Scratch Free Sanding

[gr8mesquite]

At the urging of my friend Farley I've cranked up the SS lathe and have started turning in earnest. Based upon my internet reading, the mark(s) of a true amateur turner are the sanding scratches swirling through the finished piece. I'm definitely a rank amateur because i have lots of those. Apparently my instincts were dead wrong--sanding is not so easy and is not just a matter of holding a piece of sandpaper on a turning piece of wood.
So, having learned that lesson, my question to you is "What sanding method/system/pad/tool etc. do you recommend for those beautiful, smooth, scratch free pieces you turn?

Many thanks.

[dusty]

At the urging of my friend Farley I've cranked up the SS lathe and have started turning in earnest. Based upon my internet reading, the mark(s) of a true amateur turner are the sanding scratches swirling through the finished piece. I'm definitely a rank amateur because i have lots of those. Apparently my instincts were dead wrong--sanding is not so easy and is not just a matter of holding a piece of sandpaper on a turning piece of wood.
So, having learned that lesson, my question to you is "What sanding method/system/pad/tool etc. do you recommend for those beautiful, smooth, scratch free pieces you turn?

Many thanks.

I am not a turner but I think the answer is the same for all sanding projects.

Work your way through the grits.

[terrydowning]

Sanding on the lathe is not the same as sanding flat work.

First things first. Safety Safety Safety

Get the tool rest out of your way. Getting fingers caught between the spinning piece and the tool rest is definitely not good.

Wear all face/eye/respiratory protection that you would during turning or sanding operations.

Keep the speed low while sanding this helps keep the temp down and allows to make corrections while sanding.

On to the actual sanding.

Sanding is about getting a uniform scratch pattern at each grit level and then moving on to the next higher grit until the scratches are so small they can not easily be seen. A random orbit sander helps achieve this by causing random swirl marks, the person doing the sanding still needs to get uniform marks on the finished project though.

Whatever grit you think you need to start at go one step more coarse. If you think you should start at 100/120 then drop down to 80. If you think you should start at 80 drop down to 60. Remember you are machine sanding and the grits will leave a finer result than they would hand sanding.

First get rid of the tool marks if you have too, these will be deeper. As your turning skills improve, this will need to be done less and less. Next, strive for a uniform scratch pattern at your starting grit, if won't get there and you have larger scratches, then drop down a grit coarser.

Once you have a uniform scratch level, STOP the lathe. Sand your turning with the grain at that grit level.

Clean off your work before moving to the next grit , wipe, blow gun, vacuum your preference. but get rid of the left overs and possible contamination.

Move to the next higher grit and repeat striving for that uniform scratch pattern.

Keep repeating the process through the grits until you reach your desired level of scratch pattern.

This same general pattern/process holds true for polishing as well. Achieve a uniform pattern, go with the gran, clean, move up in grit level.

Things to watch out for.

Overheating. It's really to over heat. I sand using my hand and fingers. If it gets hot to the touch stop and let things cool down.

Don't scrimp on the sand paper, you really do get what you pay for and using dollar store sand paper is a false economy. Better quality cloth backed paper lasts longer and stays cleaner.

That being said. Sand paper does not last as long when sanding on a lathe. You are power sanding after all.

Keep the paper moving on your turning, this helps keep the heat down, makes the paper last longer and helps reduce heavy scratches. Part of keeping the paper moving is changing which part of the paper is in contact with the wood.

Like all things wood working you need to practice and experiment to get the best results you can get.

Don't over sand. Sanding a bowl to 400 or 600 and then trying to add a finish coat of Poly or lacquer does not work well. the surface is too smooth and then finish will not adhere well. Sand to the level that your finish adheres to I prefer 220 or so if going to use lacquer pr poly. 320 if going to CA.

Resume sanding on the finer grits once the finish is dry at each application of finish and then start your polishing regimen.

This is how I learned and how I do it. I'll let my results speak for themselves.

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[benush26]

Basically I do the same as Terry, but at final grit I do two more things. One is I usually take a damp paper towel to the surface to raise the grain, usually while it's spinning. The other is that with the PowerPro, I reverse the motor, lightly and quickly sand.

Just my method so it may not work for you.

Be well,
Ben

[reible]

Few additional hints.

If you can't see the flaws does not mean they are not there.

I found as I've gotten older I don't see anywhere as well as I wants did. I started using reading glasses and did so for reading printed as well as computer screens. The focal length of those glasses ended jut before it got to pen size pieces on the lathe. With my new glasses that has gone away. However with a face shield on I'm back to "missing" things. So hint one is to make sure you can clearly see what the work piece looks like as you sand and when stopped flip up the shield and really look.

Next is good lighting. It goes without saying that to see your work you need good lighting. In fact one of my current issues is that the ceiling florescent light is slightly behind me at the lathe. I want to move it so it right over the lathe. I've also added supplemental lighting by way of a bright LED lamp.

Mineral spirits wiped on the wood can also make it easier to see scratches.

Then there is wood that sands nice and wood that does not even in the same block. Some woods have soft and hard places and while the soft area clears up quickly the hard places might still be showing marks. So woods are also prone to clog your sandpaper where others do not. They make sanding screens which really helps with the clogging type woods.

I agree that the reversing function can help on the powerpro sanding operations, I often go up the ladder of girts switching direction on each change. Again this works better on some wood then others.

Bottom line is there is no best way for all projects, ash handles I've turned have a lot of open grain structure and I would hate to have to get to a near polished state. The good news is that since they are handles for lathe tools they don't need or want them that polished.

Ed

[terrydowning]

Ben and Ed bring up some very good extras.

I don't have reversing capability so.... If I did, I would alternate rotation between grits.

A small very bright LED flashlight is great way to provide raking light (Light held at an angle) that will expose many scratches not seen in straight light.

Mineral spirit wipe down does 3 things.
Exposes scratches and flaws
Removes the dust and grit from the previous sanding
Gives an idea of what different finishes will look like.
Just applied glossy wet
Once it starts to flash off less glossy satiny finish.

I usually do a mineral spirits wipe down as the last step before finishing then go back and fix anything before applying any finish.

Warning here. If you are using a water based finish let the MS completely flash off before applying. (I wait overnight)

And as Ed has stated the level of polish is totally dependent on the project.

[gr8mesquite]

Good stuff here. Thanks.
Terry...your bowls are dynamite.

[skou]

Jerome, as a kid, I was always taught to sand with the grain, not against it. Difficult to on a lathe.

Terry, I used acetone on Koa wood, for the same purpose, and it would darken the wood. Long time ago, when I was living in Hawaii, a friend wanted me to smooth off a couple pieces of Koa, so he could turn them into a bar top. That wood is so hard, I was able to get a decent surface with a rubber sanding block, and some 80 grit paper. Every so often, I'd wipe it down with an acetone soaked rag, just to see what it'd look like finished. The surface always stayed a few shades darker.

steve

[terrydowning]

That's the wonderful thing about using living materials like wood. They are all different and while they share common characteristics, they all have their unique traits and properties.

It takes practice to learn what different woods will do.

[kalynzoo]

Even though this was not my question, I am following you guys with great interest. Sanding and finishing has traditionally been my weakest function. So thank you for the many tips.