Quoted from ForceFlow:I went through the process of sanding it down again. It still left me with fine scratches in the metal in the direction that I was sanding.
Sandpaper is graded to remove the scratches from the last grade.
If you sand with 80 and then move up to 120, you are not done with the 120 phase until all the 80 scratches are gone.
If you leave any 80 scratches, then move up to 220, you are wasting your time, because 220 can't remove 80 scratches.
Try this experiment on a scrap playfield bracket:
Sand north to south with 120. Don't press too hard, just let the paper do the work.
Now sand with 220 but only sand east to west. See how when the final 120 scratch is gone you are "done" with the 220? See the uniform surface when the whole area is 220ed?
Change the direction of your sanding back to north and south, with each grade change, change sanding direction.
Now sand out all the 220 scratches with 400, then move to 600, then move to wet 800, 1000, 1200, 1500, 2000 and finally 2500. There is again a uniform look when all the previous grade's scratches are gone.
Now when you finish with the 2500 grit, on a buffing wheel, hit it with Green Compound.
You now have a mirror finish that looks like chrome.
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You will be amazed at the results, but better than that, the above exercise will etch into your mind the importance of not leaving any scratches from the previous sandpaper grade. If you rush or skip a step, you get to go back a step.
Sana'a
