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Thread: sanders and sand paper

  1. #1

    sanders and sand paper

    Ok. We dont need to do a brand war, but I am really strugling with my finish sanding. I have 1/4 sheet vibrating sanders, and I use the aluminum oxide sticky back. I am doing a bunch of pine pieces and I run to 220 grit. I use thinner to raise the grain in between grits and I keep getting rogue sander swirls. Please help. It is driving me crazy and costing me money.
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  2. #2
    You are moving your sander too fast. Think in terms of "feed rate". You need to slow that down. Also, if your pad is worn or if it's soft and you bear down too hard on the sander, the heads of the screws that hold the pad on can "telegraph" through the paper and mar the wood, especially with finer (thinner) papers. Finally, you might want to do your final sanding "by hand" with the grain to get out any stray marks left by the RO sander.
    Last edited by David DeCristoforo; 01-20-2009 at 9:12 PM.
    David DeCristoforo

  3. #3
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    David hit all the points I might have responded with except that I prefer a ROS to the 1/4 sheet for "just before finish" sanding. I hand sand as my 'finish' sanding step. Those are pretty definite markings. In addition to feed rate ( I use about 1" per second with my ROS) I let the weight of the sander do the work, I just guide it. Also, the quality of good sandpaper is woefully overlooked.
    "A hen is only an egg's way of making another egg".


    – Samuel Butler

  4. #4
    Ok, so slowing down, I will check the pad, how about paper? Can you tell by the pic that it is just a speed issue, or is it possible that there are other factors? In addition, I have a tool for cleaning my disc sanders a belt sanders, but it doesnt work on the palm sander. Any trick to clean the paper and extend the life? One last thing, what is ROS?

  5. #5
    Random Orbit Sander

  6. #6
    I suggest you switch to a random orbit sander. I have both Porter Cable and Bosch random orbit sanders and both work well. I also have a 1/4 sheet Makita sander and it nearly always leaves swirl marks so it gets little use.

    I do nearly all my work on hard maple that is stained. Hard maple is very unforgiving. Any swirl marks or missed spots show up immediately. I have developed a procedure that works for me 100% of the time to eliminate defects. I tried just about every procedure I could think of over the years and find the procedure below always yields defect free surfaces for me.

    1. I use a random orbit sander hooked up to a vacuum to work dust free. The sander also cuts more aggressively when the dust is vacuumed away as I work.
    2. I put random pencil marks on the wood and sand until the pencil marks are gone. This assures that I don't miss spots. The pencil marks are reapplied between grits.
    3. I never skip grits. I do 80 grit, 100 grit, 120 grit and 150 grit. I don't find it helpul to go beyond 150 grit. I start with 80 grit even though I put most pieces through my Performax drum sander with 120 grit on it. Starting with 80 grit assures that I get all the 120 grit belt marks off. I have sanded up to 220 grit and have seen no difference in the finish. I don't hand sand after using the random orbit sander as I found this often produces scratches that show up after staining.
    4. In between grits, I hold the piece up to a light and make sure the sanding is thorough. Under an angled light, the appearance of a well sanded surface is obvious.
    5. I spend a lot of time on the end grain. I use 80-100-120-150-180-220-320-400 grit hand sanding the end grain with pencil marks in between. I don't want the end grain to over absorb stain so I make sure the end grain is over sanded to seal it. Ideally, the end grain should be almost shiny when the sanding process is right. I also put a coat of shellac on the end grain before staining so it is further sealed to prevent over absorbtion of stain. It really doesn't take that long to go through all the grits.

    Though many sandpapers can yield results. I like Mirka Gold the best. It cuts well, lasts a long time and resists clogging well.

    Good luck with your sanding.

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