When using a finish that calls for only sanding up to 150 grit (Waterlox in this instance), how do you eliminate swirl marks from a random orbit sander?
I had only been doing this for water based finishes, but I’ll give it a shot this time aroundDid you raise the grain in between grits? I have found by wiping the wood with a damp shop rag helps to raise the grain and also get rid of the more course grit from the last grit before you move higher. Let the wood dry to the touch before sanding at the higher grit. You may be putting too much pressure down on the orbital sander and may want to only sand with the grain. Hope some of this is helpful.
Sanding to 150 is an industry standard for building a finish in the cabinet and furniture industry. Once finish is applied the sanding becomes 320, 400, 600.
This may explain my continuing swirl mark issue. I don't press at all but still have marks. I noticed they were all small diameter which implies they come from the center of the wheel. some ROS have a gap in the center but mine didn't. cut one into mine which seemed to help. But over suctioning explains the original problem.Another suggestion is to not use full power on your dust extraction. You can create a variable leak between the vac and the sander with a 3/4" hole drilled into an inline connector. Cover with masking tape when you need the full power. This lightens the downforce on the abrasive creating less swirls and also pills/boogers of finish on the paper if you are stripping a piece. I use a wye from Fein with a cover over the unused side of the wye.
Another suggestion is to not use full power on your dust extraction. You can create a variable leak between the vac and the sander with a 3/4" hole drilled into an inline connector. Cover with masking tape when you need the full power. This lightens the downforce on the abrasive creating less swirls and also pills/boogers of finish on the paper if you are stripping a piece. I use a wye from Fein with a cover over the unused side of the wye.