You are not logged in. [ Login ] Why log in
(NOTE: Login is not required to post)

What causes swirl scratches?

Mike Fuson

What actually causes swirl scratches when using a random orbit sander? Pressing down to much or not enough? Going over the wood to fast or to slow? We are using a ceros sander with 120 grit. I don't do the sanding but the guy that is has been with me for years. Doesn't happen all the time but certain stains tell on us.

9/3/17       #2: What causes swirl scratches? ...

With an pneumatic sander the first thing to look at is low pressure. Electric... not sure pressing to hard. Cheap paper that has "big grit" mixed in. Dirty disk under the paper. Lots of things can cause it.

9/4/17       #3: What causes swirl scratches? ...
door shop guy

Go down to 150 or do you always stop at 120? 120 is too rough.
What brand discs are you using with the Ceros?

9/4/17       #4: What causes swirl scratches? ...
Mike Fuson

I've used disks from industrial abrasives for years, best I've found. I think it's Indasa or something like that, got a rhino on the box I think. I do stop at 120 grit and have for the last 20 years mainly because when you go finer the wood is more likely to repel stain than soak it up. Hard to achieve a rich dark color. By the time I'm through the schedule my finishes are slick.

9/4/17       #5: What causes swirl scratches? ...
Paul Eichenlaub  Member


I always look at the speed I moving the sander. Sometimes moving to slow with the sander causes it along what has always been said.

9/4/17       #6: What causes swirl scratches? ...
Matt M

Good info above.

My experience:

Some sanders seem to be worse than others. I'm happy with Dynabrade air sanders but there are so many types of electrical sanders that I cannot recommend one over the other. Except, quit using electric lol.

My most common problem is the paper. I've found a small handful of brands that give me good results (usually the green emerald colored pads) on Dynabrades. Using a good quality paper has been our #1 way to stay consistent.

But like said above-- using excess pressure will do it. Sanding in a dusty environment will do it (we use downdraft tables, which is a huge help). Having a worn velcro or PSA pad will do it. Getting a lump of dust under your velcro or PSA pad will do it.

On oak, it can be really tricky to hide them even on the best days with the best equipment.

9/4/17       #7: What causes swirl scratches? ...
door shop guy

Im pretty sure that Indasa does NOT have a multi hole disc (Multi hole being a LOT of really small holes ) If you are only using a 5 or 8 hole then that causes dust collection to not be very good.
The only discs i have found to be excellent with the Ceros are Emerald multihole and the 3m Purple multi hole and those are also the only two companies that i know of that make a multi hole disc.

9/5/17       #8: What causes swirl scratches? ...
Jim Clark

The no. 1 cause is going back and
forth to fast, like you see on TV
woodworking shows.
Read the directions with the sander,
they always tell you to go slowly.

9/6/17       #9: What causes swirl scratches? ...
Chris Windsor

From my experience, two things cause swirls: moving too fast and/or tipping the sander causing it to sand on the out edge of the abrasive.

9/10/17       #10: What causes swirl scratches? ...

along with the above suggestions; when I was a corian certified installer we were told it was inconsistent grit in the sanding paper which is why the micron graded sandpaper was recommended.

9/10/17       #11: What causes swirl scratches? ...

All good responses. 120 grit an in between paper as far as aggressiveness. We all sand by the numbers. Our schedule is typically 100/150/180 for stain grade. In order to eliminate the previous depth of cut you need to sand to that depth to get rid of that scratch.If you skip one spot depth wise you will be left with swirls typically from when the sander initially touches the surface. The random orbit sander initially is a rotary sander until it makes that first cut then switches to true random orbit on the next rotation or two.

My first suggestion would be to wipe the entire surface with denatured alcohol after finish sanding to see if you missed a spot. This is common practice for our stain jobs.

  • Post a Response to this thread
  • Notify me of responses to this thread
  • Subscribe to email updates on this Forum
  • To receive email notification of additions to this forum thread,
    enter your name and email address, and then click the
    "Keep Me Posted" button below.

    Please Note: If you have posted a message or response,
    do not submit this request ... you are already signed up
    to receive notification!

    Your Name:
    E-Mail Address:
    Enter the correct numbers into the field below:

    Date of your Birth:

    Return to top of page

    Buy & Sell Exchanges | Forums | Galleries | Site Map

    FORUM GUIDELINES: Please review the guidelines below before posting at WOODWEB's Interactive Message Boards (return to top)

