grits is high... but do resist as this can induce heavier scratching that takes some time to get out.

You've not said what material you're sanding but, for bare wood, I've always used Ruben / Ruben 2. I've never used Granat which looks to be more of an all-rounder. I'd doubt that's the cause of swirls though.

This may be anecdotal, but I've found swirls more likely in softer woods... or that could be because that was what I used the first time I got the Rotex and only noticed the swirls after applying the finish. Oops.

It may be worth checking the state of the paper after sanding as well. If it's got wee lumps in it then that will not Be Good e.g. with too high a speed or staying in one area too long it's generating too much heat and melting paint which then accumulates and starts clogging up. The same can happen with wood but it's much less likely.

It sounds like you're on the right track and I'd guess at taking a lighter touch as suggested above may get you going. You've already dropped the suction which is a big step in the right direction.

 

[sometimewoodworker]

I've never used my RO 150 for finish sanding, but I suspect it is too heavy for what you might be trying to do. I use the lighter ETS EC 150 for finish sanding and have never seen swirl marks.

As the RO150 can be used to get a mirror smooth gloss finish, using it in geared mode and with much higher grits, it’s definitely not the weight.

 

[Lefley]

MY friend got this. He was to high of suction and the weight of vacuum hose was tilting sander getting swirls. Uneven weight on side of sander.

 

[Peter Sefton]

If you use abrasives with torn edges these can leave swirl marks.

 

[PerryGunn]

As part of a process of elimination, why not try a test without the vacuum hose attached
- if the swirl marks don't appear, you've found the culprit and can concentrate your attention in either reducing suction further or rerouting/supporting the hose.
- if they still appear, you can investigate other causes e.g. trying a different abrasive, changing your grip/pressure on the sander