Sanding technique and ensuring flat, even result

[ReneS]

As i work more carefully, I find sanding to be much more technical than I ever noticed before.

I don't mean avoiding swirls and the progression of grits. I mean avoiding the introduction of waves or undulations in the surface.

I used to just move the sander around until the surface looked smooth and any joints were flush. This is mostly with panels made with mortised stiles and rails.

Now that I see how bad that can be, I am trying to sand evenly, and remove the same amount of material everywhere on the rails and stiles.

All I can think of is counting (like 1, 2, 3, 4) and then moving over a little less than the size of the sander pad, counting again, then moving over, etc.

I'm thinking that should result in much more even removal. I'm hoping that with minimal overlap each time I move the sander, the sander will be above the old
section until it drops down at the end of the count, and that it will then be flush with the old section.

Does anyone have a better way to sand other than using a big drummer sander?

Thanks

 

[smorgasbord]

First, if you're not using a hard pad, get a hard pad and use it. The medium pad on some woods where the growth alternates between harder and softer will sand differently with not-hard pads.

Another tip is to use pencil marks. Lightly pencil the board and sand just enough to remove the pencil marks. If you apply the pencil marks pretty evenly and sand them off evenly (and don't keep going where the marks are already sanded), that might help, too.

 

[luvmytoolz]

As noted above a hard pad is good, but another aspect is what media re you using?

If using Alu Oxide discs, these usually have a firm backing so are ideal with a hard pad, but these wear pretty quickly and the result is you subconsciously tend to increase the down pressure, which can lead to undulations.

If you haven't tried them the big 3 mesh disc types (Abranet, Granat Net, Cubitron 2) give a faster, more consistent cut, so might be an advantage if so concerned. I now use the mesh discs pretty exclusively as the results and cost value are so good.

 

[ReneS]

As noted above a hard pad is good, but another aspect is what media re you using?

If using Alu Oxide discs, these usually have a firm backing so are ideal with a hard pad, but these wear pretty quickly and the result is you subconsciously tend to increase the down pressure, which can lead to undulations.

If you haven't tried them the big 3 mesh disc types (Abranet, Granat Net, Cubitron 2) give a faster, more consistent cut, so might be an advantage if so concerned. I now use the mesh discs pretty exclusively as the results and cost value are so good.

I'm using granat on a hard disc using the Ets ec 150 5 (if I've got the model right).

 

[luvmytoolz]

I also use the ETS EC's (which are the best sanders I've ever used), and try to maintain a light hand on the sander and float it over the surface without dwelling on any spot too long.

If you're getting undulations with a Granat disc and a hard pad, are you applying too much pressure?

 

[ReneS]

I also use the ETS EC's (which are the best sanders I've ever used), and try to maintain a light hand on the sander and float it over the surface without dwelling on any spot too long.

If you're getting undulations with a Granat disc and a hard pad, are you applying too much pressure?

It's possible, but i try to let the tool do the work.

It's such a nice sander and so balanced, I mostly rest my hand on top and let the weight of my arm apply the pressure, at least that's what I think.

I probably was running it too fast. I'm thinking a short time difference (a few seconds) could make a noticeable difference in actual removal.

Counting has helped.

 

[luvmytoolz]

Trial and error I guess, I find slower speeds to give a better result generally. I could be imagining it but the media also seems to last longer and remove more.

The EC's are such a joy to use aren't they, I love mine. Definitely recommend a box of the Granat Net if you're only using the ordinary Granat, I think you'll be stunned with the results.

 

[ReneS]

I'll give that a try. I have the regular granat.

And yes, the sander is a joy to use.

 

[hdv]

What the others already said: use an appropriate pad with the right paper. In addition to that sand evenly over all of the surface. Don't get temped to focus on bad spots. Let the sander do the work, don't push it too much. In most cases the weight of the sander itself will be enough. Try not to lift the sander too much. Just keep on sanding in long smooth strokes. Also mind what you are doing when beginning and ending. Put the sander on the surface and turn it on, not the other way around. Unless you are very precise and let the pad touch the surface exactly flat to it, you will sand unevenly. When lifting the sander off the surface do exactly the opposite: first lift and then turn it off. With delicate material or when you want to be extra careful, put the sander on medium speed. That way mistakes will result in smaller blemishes.

 

[Steve1]

Does anyone have a better way to sand other than using a big drummer sander?

I find my random orbit gives a far smoother finish than my drum sander, using same grit. So that is not a great solution. But a drum sander is very handy for flattening a glue up. (but scrape those glue lines well, glue will clog up my sanding belt in no time, and turn the belt into trash)

Try the pencil marks as suggested in the first response. If the pencil marks are disappearing evenly, your material removal is even. Pretty soon you will get a feel for how much sanding you need to do. I don't use the pencil marks on the final grits for fear of finding a little mark after applying finish.

 

[jeffinsgf]

All I can think of is counting (like 1, 2, 3, 4) and then moving over a little less than the size of the sander pad, counting again, then moving over, etc.

I'm thinking that should result in much more even removal. I'm hoping that with minimal overlap each time I move the sander, the sander will be above the old
section until it drops down at the end of the count, and that it will then be flush with the old section.

Thanks

Either I'm misreading this, or you're sitting in one place and then moving, which I would not do. I try to keep the sander moving in smooth, broadly overlapping strokes, first pass across the grain, second pass with the grain. Hard pad. My current abrasives of choice are Cubitron 2 in lower grits up to 180 and standard Granat in 220 and up.

 

[ReneS]

I appreciate the replies. Thanks everyone.

Jeffinsgf - Thanks. I was thinking I was moving slowly, but i see your point.

Previously, I moved around in long strokes but also worked on the rougher spots. I wanted a way to ensure each area was getting the same amoint of sander time.

One thing I noticed was that the middle of a back and forth stroke got double time, as did the starting point. The end point needs a pause to keep up.

I'll go back to moving more and being more conscious of how much time I spend on each area.