I had an older model of the Porter Cable 5" random orbit sander that
finally bit the dust a year of so ago. Great sander, never left
marks on anything. Since then, I have bought and cursed at the
Ridgid, DeWalt, and Porter Cable sanders for leaving swirl marks on
pieces. Very faint on bare wood, but clearly visible when I apply
stain or other finish to the piece. Anyone have any ideas on how to
fix my sanders to prevent this? Or is it back to the old 1/4 sheet
sanders for 180 and 220 final sandings??
Start the sander above the work and slowly lower it onto the
work, then lift it off while it is still running. Do not press down
on it at all, the weight of the sander is sufficient. Move it
very slowly and steadily over the wood, do not stroke the
wood with the sander. Clean the paper frequently using
one of those gum rubber blocks. Don't skip any grits
on your way down and finish with a finer grit than you
have been using. Finish with light hand-sanding in the
direction of the grain using a sanding block and paper
one step up from the last stage of ROS sanding.
Or, for softwoods,
don't sand at all, use a #3 or #4 smoothing plane,
or a Knight hand-made wooden bodied smoother.
Or, for hardwoods,
don't sand at all, use a smoothing plane and
follow with a cabinet scraper if need be.
Or, (so I've been told) for a very hard wood like
ebony or rosewood follow the cabinet scraper
with hand sanding starting with 400 grit, and
keep going down in grits until the unfinished
wood is glossy. You can get paper down to
2000 grit at auto parts stores and can get
white corundum paper by mail order.
Sanding is a PIA. Planing and scraping is a joy,
at least until your thumbs get sore. Then you'll
start hunting for scraper planes.
Another vote for Scraping.
For flat cut surfaces, use better quality saw blades with dampeners. You
won't need to sand or scrape sawn surfaces after cutting. Items sell for >
$1000, never a touch of sandpaper and look better than sanded ever can.
(glossier, like scraping results)
Something else to try for general sanding, YMMV, lightly mist (not wet)
the work first to raise the grain, sand, then allow to fully dry.
Use suction during sanding, hook up a shopvac/dust collector to the
sander, not just a dust bag, to the dust port of the orbital sander.
Also I use an Oil-less (airbrush) air compressor to remove dust from work
and sanding pad. Not too much air pressure on the work or you'll be
A word of warning about that technique, older PC ROS sanders will dig a
divot in the surface almost instantly with that approach. Those old PC
sanders had no brake and would go into spin mode rather than random.
Awh, you just have not gotten to use a really good sander yet. ;~)
Planing and scraping is a joy,
Every sander leaves some kind of marks. With a ROS the thing is to
not let any swirls from the coarse grits slip through to the end, or
introduce new ones by some foreign matter getting into the works, so
that when you are done you just have uniform very fine swirls. Then a
light hand sanding is all you need.
Your old ROS probably did the same thing, you've just gotten better
and are looking harder at your work and expecting more. This is a
While the advice is generally good and certainly not letting large grit
carry over is mandatory, I'll agree w/ marc that I've not had problems
w/ old P-C's leaving detectable swirl on pieces even after
I can't comment on new P-C's or other varieties as I only have old P-C's.
I would expect that from any and would tend to put blame on paper and
final grit more than the sander itself, but again I've none others to
$0.02, imo, ymmv, etc., etc., etc., ...
The joy of reading a concise, level-headed reply.
Add to that, Leon's suggestion to blow off the grit from the previous
sand-paper, and you WILL get results.
Do not skip grades.
In the final stages, look for good dust removal and minimal pressure
on the sander.
Keep your paper fresh and your target clean.
*now I'm putting on some mittens so I won't be tempted type and extoll
the virtues of a Rotex sander..*
I still go to my old Speed block orbital for the next to final sanding.
Final, after a setup with water, is always by hand. Everything said in the
thread is true. Clean between and keep things flat without pressing. But
it's better to go with a small-orbit orbital, versus Randomfor the last, in
BTW, there are so many grits of paper out there that the phrase "don't skip
a grit" is even more meaningless than usual where start and end are
unspecified. Don't make big jumps in number or expect to sand longer.
Also, make sure you're in the same system, or you'll wonder why the P400
doesn't do any better than CAMI 320.
Yeah I have not yet parted or retired my Sped Bloc. It is still relative
new at 2 years old It replaced a Sped Bloc that lasted 18 years. But darn
it puts up a cloud of dust. I wonder if the Festool Finish sander is as
It'd be hard to beat this little thing:
When you buy the vacuum attachment, and attach it to a Fein II or
CT22...NO dust.. hell, the sander sticks to the surface... I can't
imagine The Green/Black Boys doing a better job......but then again, I
have made that error in judgement before...
I got my little Bosch for 49 dollars, IIRC.. and just love it. I Get
out my hole-punch set and whack away and make a stack of 6-hole 1/4
sheets sandpapers. Even the dust collection that comes with it is
quite effective...but just for a little while.
To change the paper is just a snap.. easiest ever.
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