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Thread: losing my mind over sanding swirls

  1. #16
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    I'm not a big hand plane woodworker but I would guess that, if you get a smooth level surface with a hand-plane, starting with 100 grit sandpaper is not necessary. I would use 80 or 100 grit only if I were trying get rid of imperfections or slight glue joint inconsistencies. Handplaning should get rid of those. Using 100 grit at that point would be like sanding veneered plywood with grits coarser than 120 since that is what most ply is sanded to from the factory. I would probably start with 220 grit or even 320. If you're staining the surface then you would run into problems of absorption of the stain but if you're doing a natural finish, then the smoother the better.

    I think the suggestion of turning down the suction of the vac is excellent. I use Festool vacs and find that on a large flat surface the vac can be turned down to its lowest setting and the dust will still be sucked up.

    Maybe you're moving the sander too slow. After all the surface is already smooth. As I said I'm not a hand plane guy. Since I began using Festool sanders and vacs I almost never get swirls. If I do, I know I'm unknowingly doing something wrong.

  2. #17
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    This is wonderful, thank you everyone!


    Jon E. - about moving too slow... This was my attempt to remedy that I thought I was going too fast in the past, so perhaps the happy medium is the ticket. Also, very glad to hear that my existing sanders ought to be fine - I had invested in those after a fair amount of reading and am happy to hear they aren't the likely issue.

    Jim B. and Randy - Thanks for confirming idea on the vacuum suction. I think I saw a simple "bleeder" design that Glenn B. posted awhile back and will try that.

    Bob M. - Good idea on the mineral spirits after each grit... Will do that on my next project.

    Patrick / Steve - great idea on the pencil marks... I do that when planing and can see the logic here too


    I'll report back on my next project soon! Thanks again!!
    - Bob R.
    Collegeville PA (30 minutes west of Philly)

  3. #18
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    I hope I didn't miss it, but how much pressure are you pushing down on the sander? Your hand should only move the sander, not pushing down on it. You should not hear the sander change rpm when doing the work. Next, how often do you change abrasive? Use sandpaper like you stole it, replace it often! I use two grits on a belt sander before moving to a random orbit. It's not easy to keep a flat surface with a round disc. I stop sanding with 220 before finishing and use 320 between coats of finish.

  4. #19
    The only thing I can think of that hasn't been mentioned is wetting the surface then repeating the final grit.

  5. #20
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    My random orbit and orbital sanding starts at 120. Pryor to 120 all sanding is done with the grain. Bigger RO sanders leave bigger swirls.
    Best Regards, Maurice

  6. #21
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    I also start at 120 grit. Personally, I think starting with 100 grit risks scratches that the higher grits won't work out, as has been said above.

    Almost all of my sanding is done with my Festool 150/3. So not changing sanders. Suction turned down most of the way. Start against the grain, then diagonal, then with the grain. Seems to work and not leave swirls. I fortunately haven't faced this issue.
    - After I ask a stranger if I can pet their dog and they say yes, I like to respond, "I'll keep that in mind" and walk off
    - It's above my pay grade. Mongo only pawn in game of life.

  7. #22
    Experiment with different movement speeds as mentioned a couple times. A "raking" light (low angle) should highlight swirl marks There's nothing to gain moving up to the third grit if swirl marks from the first grit still present.

  8. #23
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    Swirls from fresh 100 git on a R.O. go deep. It is very difficult to get rid of them. I am sure they can be measured, A few ten thousands of an inch... they do not go away when followed by finer grits.
    Last edited by Maurice Mcmurry; 08-04-2022 at 11:13 PM.
    Best Regards, Maurice

  9. #24
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  10. #25
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    No one has mentioned card scrapers. After a couple quick passes with a No. 4-5 Plane, try using a card scraper. You might find that you don't need sandpaper below 150g.
    Regards,

    Tom

  11. #26
    My main concern:
    Once that coarse (36-80)grain is implanted in the pores, it can easily camp there, only to be dislodged during later courses. Maybe vacuuming after each course will grab every last spec - maybe washing down with mineral spirits would help.
    IMHO: Don't go that coarse to begin with.

