Rotex sanding tips?

[JonSingh]

Hey All,

I picked up a 5" Rotex that's been working great but I myself have been having some issues both sanding in rotex mode and fine sanding mode. I tend to leave some swirly marks here and there that i have to fix later and i cant quite figure out where or why its happening sometimes.

Also I've found that when I sand I sometimes leave the material less flat then it was before, this is especially true on anything soft, where the grain itself stays raised but the in-between "white space" sands lower.

Anyways, just hoping for some practical sanding tips, experience/advice.

Thanks,
Jon

 

[Peter_C]

Cut fast with a course grit in Rotex mode to level the surface. Move up to the next grit quickly. You can switch between Rotex and orbital modes as needed. If you have swirl marks that aren't going away, move back down in grit. Turn your dust collector down especially in the finer grits. If you don't have adjustable suction capability, bleed off suction with a hole in a pipe or some other way. Put the handle on the sander and hold it by the hose at the back gently, no pressure for sanding with finer grits. Keep practicing!

Watch a bunch of youtube vids...

 

[AlexThePalex]

I picked up a 5" Rotex that's been working great but I myself have been having some issues both sanding in rotex mode and fine sanding mode. I tend to leave some swirly marks here and there that i have to fix later and i cant quite figure out where or why its happening sometimes.

We recently had a pretty lengthy discussion about it here, lots of info about it.
https://www.festoolownersgroup.com/...ar-epoxy-resin/msg618531/?topicseen#msg618531

Also I've found that when I sand I sometimes leave the material less flat then it was before, this is especially true on anything soft, where the grain itself stays raised but the in-between "white space" sands lower.

That's something that can easily happen with any random orbit sander, and especially with the RO125. It is a powerful machine and if you leave it too long in one spot you'll get a dimple. Always keep it moving and make sure you keep the pad flat.

If you work on softer material, there's an interface pad you can buy which is softer than the sander's own pad.

 

[mkasdin]

I picked up a 5" Rotex that's been working great but I myself have been having some issues both sanding in rotex mode and fine sanding mode. I tend to leave some swirly marks here and there that i have to fix later and i cant quite figure out where or why its happening sometimes.

We recently had a pretty lengthy discussion about it here, lots of info about it.
https://www.festoolownersgroup.com/...ar-epoxy-resin/msg618531/?topicseen#msg618531

Also I've found that when I sand I sometimes leave the material less flat then it was before, this is especially true on anything soft, where the grain itself stays raised but the in-between "white space" sands lower.

That's something that can easily happen with any random orbit sander, and especially with the RO125. It is a powerful machine and if you leave it too long in one spot you'll get a dimple. Always keep it moving and make sure you keep the pad flat.

If you work on softer material, there's an interface pad you can buy which is softer than the sander's own pad.

You might try blowing (air compressor] or wiping with a cloth between grits. You might have impurities on the surface. I think the RO has a 5mm stroke. For finer grits I use a 3mm stroke sander like the ETS-125. I like to run my stock through a planer, with sharp knives. At that point it’s almost arbitrary to sand? If I do I’ll start at 180 and go to 220 if it’s a clear GF Poly finish. Flat sawn like pine will sand out quicker in between the grain? I’m unaware that the interface pad will reduce the understanding in the softer wood, I need to step up my game if it’s true. As was mentioned turn down the vacuum and suction on the DT, since that pushes down on the work piece? If I had to guess your pushing down on the sander,, let the sander do the work and the granat paper. No need to apply pressure, experiment with different species of wood, feed rate and volume (speed setting)?

 

[ear3]

In case it's not mentioned in the thread linked to by Alex, the pencil trick is very useful to prevent oversanding, i.e., marking the surface with a pencil and stop going over that surface as soon as the mark is removed.  Even with this method, though, it is very easy to dish the surface with something as aggressive as the Rotex if you're not careful.  For the longer term, and especially for larger sanding surfaces, you might look into getting a half-sheet sander like the RS2 (or another brand's equivalent).  I now start with the RS2 almost exclusively when dealing with wide lumber or panels made from multiple edge-joined boards, then switch over to an ROS at or after 150 grit.

Hey All,

I picked up a 5" Rotex that's been working great but I myself have been having some issues both sanding in rotex mode and fine sanding mode. I tend to leave some swirly marks here and there that i have to fix later and i cant quite figure out where or why its happening sometimes.

Also I've found that when I sand I sometimes leave the material less flat then it was before, this is especially true on anything soft, where the grain itself stays raised but the in-between "white space" sands lower.

Anyways, just hoping for some practical sanding tips, experience/advice.

Thanks,
Jon

 

[aloysius]

Your 125mm Rotex has only 3.6 mm of eccentricity, meaning that it's slower to abrade than many. 

If you're having trouble with summer wood abrading faster than denser winter wood rings (a common phenomenon with Gymnosperms), then try a harder pad, kept precisely flat on the workpiece surface.

Above all else keep it flat & in constant motion sweeping across, along or in non-overlapping "figure 8s" evenly over the whole surface.  It may also help to start & stop the tool whilst in contact with the workpiece.