We spend a lot of time and money sanding. We have all kinds of machines. The goal usually is to get the piece flat and scratch free. Sanding with the grain is usually the best way to avoid the appearance of scratches.
Why hasn't somebody come up with a hand held sander that sands in a straight line?
I have several Random Orbital sanders. We all know they will leave curly swirl marks.
I have belt sanders, both portable and stationary. The portable one will leave gouges all over a table top. Snake trails.
I have a Performax and a big brother version from Grizzly with two drums and a 5hp motor. Not good on things like table legs.
A friend has a huge 36" industrial belt sander and a belt sander you can put a table top in and press the belt down on it. Ancient tech. That one comes close except that it is enormous. Must be 8' long and three feet wide.
Anyone tried a Sand Flee or whatever they call it? In that case you have to apply the wood to the tool.
Why isn't there a version of a rectangular ROS that moves in a straight line and does not leave swirls? Or a belt sander with maybe the edges of the belt rolled up to not leave snake trails?
.....lack of sanding equipment but your lack of the right equipment and/or knowledge of how to use it. All ROS sanders in experienced hands do not leave swirly marks. Ditto belt sanders. I don't have any of the problems you describe. I once did but I overcame these issues with the right equipment and experience using it. These machines are the way they are because the way they are is best. There isn't the machine of your dreams because it would be vastly inferior to what there is.
There isn't a short cut to a professional looking finish. My finishes always have a significant component of hand sanding, sometimes all hand sanding, and sometimes belt, ROS and hand. But the better I become at assembling panels the less I use the belt sander.
That said, I regard the belt sander the most difficult tool to learn to use that I have in the shop.
The PC Detail sander (with profiles) is an in-line sander.
You'll finds straight line sander(s) in the auto body tool store
If you have an appropriate Ryobi or P-C belter, you can get a sanding frame to match your tool that will prevent those "snake lines" and digs you decry. I have the Ryobi BE-321 in-line (rather than side-winder) belt and use it in a sanding frame. The frame is finely adjustable such that I can remove old finish on a table top yet take very little wood, and have "0" cross-grain scratches if I'm careful. Here is what it looks like:
It's attached to my shoulder and powered by steak and potatoes. One end is a quick change adapter which holds a variety of sanding implements such as soft or hard blocks, some with sandpaper glued on.
When I want to sand with shop power I use a ROS. Could it be the swirly scratches you see are due to too much pressure or perhaps rushing with finer grits? There is also the occasional issue with some stray coarse grit particles, perhaps from insufficient cleaning between grits or more rarely, by cheap sandpaper with poorly graded abrasives.
BTW, I prefer a variable speed ROS and usually run it at a pretty slow speed. My favorites are a couple of small pneumatic sanders for smaller work.
I really don't have much trouble with snake trails or swirls. I did with a belt sander I had fifty years ago when I was in the steep part of the learning curve. As for the swirls, the last one I had was when an errant grit got on the work and I did not see it.
One problem that seems to be creeping up on me is my eyesight. Having to work harder to compensate for it. Been upgrading the lighting. Any suggestions? It seems a really strong point source would be good for detecting those last scratches. Actually, I think the sun is best, but then there is that "night" thing.
Mark, that frame really works? Thought it was a gimmick. I will have to check to see if one is available for mine.
the only machines that it fits are several Ryobi's. There was one made for a P-C sidewinder, but I haven't seen that in at least 15 years. I don't think Ryobi makes them any more either, thus the ebay sales links or check garage sales.
You said, "Been upgrading the lighting". You just need to turn your lighting back down until you can't see it. ha
I've got a Oakley stroke sander that really does a great job. The sanding platen on it is covered with a graphite canvas which rolls up on the front and back end. The belts run about 60 mph, and the platen connects to a traveler car above with a lever arm that I apply the pressure with a 3.5 lever advantage, so if I press down, the pad presses 35. One thing I had to quickly learn when I got it, was that it cuts so fast that if I just just traversed up and down the belt while doing wide panels, there would be small steps along the edges of the path from each pass.
