ETS 150/3 EQ leaving ridges

manitario

Member
Joined
Mar 13, 2026
Messages
1
Hi,
I have an ETS 150/3 EQ that is leaving a striped sanding pattern (please see pic). Only is apparent after the first coat of finish. I've had this sander for ~13y and have never had this problem; I tried replacing the sanding pad, and also the hook and loop attachment which hasn't fixed the problem; both are Festool brand, as is the mesh sanding abrasive. I've sanded the same way with this sander since I bought it, using the same type of pad, same hook and loop attachment pad and same mesh abrasive on every project and this is the first time encountering this issue. No change in suction (I have a FT dust extractor) or sanding speed. No visible swirl marks. I sand every project starting with 80g working up to 220g, doing overlapping passes across the grain and then with the grain.

I'm baffled, the has been a fantastic workhorse of a sander that up until this project has left a flawless surface. Any insight or suggestions as to why this is happening would be greatly appreciated!
 

Attachments

  • IMG_3183.jpg
    IMG_3183.jpg
    388.2 KB · Views: 21
Can’t think of any way the sander could be responsible. More likely to be the grain structure of the wood. The same thing that causes “blotching” in cherry which is really the waviness of the grain abruptly reflecting light in a different direction.

A test is to inspect from 180 degrees around and look for the dark areas along the “ridges” to shift to the other side of the “ridge”.
 
Those scallops look like they come from a thickness planer. If so, its feed roller needs adjustment.

Regards from Perth

Derek
 
Back
Top