  • WOODWEB is a professional industrial woodworking site. Hobbyist and homeowner woodworking questions are inappropriate.
  • Messages should be kept reasonably short and on topic, relating to the focus of the forum. Responses should relate to the original question.
  • A valid email return address must be included with each message.
  • Advertising is inappropriate. The only exceptions are the Classified Ads Exchange, Machinery Exchange, Lumber Exchange, and Job Opportunities and Services Exchange. When posting listings in these areas, review the posting instructions carefully.
  • Subject lines may be edited for length and clarity.
  • "Cross posting" is not permitted. Choose the best forum for your question, and post your question at one forum only.
  • Messages requesting private responses will be removed - Forums are designed to provide information and assistance for all of our visitors. Private response requests are appropriate at WOODWEB's Exchanges and Job Opportunities and Services.
  • Messages that accuse businesses or individuals of alleged negative actions or behavior are inappropriate since WOODWEB is unable to verify or substantiate the claims.
  • Posts with the intent of soliciting answers to surveys are not appropriate. Contact WOODWEB for more information on initiating a survey.
  • Excessive forum participation by an individual upsets the balance of a healthy forum atmosphere. Individuals who excessively post responses containing marginal content will be considered repeat forum abusers.
  • Responses that initiate or support inappropriate and off-topic discussion of general politics detract from the professional woodworking focus of WOODWEB, and will be removed.
  • Participants are encouraged to use their real name when posting. Intentionally using another persons name is prohibited, and posts of this nature will be removed at WOODWEB's discretion.
  • Comments, questions, or criticisms regarding Forum policies should be directed to WOODWEB's Systems Administrator
    (return to top).

    Carefully review your message before clicking on the "Send Message" button - you will not be able to revise the message once it has been sent.

    You will be notified of responses to the message(s) you posted via email. Be sure to enter your email address correctly.

    WOODWEB's forums are a highly regarded resource for professional woodworkers. Messages and responses that are crafted in a professional and civil manner strengthen this resource. Messages that do not reflect a professional tone reduce the value of our forums.

    Messages are inappropriate when their content: is deemed libelous in nature or is based on rumor, fails to meet basic standards of decorum, contains blatant advertising or inappropriate emphasis on self promotion (return to top).

    Libel:   Posts which defame an individual or organization, or employ a tone which can be viewed as malicious in nature. Words, pictures, or cartoons which expose a person or organization to public hatred, shame, disgrace, or ridicule, or induce an ill opinion of a person or organization, are libelous.

    Improper Decorum:   Posts which are profane, inciting, disrespectful or uncivil in tone, or maliciously worded. This also includes the venting of unsubstantiated opinions. Such messages do little to illuminate a given topic, and often have the opposite effect. Constructive criticism is acceptable (return to top).

    Advertising:   The purpose of WOODWEB Forums is to provide answers, not an advertising venue. Companies participating in a Forum discussion should provide specific answers to posted questions. WOODWEB suggests that businesses include an appropriately crafted signature in order to identify their company. A well meaning post that seems to be on-topic but contains a product reference may do your business more harm than good in the Forum environment. Forum users may perceive your references to specific products as unsolicited advertising (spam) and consciously avoid your web site or services. A well-crafted signature is an appropriate way to advertise your services that will not offend potential customers. Signatures should be limited to 4-6 lines, and may contain information that identifies the type of business you're in, your URL and email address (return to top).

    Repeated Forum Abuse: Forum participants who repeatedly fail to follow WOODWEB's Forum Guidelines may encounter difficulty when attempting to post messages.

    There are often situations when the original message asks for opinions: "What is the best widget for my type of shop?". To a certain extent, the person posting the message is responsible for including specific questions within the message. An open ended question (like the one above) invites responses that may read as sales pitches. WOODWEB suggests that companies responding to such a question provide detailed and substantive replies rather than responses that read as a one-sided product promotion. It has been WOODWEB's experience that substantive responses are held in higher regard by our readers (return to top).

    The staff of WOODWEB assume no responsibility for the accuracy, content, or outcome of any posting transmitted at WOODWEB's Message Boards. Participants should undertake the use of machinery, materials and methods discussed at WOODWEB's Message Boards after considerate evaluation, and at their own risk. WOODWEB reserves the right to delete any messages it deems inappropriate. (return to top)

  • Forum Posting Help
    Your Name The name you enter in this field will be the name that appears with your post or response (return to form).
    Your Website Personal or business website links must point to the author's website. Inappropriate links will be removed without notice, and at WOODWEB's sole discretion. WOODWEB reserves the right to delete any messages with links it deems inappropriate. (return to form)
    E-Mail Address Your e-mail address will not be publicly viewable. Forum participants will be able to contact you using a contact link (included with your post) that is substituted for your actual address. You must include a valid email address in this field. (return to form)
    Subject Subject may be edited for length and clarity. Subject lines should provide an indication of the content of your post. (return to form)
    Thread Related Link and Image Guidelines Thread Related Links posted at WOODWEB's Forums and Exchanges should point to locations that provide supporting information for the topic being discussed in the current message thread. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related Link that directs visitors to an area with inappropriate content will be removed. WOODWEB reserves the right to delete any messages with links or images it deems inappropriate. (return to form)
    Thread Related File Uploads Thread Related Files posted at WOODWEB's Forums and Exchanges should provide supporting information for the topic being discussed in the current message thread. Video Files: acceptable video formats are: .MOV .AVI .WMV .MPEG .MPG .MP4 (Image Upload Tips)   If you encounter any difficulty when uploading video files, E-mail WOODWEB for assistance. The purpose of WOODWEB Forums is to provide answers, not to serve as an advertising venue. A Thread Related File that contains inappropriate content will be removed, and uploaded files that are not directly related to the message thread will be removed. WOODWEB reserves the right to delete any messages with links, files, or images it deems inappropriate. (return to form)
    Limtech Industries, Inc. Lamello