Sanding the inside of the bowl revisited

[Edward Wargo]

A couple of weeks ago I posted the thread regarding sanding the inside of the bowl. The post got quite a few responses and I incorporated the comments into my regimen.
Since then I have been very conscious of my sanding and striving for better results.
I am using a combination of sanding strips and sanding discs, running at 450 RPM, going through all the grits up to 320, followed up with several coats of sanding sealer and Yorkshire Grit.
I'm continuing to see lines, very small lines, but they are visible.

 

[Dennis J Gooding]

Are they sharp (probably sanding scratches) or wide (probably burnish marks and very difficult to remove without re-turning)?

 

[Edward Wargo]

The best way I can explain what I'm seeing is to say the lines remind me of a phonograph, if anyone remembers what they look like.

 

[Clifton C]

This is from your first "sanding inside the bowl" post # 15 you state,

I have been hand sanding so to speak, I'm just holding a piece of sandpaper in my hand while turning 450 RPM.

I think what you are seeing are fine lines from sanding and not tool marks or heel bruise. You have sanding disks, are you using them with a foam backed sanding pad and drill? I use the mandrals and blue flex disks from vinceswoodnwonders.com on an inexpensive angle drill. I believe if you sand with a drill of some type and a pad that you will get rid of those scratches.

 

[Richard Coers]

What do you mean by "all the grits"? Does that mean you are starting with 60 or 80? You can't move to a finer grit paper until all the lines from the previous grit are removed. So if you start with 80, and move to 120, you can't move to 180 until all the lines from the 80 are removed by the 120. Use a direct light to see what is still in the wood, and wipe with a very slightly damp cloth with the lathe shut off, to make sure you can see the scratches. Buy a drill and soft pads to power sand. It takes forever and is miserable when you just hold a strip of sandpaper!

 

[Edward Wargo]

Are they sharp (probably sanding scratches) or wide (probably burnish marks and very difficult to remove without re-turning)?

I finally took the piece off the lathe and finish sanded it by hand on my bench,

 

[robo hippy]

Hmm, thought I responded to this, but don't see it up here... The sanding scratches are visible to the human eye up to about 600 grit, so 320 and 400 will be visible. I sand to 400, then take one of the grey Norton synthetic pads to apply the walnut oil finish with, That makes the scratches go down to the invisible level...

robo hippy

 

[Owen Lowe]

I find that if I polish the wood between grits it makes scratches stand out much more obviously. You can use steel wool, Scotch-Brite or, my favorite, dry wood shavings. 10 or 15 seconds against the spinning wood seems to do the trick for me.

 

[Gerald Lawrence]

Hmm, thought I responded to this, but don't see it up here...

robo hippy

Think this got posted twice.

 

[hughie]

Sanding inside, I tend to use inertia type sanders as they leave a finish, in general, that is higher than the grit being used. Rarely do I hand sand inside as its too prone to leaving lines. Actually, they are used both inside and are they are my 'go-to' sanders, probably have close to a dozen or so.

 

[John Turpin]

I hate sanding. I keep waiting for a volunteer to step up and do it for me, but the volunteer ranks remain silent.

 

[Richard Coers]

Hmm, thought I responded to this, but don't see it up here... The sanding scratches are visible to the human eye up to about 600 grit, so 320 and 400 will be visible. I sand to 400, then take one of the grey Norton synthetic pads to apply the walnut oil finish with, That makes the scratches go down to the invisible level...

robo hippy

He posted this question twice, so 2 lines of answers going.

 

[Marc Himes]

I am a fan of power sanding with a drill. I use a hook and loop pad holder with an interface pad 3",2" or 1", depending on the angle of the curve. Using a disc that is larger than the pad is helpful in getting the sand paper to "turn the corner" and sand the wall of the bowl. I also like to slightly wet the bowl with a small amount of water between coats, once I get up above 180.