Use for a finish sander?

What Leon, said.

Again, what Leon said, except add to that, "breaking"/easing the edges has a valid purpose in finishing, other than mentioned by posters thus far, such as for feel, appearance, and protection of edges from breaks and splintering on impact.

Sprayed and/or painted top coat finishes have a tendency to build up on sharp edges, which can often result in areas that may flake and/or show an unevenness, sometimes even in shade/color.

Reply to
Swingman
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Actually I do ease inside edges, If I can touch the edge I ease it no matter where it is. I simply don't ease edges before assembly as some of those edges will no longer be exposed. I don't ease the edge of the end of a rail where it joins a stile.

This is as I mentioned where all edges including those in the joint have a chamfer or other profile on all edges of the rails and stiles.

Reply to
Leon

Since I seem to have triggered this discussion, I'll chime in.

I agree with Mike. I've never had a problem with cross grain scratches using my ROS. Sure, you can see scratches in coarser grits, but they're orbital, not directional. If Leon is seeing scratches most likely he's either not going to a fine enough grit, he's bearing down too hard, or he has an orbital sander, not a *random* orbital sander.

I can't state that there's no ROS that will do what Leon's does, but I can state that mine (an old Bosch) doesn't.

Can the mechanism in an ROS fail in such a way as to eliminate the randomness?

Reply to
Larry Blanchard

OK, I'm taking sides here. ;)

My experience in that regard more closely matches Leon's.

IME, ROS sanding scratches do show up on crossgrain (proportionate to the coarseness of the grit) much more than on long grain when using a ROS across a crossgrain joint, like a rail and stile, even with a top quality random orbit sander.

Unfinished, you might never see them, but they have a tendency to become much more evident under a stain and topcoat.

Leon uses a 5" Festool ROS, IIRC ... and one look, up close and personal, at anything he builds and finishes will tell you, without equivocation, that he indeed he is a master at using it. ;)

Again IME, and because there are a myriad of reasons where you do not want to sand past a certain grit, heeding Leon's advice regarding following grain direction when using a ROS, may well save a project you just thought that, by using a ROS without regard to grain, there would be no problems with sanding marks showing up after a stain and topcoat was applied.

YMMV ...

Reply to
Swingman

As often happens, I don't see a clear answer. Still, I usually learn something. Here's why I asked:

For those of you who have forgotten, or figure I MUST have moved on to a new project by now, I'm building two of these:

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(plus shelves and a top, of course)

I've made essentially no progress at all since the dry fit pictured in the photo. (family obligations) As you can see, the project is composed practically entirely of face-frame-like components. I think I did a fair job of lining up the dowel holes that will hold it all together, but especially after sanding all of the pieces individually, I'm sure the joints on the ladder sides won't be exactly flat.

I had considered easing the edges on the parts (including the ends of the "rungs") before assembly, leaving an deliberate line between the rungs and uprights. But the fit was pretty good in the dry fit, leading me to wonder if I could sand over the joints somehow to fix any imperfections.

I would normally have guessed the answer was "no". But Larry Blanchard's suggested otherwise. So do you guys simply have sufficient accuracy that this never comes up? Or is there some method you use to sand the joints flat?

Reply to
Greg Guarino

It has nothing to do with randomness, nor orbital for that matter. It has to do with the movement of the sander itself, not the motion generated by the sander.

Reply to
dadiOH

I always do finish sanding afrer assembly. My only method is to use a

1/2 sheet - sometimes - 1/4 sheet depending upon area - which gets joints nice and even. I don't use my ROS for two reasons...1. I don't like them and, 2. the 1/2 sheet does a better job IME.

In the case of your "ladders". I might well have cut a "small V" quirk; it could save a lot of work and could look good.

Reply to
dadiOH

"Larry Blanchard" wrote

Most definitely. You would notice it, because the normally tame sander turns into a grinding disk instead of a ROS.

There is a ball bearing that can tie up due to the fine dust, but a high quality sander has a good enough seal that it is unlikely to seize. That being said, I have seen it happen.

Reply to
Morgans

Having that deliberate line is often done to hide joinery imperfections; it can also be a deliberate design feature; and it can certainly serve both purposes at the same time.

The decision is entirely up to you, so keep'em guessing. ;)

I personally have rarely used that particular method/device to hide inaccurate joinery in face frames ... can't remember the last time.

The issue where it would be necessary is mostly one of project parts not being cut or milled perfectly square/at right angles.

By insuring your stock is prepared with square edges during milling, ripping, and crosscutting, and by batch cutting ALL parts, you can pretty well discount that being a problem.

That notwithstanding, that does not preclude the occasional need to sand some joints to insure their adjoining exposed faces are level with each other ... a not uncommon occurrence when gluing up parts using any joinery; often a byproduct of clamping issues, like slight slipping under pressure.

Depending upon the severity, most of these can be taken care with a finish sander, or the "aggressive" setting on a ROS if need be, and you have one that will do that.

However, when installing a 15' run of face frame, base or wall cabinets to each other, a ROS (preferably one with an "aggressive" setting, like the Festool 5 and 6" Rotex sanders) is often essential in getting an evenly matching surface between adjacent cabinets so the doors and drawer fronts are in the same plane to those in adjacent cabinets.

Many folks who own one, as well as just about every cabinet shop that specializes in items that use that type joinery, will routinely run all their doors, face frames, door fronts, and anything with that similar type joinery, through a large drum sander as a matter of course.

IOW, it's not like its an uncommon issue.

