Help! Swirls in flooring using orbital sander

[Kevin Murdock]

All,

Looking for help because I can't figure out what I'm doing wrong.

I laid 3/4" brazilian cherry (jatoba) and rented a "U-sand" random orbital floor sander from HD.

After progressing through 24, 40, 80, 120 grits I got swirl marks in the floor after every pass. After 120 grit the swirl marks are lighter but still visible. Sandpaper is Norton brand.

Any suggestions? Anyone else seen this?

Thanks!
/Kevin

[Corey Hallagan]

Hmmm.... I have used that same sander and didn't get any swirls. Maybe you started too coarse. We used 40, 80 & 120 on the oak floor I refinished which had a 30 year old finish on them. Did they reccomend you start so coarse with a brand new floor? I would of thought 80 and 120 would have been fine or even just a 120 sanding.

Corey

[Kevin Murdock]

Corey,

Thanks for the quick response. It isn't a matter of starting too coarse. When we noticed the problem we tested out the different grits on "virgin territory" and the swirls were there even with just the 120 grit. No matter which grit we used we got swirls. Thought perhaps it was a problem with the machine so we switched it out for another one but we're still seeing the swirls.

We're really racking our brains on this one. When we finished the floors upstairs we used the same type of sander and didn't have any problems up there. Really at a loss here.

/Kevin

[Richard McComas]

How fast are you moving the sander? Just guess here because I have never use a floor type orbital sander but I have use the hand held type.

With a hand held sander I found that if you move the sander over the surface to fast the sander doesn’t have time to cut like it is designed to and will leave small scratches. By moving to fast you may be dragging the grit across the wood not letting it cut as it should.

[Kevin Murdock]

Hi Rich,

We've tried fast, slow, somewhere in between. Same result. Can't figure out why this time should be any different from the last.

/Kevin

[Corey Hallagan]

Sounds like an orbital action just isn't compatibale with that particular wood. Maybe go with a drum sander for a final pass?

Corey

[Steve Rowe]

Kevin,

I haven't used Jatoba but have seen this in cherry following ROS use. One tip I picked up from a professional finisher is after all your power sanding is done with a ROS, go one grit coarser and hand sand with the grain. I really didn't believe this until I tried it, it really does take out the swirls. This has worked extremely well on my furniture but it sound like a lot of work on a floor. You may want to see if they have a straight line sander to do this.
Good luck,
Steve

[Mike Cutler]

Kevin. I've never done a floor, but I've fiished a lot of Jatoba. 120 grit is still to coarse, even for furniture. I sand up to 180 on furniture, then lightly dampen the wood to raise the grain, start at 150 and do it again up to 180.
Jatoba is a very forgiving wood when it comes to finishing, the swirls that you see may not be visible when the sealer and finish coats are applied, but like I said, I've never done a floor.
Don't know if this helps or not, good luck

[Jim Becker]

Are you cleaning the floor between grits to insure any of the previous grit that fell off the abrasive substrate isn't being dragged along by the next pass?

[Kevin Murdock]

Thanks for all the inputs! I think we're going to try a different type of sander next weekend but will definitely keep all your advice in mind.

Thanks again,
/Kevin

[Andy Halterman]

Kevin,

Jatoba can be a bit unpredictable at times. I've had some real horror shows with it in the past. Other times, I'd swear it was the best flooring out there. I'd try water popping the floor and then use a buffer starting with a 100 grit sanding screen and go up to 150. That should (hopefully) get rid of your swirls. The suggestion about vacuuming in between cuts is a good one as I've had that happen to me a time or two.

Buena suerte.

Andy Halterman

Raining as it has done nearly every day since the beginning of June in Hendersonville, NC™