    Unless I'm grinding finish off the floor of a deck outdoors, I never reach for anything less than 120 grit for the R/O.
    Max out at 150 - 180.

    Secondary consideration:
    May have missed it, but I've seen little mention of hand sanding. Final sand with the grain using a large block (EG:3"x14") and hand pads for a final dressing before finishing.
    I've read other's advice to do this with 1 grit higher than last grit run on the R/O, though I've always done well with a final R/O at 180 and matching it for the hand sanding.
    Incidentally, that block and a series of pencil lines can help spot/conquer high spots in the early stages, much like a hand plane, if an inordinate amount of levelling is needed and you're not adept with the hand tools.

    Swirls suck. Don't let them suck the enjoyment out of your woodworking.

    jeff

  12. #27
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    Quote Originally Posted by Jeff Roltgen View Post
    My main concern:
    Once that coarse (36-80)grain is implanted in the pores, it can easily camp there, only to be dislodged during later courses. Maybe vacuuming after each course will grab every last spec - maybe washing down with mineral spirits would help.
    IMHO: Don't go that coarse to begin with.


    Unless I'm grinding finish off the floor of a deck outdoors, I never reach for anything less than 120 grit for the R/O.
    Max out at 150 - 180.

    Secondary consideration:
    May have missed it, but I've seen little mention of hand sanding. Final sand with the grain using a large block (EG:3"x14") and hand pads for a final dressing before finishing.
    I've read other's advice to do this with 1 grit higher than last grit run on the R/O, though I've always done well with a final R/O at 180 and matching it for the hand sanding.
    Incidentally, that block and a series of pencil lines can help spot/conquer high spots in the early stages, much like a hand plane, if an inordinate amount of levelling is needed and you're not adept with the hand tools.

    Swirls suck. Don't let them suck the enjoyment out of your woodworking.

    jeff

    I have routinely used 60 grit (and sometimes 36 grit) on tabletops that have a lot of cleanup required to get uniformly flat. I use a hand plane to take off the worst of it, but once I'm down to fingernail catch close I prefer to sand because it eliminates the chance for tearout. I've never had a problem with coarse grit getting lodged in the pores. The tabletop I showed above was red oak and Sapele. If anything is going to capture loose grit it's red oak. It just doesn't happen. When I did that tabletop I didn't even have access to a shop vac. I just brushed it off between grits, then wiped it with my bare hand. You will feel large grains of grit with your hand. Any little shards that are stuck in the grain that you can't feel aren't going to be a problem with the next grit. I'm not suggesting what I do is the right way, only that it works and is more efficient for me with no worry of tearout.

    John

  13. #28
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    When you say you get swirls, is it a few like seen in the link? I will get these once the paper starts to were. If you are starting with new paper and sanding tables you may get to a point where the paper wears out before the end of the grit your on. If you were sanding coasters id be scratching my head. I would visually inspect each grit sanded. If they have appeared you will have to drop back to get rid of them. Dont progress you will get even more frustrated. I would suggest Mirka Abranet It lasts a long time and they are very consistant.
    If you are using hand tools to smooth the joints/glue starting at 120,180,240(I use the dont progress by more than 1/2 current grit rule) with the abranet should be sufficient.


    Found this while I was looking for a picture of swirls
    https://www.abrasiveboss.com/blogs/i...n-wood-sanding

  14. #29
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    Did the videos you watched include the sanding video from Stumpy Nubs? I recently watched his sanding video and multiple times he talked about avoiding pigtails.

    In my experience, I tend to get pigtails if I'm not keeping the sander flat.

  15. #30
    I'm not suggesting what I do is the right way, only that it works and is more efficient for me with no worry of tearout.
    Who hasn't taken "one last pass" with a plane only to muck it up?

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