Reply to
Swingman

I have finish sanders and a single-setting ROS (DeWalt). But what I'm asking is, do I sand right over the joint? Grits?

Reply to
Greg Guarino

I'm aware of this. But it has often made me wonder how the cross-grain sanding doesn't produce bad effects.

Reply to
Greg Guarino

Not the final sanding...

Reply to
Swingman

Can't advise you on your specifics because every situation is different. But, I can tell you what I usually do:

Almost always run through 100, 120, 150 with a finish sander, with the grain on real wood; I generally start with 120 or 150 with plywood.

Use the ROS, on the high side only of problem area, with the coarser grits as necessary (run through 60?, 80 and 100) for problem areas. Switch to a finish sander, with the grain, and with 100 (over above sanding), 120, 150.

Then, depending upon the project, 220 by hand to lightly sand the faces and break edges.

On bath and kitchen cabinet wood that will be stained/painted I usually go through 100, 120 and 150; stop at 150 and break the edges, by hand, with that.

On stain grade veneered plywood parts, I finish sand lightly at 120, 150.

In all case for the final three grits (100, 120, 150), I use a finish sander, with the grain only; and sand up to, but do not sand across, the joint in either direction.

YMMV ...

Reply to
Swingman

FWIW I used a PC Right angle ROS starting in the late 80's and used it until going to the Rotex 5~6 years ago.

Revisiting the ROS action, yes it is a random action but if you are going cross grain you are still moving the cutting edges of the grit across the grain. Yes the ROS is better than a regular "non random" orbit sander but I can't get away with what I see if I get up close and personal. I very very very seldom have ever used a ROS as the last step for sanding regardless of grit.

Now having said that I too have used a Bosch ROS. By comparison it was much less aggressive and beyond noticeably slower than both the PC and the Rotex in ROS mode so perhaps some ROS sanders don't display that scratch pattern but IMHO the whole purpose to use a ROS over a finish sander is to speed up the sanding process.

Reply to
Leon

The drum sander is not the final pass. I have a drum sander and use a relatively coarse grit. I use the drum sander to make everything flat and smooth. I follow up with a ROS and then a finish sander. Keep in mind that the drum sander normally removes the problem areas so the ROS and finish sanders are simply smoothing out the scratch pattern produced by the drum sander.

Reply to
Leon

"Greg Guarino" wrote

Belt sand any really bad high spots with 120, go to 120 with ROS and sand over the whole thing, joints and all, then 150 if painted, and 220 if stained. I threw away my finish sanders. It always seemed I got a piece of sandpaper that had some larger rocks in them, then it mad swirls all in my piece. Not a problem with the ROS. Also, speed is key. If you have a single speed, go down and get a ceiling fan motor speed controller, and put it in a box with a male and female plug to run the sander. Not ideal, but it works.

That is what I do, anyway. YMMV.

Reply to
Morgans

And right at the tee-joint line ... what? Do you try to just barely touch the edge? I'm trying to get an idea of how big an issue this is.

I'm thinking I could machine sand as carefully as possible up to the line on the "bottom" piece of the "T", inevitably going over a little. But on the "top" piece, I could hand-sand without going over the edge at all for the last grit, especially if I were to make a custom sanding block with a "stop".

Like this:

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But I have a feeling you guys don't do anything like that.

Reply to
Greg Guarino

If you are talking about the butt joint where like a rail and stile join, I sand that with ROS usually down to 150 grit and pay no attention to grain. Then the transition or joint is smooth I switch to my finish sander and the same 150 grit and will try to only move the sander in the direction of the grain. I first run the sander along the piece that runs into the other. If I go too far, into the mating board with the grain running 90 degrees to the piece I am sanding, I work that out when I sand the other piece. It is easier sanding in this order than sanding in reverse to that order. Then I do the same with 180 grit and the finish sander. Because finish sanders typically use rectangular pieces of sand paper it is easier to control exactly what you are sanding.

I have always looked at the round disk ROS sander as one to remove bulk but with much more fineness than a belt sander. For the last grits I almost always use a finish sander so that I can have more control with direction. About the only time I will finish sand with a ROS is when sanding large non-enclosed panels, cabinet sides or tops. ROS's can't get into inside corners and are tough to hold flat on the edge surface of a face frame, doors, drawers, anything narrow..

Reply to
Leon

How do you sand inside corners with a round disk?

It always seemed I got a

This can easily happen with any sander if you are not using a vac to capture dust and or do not wipe down the surface between grits. OR if you are using marginal quality sand paper.

Not a problem with the ROS. Also, speed is

Reply to
Leon

Exactly what I was attempting to explain in the previous reply. BUT if you have a small finish sander it is easily done with that instead of using brute force. ;~)

That is a little over kill. LOL BUT it should work. You don't quite have to be that anal, sanding should be FUN! ;~)

If you fold the paper into the corner of the block it will also ease the outside edge and sand the outer edge at the same time. BUT unless executed perfectly it could round the outer edge more than you want. Better to use two pieces, one for the outer edge surface short of the corner and one for the surface short of the corner, come back and get the corner.

Free hand sanding with a block of wood or finish sander should allow you to get close enough with out going over on the pieces that butt. Once yu get into the finer grits the stray scratches tend to be overshadowed by that line at the joint where the two pieces meet.

One other thing, I buy foam backed 4x4 sheets of finish grit sand paper. The makes for great hand sanding with out a block, the foam prevents you fingers from slipping and is great for quickly easing over edges in tight spots and corners. I typically use Mirka brand found at Woodcraft.

Reply to
Leon

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