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A lot of sandpaper multi-grit packs suggest that you should work your way through all of the grits from coarsest to smoothest on a job.

The way I see it, it seems like only two are necessary - the coarsest to remove any excess material from what you're working on, and the smoothest to smooth out the material once you're done. Is anything in-between really necessary?

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  • 4
    This might be a better fit at Woodworking and there are likely a lot of questions on sanding there.
    – FreeMan
    Sep 1, 2022 at 12:29
  • Only if the two grits are adjacent to each other.
    – DKNguyen
    Sep 1, 2022 at 15:15
  • 9
    That's like saying you only need two golf clubs, one for long shots and one for short shots. Sep 1, 2022 at 15:54
  • If you can't tee off with a putter, or putt with a driver, can you really call yourself a golfer? :)
    – chepner
    Sep 1, 2022 at 21:59
  • 2
    @DKNguyen as long as the club is sufficiently private.
    – mustaccio
    Sep 2, 2022 at 1:11

3 Answers 3

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We use a progression for grits to quickly and efficiently sand things.

Each successive grit is used only long enough to remove the scratches left by the coarser grit before.

     vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvfine grit
     / smooth  \         / smooth   \
    /           \       /            \    
   /             \     /              \
  /               \   /                \
 /  Coarse grit    \ /  scratch bottom  \

If you "skip grits" you'll waste a lot of time, or still have deep scratches from the coarsest grit that your finest grit hasn't gotten to the bottom of when you give up and put finish on.

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    Fully agree, but with a caveat. If there's 60, 80, 100, 120, 150, 220 & 300 in the pack, there's no real need to use each and every one. Depending on how smooth the surface already is, one could start at 100 then move to 150 and be done. If it's a really rough surface, 60 or 80 might be the right starting point, then one could potentially skip to 120 with good sanding technique. i.e. there is no "one size fits all" answer. 220 and 300 are rarely needed.
    – FreeMan
    Sep 1, 2022 at 13:27
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    I think OP's belief that two is enough is often the case based on having a reasonable starting condition and no desire to produce a masterpiece. I use two grits for most jobs, 3 for some. In some cases for wood I'll use 60 then 120 on unfinished wood then 220 between coats of finish and 400 before the last coat. It depends on the graininess and damage to the material I'm beginning with and the type of finish. I've never done high gloss automotive type finishes but those people get into much finer grits and pastes.
    – jay613
    Sep 1, 2022 at 15:08
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    @jay613 OP didn't just say two grits. OP said the coarsest and the smoothest in the package.
    – DKNguyen
    Sep 1, 2022 at 15:17
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    "If that's your thinking, simplify even further and just use the finest grit to do everything" No, because the first part of the job is removal of excess material, for example sanding down a sticking door. I'm clearly not going to do that job with the finest grit, that's insanity.
    – Chris A
    Sep 2, 2022 at 13:05
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    @ChrisA The whole job is the removal of excess material. Removing the excess material between the deep scratches of the coarsest grit by using the finest grit is, therefore, also insane.
    – Ecnerwal
    Sep 2, 2022 at 13:11
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Do you want a professional result or a "meh" result?

You didn't specify grit so go ahead and try going from a 24-grit to 200.

Going from something sensible like 60 grit to a 200 grit will basically ensure that you'll have strands which simply lay back into where they came from. These strands will swell and stick upright when you go to apply stain or polyurethane.

If you're just color painting with a brush then you can do 60-grit and call it a day. If you're painting with a foam roller then at least go for 120-grit.

Anyways, the method used and time spent hinges on whether you expect a great result.

2

It depends on the job.

One course grit will be fine if you just want to remove a lump or ridge.

Course grits are use to remove a lot of material fast. Want to remove 1/2 inch go with 60 or smaller number. Job should be okay if going to slap a few coats of paint on.

The finer grit you use will remove less material in the same time, but leave a smoother surface.

If wanting to make a very smooth surface, like a very fine dinning table, you will want to use a few grit numbers from course to very fine, might not need to use every number in the pack, can maybe skip a few. Will depend on the surface you want, just smooth or glass smooth.

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    agreed. but there is an old joke among woodworkers: "when are you done sanding? the answer is never"! If doing a fine piece of furniture I'll sand down to 400. But even so, after applying the first layer of finish (assuming it's not oil), it almost always raises the grain which requires a very light sanding between coats. This is esp. true with water based finishes. The second coat is usually very smooth and if you want good durability (like a kitchen table) another very light sanding and a 3rd coat will get 'er done. BTW, I use pre-cat lacquer, probably shortened my life span. Sep 1, 2022 at 14:45
  • Want to remove 1/2 inch? I think I'd skip the sandpaper and go with a chisel or plane.
    – Glen Yates
    Sep 8, 2022 at 19:20

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