The cure was to sand diagonally by moving the table in and out while the platen strokes are left and right, up from one end of the project then swap the diagonal to the opposite on the way back down. ///////\\\\\\\\ This took care of the problem. But once a chip got behind the canvas, which put deeper shallow marks like that.
I have gotten a chip under my hand held Rockwell 503 which will cut a rounded mark, as will a worn out platen, which buckles on the end. That sander is worm drive, and kinda tall and heavy. If a new user accustom to a lighter sander uses it the same way they normally do, the startup torque will tip it over to one side while it spins out getting traction and dig a hole, so it always needs to be started above the work, then engaged while moving the way you intend to traverse. From what I learned on my stroke sander, I adapted that for when I'm using my hand held sander also, as well as lifting some of the weight at the ends when changing direction.
As for the random orbit swirls, I start at 180 grit. If you start with 120, you really need to spend more time with all the following grits to get those deep swirls out.
So, to sum up using the belt sander, inspect the platen and under the backer pad to make sure they are clear and flat. Set the sander on the work, but lift it before hitting the switch, then come in for a landing like an airplane. If the surface is wide like a table top, make diagonal overlapping paths, and lift some pressure off as you quickly reverse directions. 100 and 120 are what I use most.
By the way, I'm not sure most people know that a belt sander will cut faster across the grain, so if you have some tear out like around knots that requires a lot more sanding, you can get that done faster by going across grain first before doing the in-line sanding. Just don't make that a steep sided dish or it will show up after finish.
>>>One problem that seems to be creeping up on me is my eyesight. Having to work harder to compensate for it. Been upgrading the lighting. Any suggestions? It seems a really strong point source would be good for detecting those last scratches. Actually, I think the sun is best, but then there is that "night" thing.
I can see scratches best with small light sources rather than broad, diffuse lighting. Indirect light is the worst and a wide array of overhead fluorescent lights is the next worst. The diffuse light "fills in" scratches with light making them hard to see or invisible. Bright lighting coming from near the eyes, such as over the shoulders, is also horrible.
This first hit home with almost 50 years ago when exploring caves. When I used a headlamp I simply couldn't detect unevenness on the cave floor and I stumbled too much - the bumps and crevasses disappeared. A hand-held light created shadows on the floor making it far easier to walk.
Far better are several small diameter task lights positioned so light is at an angle across the work. Small lights are sometimes referred to as "point sources." I find this especially useful on the lathe and work with multiple task lights on gooseneck or positionable supports. This shows some at my primary lathe:
Overall these lights make it easy to work but coming from different angles not only the scratches but the compound curves are easier to see and judge. If working on a bench or in the middle of the room, I might use a bright flashlight held so the light glances across the surface to check for scratches and other defects.
Another thing I do is wipe a bit of naptha on a surface which can highlight sanding defects. Naptha dries extremely quickly and doesn't raise the grain or seem to affect anything else such as finishes. I keep some handy in a squeeze bottle.
When looking for those pesky cross-grain scratches I turn off the shop lights and use a focused flashlight to light a streak across the board/surface. Scratches jump out as bright spots with I then mark with a pencil.
Also works for finds small dropped screws and parts on the shop floor
Like you my vision has gone south on me. My shop it a 1 &1/2 car garage, full to the max. I have painted the walls white big improvement, but I also have a lot of lights I have 5 2 tube 8 foot, 2 4 tube 4 ft. florescent and 1 4 bulb light fixtures and long with several specialty use lights. In the sanding area I find that dampening the surface of the wood between grits, starting with 150 and working my way up to 320, makes a big difference and gets rid of the swirl marks. Just food for thought.
In a former life we used to rebuild a device with dozens of tiny screws and insulators. I was shown an effective technique for retrieving one of these tiny objects when it left the bench to blend into the "camo" patterned floor tiles. The floor was swept to gather sweepings into a consolidated pile. The part lost was now in this small area and would be easily found.
I use this technique in the shop. If the lost object is magnetic it can be fished out of the swept pile with a magnet. (but usually it is plastic or brass or stainless or a wood chip split away from some part I am working on .....my luck)
