Orbital Sanding Stroke

[wsrhue]

I'm considering a new orbital. I've had both 3mm and 5mm stroke air sanders for years and love them, but I'm planning to go with electric. I have the rotex 190 that gets a lot ion use in my shop and I like it but the 5mm orbital strokes are visible when sanding to 150 in preparation for a hardwax oil. In the past I used a wiping poly where I sanded to 220 and never had and swirl marks. Now after sanding with the rotex, I switch my dynobrade 5mm up to 220, and I still need to come back and hand sand with 150 for the final pass with the grain to remove the swirl marks.

The problem is probably the Hardwax Oil finish but I've planning to stick with it at this point.

I've always thought of the 3mm stroke sander as being important in the finishing process for higher grits. What are your thought on 3mm stroke vs 5mm stroke sanders? When do you use one over the other?

 

[drw]

While I am no expert on this topic, I do own both 3mm and 5mm stroke sanders. I typically use the 3mm for sanding raised grain after the first application, and all subsequent applications, of finishes. The 5mm is typically used in preparing surfaces for the first finish application. While this sequence has worked well for me, it may not be the way it is supposed to be done.

 

[Wiley's Woodworks]

I wound up with multiple electric hand sanders in a bundle purchase. It took a few tries, but I figured out the best sequence. I use a ROS, probably a 3mm stroke, with all grits up to 220. I then finish the sanding with 220 grit on a square pad DeWalt sander, moving it with the grain. You can feel the speed difference in the pad motion, so I assume it has a shorter stroke. The result is a smooth surface, ready for finish, with no swirl marks. If I have to sand between coats of finish, I use the pad sander with the used 220 grit sandpaper for early coats and 320 grit before applying the final coat and move the sander quickly over the surface.

 

[Gofor]

Check your technique. To reduce swirl marks, you start/stop an air sander on the surface, However, with the brakes (anti spin ) on the electric sanders, you start and stop with the sander off the surface for the least amount of swirl marks.