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sander issues

Dan Member

Hi All
we are having issues with little sanding circles on some of our finished products its not just coming from one sander as i have found some with the 3/16 and 5/16 sanders.
We use a dust removing vacum and good quality disc's
the problem is not noticed until the stain is applied.
any help would be appreciated.

2/12/15       #2: sander issues ...
Leo G

What sander?

2/12/15       #3: sander issues ...
Jim Clark

Most times it's from the operator
going back and forth to fast.
Like they do on TV shows.
You can't do that with RO sanders.
You have to go slowly like the
owners manuals instruct.

2/12/15       #4: sander issues ...
Dan Member

Hi leo
The sanders are a dynabrade 6" and we have one master craft 5" random orbit sanders.

2/12/15       #5: sander issues ...
Leo G

The dynabrade is an excellent sander, I don't know about the Master Craft.

I'm assuming it's an air powered sander. They do wear out. Especially if you skimp on the oil. The bearings become worn and the RO pattern becomes distorted.

But the likely answer is what Jim said, operator error. It sounds like you are using a vacuum on them which should remove any particles that might cause the swirl marks.

Ask them to slow down. Usually my sanding procedure is go against the grain in 1/3rd steps. Then do a circular pattern overlapping 50% and then with the grain in 1/3rd steps.

If you are only willing to do one of them choose the circular pattern motion. And tell them to change the paper like its free. Over using the paper is a waste of money. Causes more problems then it's worth.

2/12/15       #6: sander issues ...
herb johnson

with my guys it is usually caused by them pressing to hard on the sander

good luck


2/12/15       #7: sander issues ...


As important as the quality of disc is the type of abrasive, hopefully your using an Aluminum Oxide (open coat) If your using an orbital sander go with @ 3/32 orbit and progress through your grits properly such as 100,120,150 ect; also the type of stain plays a role. if there's dye in the stain solution your more apt to notice those swirls if its a pigmented stain only not so much.....good luck!!

2/12/15       #8: sander issues ...
arthur grudko

This is why National Detroit straight line pneumatic sanders are still being manufactured and sold.

2/12/15       #9: sander issues ...
Adam West  Member



Orbital marks or swirls are a normal part of using random orbit sanders. I have written extensively about methods involving wide belt sanding to try and minimize them, but they are a fact of life.

Go to your local football stadium and plow the field without leaving a furrow.

The best you can do is create a surface that requires as little random orbital sanding as possible and get it done quickly with as little pressure as possible.

A wide belt does the flattening for you so you just remove scratch pattern. You will have very little swirl until you have removed the scratch. Once you are sanding a clean flat plane you are driving the grains into that surface and creating swirls. The more you sand the worse it gets.

If you are relying on your random orbit sander to flatten the surface and stepping down grits, you really can't help but end up with swirls on some level.

A properly maintained sander running 90 psi at the tool, a clean, flat back up pad, and a quality disk help. Use very light pressure and smooth, slow passes on your finishing pass to help minimize them.

Beyond that, hand blocking after random orbital sanding is the only sure way to remove swirls.

2/12/15       #10: sander issues ...
Leo G

My Mirka Ceros sander is virtually swirl free. I don't recall the last time I've seen a swirl since I've gotten it.

2/13/15       #11: sander issues ...
Jim Clark

I don't have any swirls,
( that I can see anyway)
I go slowly back and forth and final
sand to 180 grit.
I don't remember ever having a problem
as long as I sand past 150.
But all my sanding is with electric RO.

2/13/15       #12: sander issues ...
Dan Member

Lots of good advice Thanks !
I will for sure be looking to change the way I am working the sander as I have also been training people and that is now rubbing off on them.
I have been in the wood work industry for 20 Years and feel that sanding has always had room to be improved this is one of our major goals to take the quality of the finished product to the next level as its now my product thats going out the door.
producing a top quality cabinet does take some real skill in the sanding and the spray finish department.

2/13/15       #13: sander issues ...
Paul O in Ontario Member

Sometimes the vacuum system, especially if a high powered shop vac, is too powerful and literally sucks the disc down onto the surface and can give swirls (same process/effect as pressing too hard). Happened to me when I got a new, more powerful shop vac.

2/14/15       #14: sander issues ...
Kevin Member


Wide Belt 120/180
Dynabrade 150 then 180

Veneer: Dynabrade 180

Right to stain, no visible swirls

Swirls are from either pushing way too hard or running a sanding disc until the end of time without changing it

Also could be cheap vacuum discs, I don't like Vacuum Sanders personally

My 2 cents

2/17/15       #15: sander issues ...
Jim Clark

If you ever watch a TV woodworking show
you'll notice that most times they sand
by going back and forth real fast and long
arcs of travel, that's a guarantee of getting
swirls. Small back and forth distances and
doing it slowly will keep you from getting
swirls, even when pressing harder than
you should. Even the tools directions
point that out.

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