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Since I will be using a sander rather infrequently, I figured I'd save myself collecting more hardware by buying just a (portable) belt sander and using it for both serious sanding (areas on floors that are unreachable with a machine) and light-weight sanding (wood tabletops).

But for tables, I'm having a hard time getting a smooth finish, using 180-grit paper. Maybe 220-grit will make a big difference, but I doubt it.

Does either an orbit sander or a mouse sander give you more control when sanding a wood tabletop, to get a smoother finish? (I've applied linseed oil to seal, and am now applying polyurethane to finish).

Asked differently, is a belt sander just too much (unmanageable, takes too much too quickly, not random but leaves linear streaks, ..) to be used for finishing tabletops?

orbit sander

belt sander

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Your biggest problem is that handheld belt sanders are optimized for removing large amounts of material quickly. They only run at a single, fast speed and ergonomics of the thing contribute to digging in. Think how much more abuse your lawn would take being driven over by a car restrained by a chain around the rear bumper.

Floor standing machines, by contrast, can be much less aggressive. Thickness sanders are used to dimension wood for instruments. Wide belt sanders can put a finish sanding on just about anything.

That being said, unless there's an absolute ton of dust in the air I'm partial to hand sanding finishes (as opposed to the underlying wood). It doesn't really take any longer with practice, and it's less cumbersome when switching from the block to paper for curved surfaces. [Though once the table is large enough I'd switch to a machine.]

As far as the wood itself goes, I've always liked a half sheet orbital sander for large surfaces like tabletops. The extra size is a big improvement over the palm sander and you can go flush into corners with it. The quarter sheet palm sanders are probably a bit more convenient for most things though.

FYI the largest advantage of the round random orbital sander over the sheet ones historically is that the disks come with holes in them which allows you to connect it to dust collection. It still beats the hole punch guide newer sheet sanders that support dust collection subject you to. If you only work outdoors both are viable options.

  • Understood, but now I'm no longer sure what the handheld belt sander is useful for. I thought it would be a more efficient way to sand the edges in a room, after being done with the standing sander, but even there the belt sander leaves marks that remain visible after applying poly. – Calaf May 17 '18 at 10:33
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    A belt sander is good at taking a rough piece and working with the grain to get it ready for finish work. I have 2 bench belt Sanders 1 is a "strip" sander only 1 or 1-1/2" wide the second is 4" wide by 36 long these are great for prep work, yes I have 2 or 3 hand held belt Sanders but I rarely use these except removing finish & weathered surfaces from outdoor tables, benches and refinishing flooring. So they do have a use but not with the final sanding as I said in my answer. – Ed Beal May 17 '18 at 15:16
  • @Calaf - Prior to the mid seventies RO sanders weren't an option. If you own a planer and a RO, you'll basically use it for nothing. I use mine for things I don't want to abuse either of those with. – Mazura May 19 '18 at 1:17
  • @Mazura Interesting that you say that, because I'm now even more intrigued to figure out how an RO sander gets its randomness. But remaining practical, you're saying the belt sanders do not come handy even for the edges of floors of rooms? – Calaf May 19 '18 at 5:46
  • @Calaf - Edges are what my edger is for: a non-ROing circular sander. Which will leave marks on but the hardest of flooring that you have to clean up with a RO anyway. My RO has a switch to remove more stock (not sure how that works ;). w/o an edger I guess I would use a BS... and then a RO. Like Ed says, they're for stock or finish removal - not sanding per say; there's better options. – Mazura May 19 '18 at 15:01
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Because of the different motions, a belt sander could cause a deeper "line" where the edge of the belt hits the wood, since you can only go back and forth with it, certainly not optimal. With an orbital sander you would be moving it very quickly, in different directions and because of the way the pad moves as well, you would not be "eating" into the wood as quickly or in a line, as mentioned before, this is certainly the way to go.

  • That's kind of the answer I would have given, and that I somewhat allude to. But do you know this to be the case? For example, have you tried a belt sander and given up, or have you read an expert opinion that says it can't be done with a belt sander, not even with gentle swaying to avoid the straight lines? – Calaf May 16 '18 at 18:02
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    Yes. I have not and would not try to use a belt sander for your application. Can it be done? It can probably be done with a lot more time wasted and a headache. – riseagainst May 16 '18 at 18:31
  • @Calaf I'm sure it could be done with a belt sander, but it would be far more likely to result in marring and marks that you'd need to sand off. I've tried using a belt sander for large surface areas and even while being careful, managed to gouge the wood a bit and had to revisit the sanding multiple times to fix it. I've never had that issue with random orbital sanders. – UnhandledExcepSean May 16 '18 at 19:45
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I would NEVER use a belt sander for finish work especially with polyurethane. Can it be done , not with 220 grit and possibly not even with 400 grit. Belt Sanders rip a line with each grain of the paper trying to blend a rough wood to prepare for finish is tough enough but I would say just hand sand the poly before using a belt sander or you will be starting over in my opinion.

  • OK, understood. But the randomness in the "random" orbital sander is still better than hand sanding; is that right? So it's not a question here of some elbow grease producing a superior result; it's actually desirable to use the randomness to ensure that there are no streaks, generated either from a belt sander or from one's own hand motions. – Calaf May 16 '18 at 23:49
  • When doing poly the trick is to lightly abraid or scratch the surface a random pattern is best in my opinion but I have done work where hand sanding was the only way (round stock) and to tell the truth there was no difference other than the time it takes. I was taught to use figure 8 overlapping patterns and with some practice and a fine grit you can do true craftsman quality work with just a little practice. Go finer to start 600 will take longer but would be hard to mess it up or cut through all the poly. – Ed Beal May 17 '18 at 0:07
  • @Calaf The human hand actually has decent randomness, if you let it. If you lock it into a groove, back and forth, there will be streaking, but if you do a more complex pattern which lets your joints move more, like the figure 8's Ed mentioned, the results are great. An interesting factoid: when polishing telescope mirrors (which must be ground to 50nm from perfect to get decent results), the human hand is preferred to all known tools. No tool generates the smooth randomness for mirror making as well as the human hand does. – Cort Ammon - Reinstate Monica May 18 '18 at 19:14
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YES!

In simple terms, the "grit" with the belt sander moves in a single direction at a high rate of speed. That's good when you're trying to remove a lot of wood, but not so good when you want a nice smooth surface for finishing. The uniformity of the resulting pattern is easy for the eye to pick out and sometimes will be made more prominent by stains and polyurethane finishes, etc.

On the other hand, the random orbital sander moves the "grit" in random directions without leaving a recognizable pattern or gouges in the wood. It also moves more slowly allowing for greater precision and control. The resulting surface is much more suited to finish work.

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