# Concentric circles at bottom of bowl



## DirtFarmer (Nov 10, 2020)

Hello all,

I come to you for wisdom and guidance. I have done a few practice bowls out of cheap wood, and today I finished one that looks nice (maple). However, each time, I end up with very thin concentric circles in the bottom of the bowl. Is there any advice on how to get them out/smoothed? I have tried sanding at low grit, but it doesn't seem to help much ...


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## Maverick (Nov 10, 2020)

Hi Jason, are you able to post any pictures? That might help in the diagnosis.


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## DirtFarmer (Nov 10, 2020)



Reactions: Thank You! 1 | Sincere 1


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## DirtFarmer (Nov 10, 2020)

Maverick said:


> Hi Jason, are you able to post any pictures? That might help in the diagnosis.




Okay, let me see if I get it right.


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## Maverick (Nov 10, 2020)

I am in the beginnings of the learning curve myself, but I knew pics would help. I am sure there will be some knowledgeable folks that will come along to offer advice.


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## T. Ben (Nov 10, 2020)

I’ve had that happen to(in the first pic) I’ve sanded them out and I’ve used a round nose scraper to even things out. Mine have been kinda wavy,not like the second pic.

Reactions: Agree 2


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## T. Ben (Nov 10, 2020)

What tools are you using? Carbides or tradition gouges?


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## DirtFarmer (Nov 10, 2020)

T. Ben said:


> What tools are you using? Carbides or tradition gouges?



Traditional gouge.


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## barry richardson (Nov 10, 2020)

A clean up with a negative rake scraper should do the trick, you can use a skew chisel laid flat on its side for this function. Also if the bowl is big enough, a random orbit sander works great for getting out those lines...

Reactions: Agree 2


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## Gdurfey (Nov 10, 2020)

I recognize those rings!! Been there, and still do that. As the folks up above have stated will make a huge difference. I recently found 3 different round nose scrapers on sale and bought all 3 (yes, I splurged) but they have different radii (I know radiuses is not correct.....). They have made that final pass come out much better. 

I think the rings are caused by us not quite picking the next cut up where we need to, going a little deep (very little) or the same on the shallow side. Unless you go clear out to the outside and take a single cut all the way to the center you are apt for these.......I think. Or, at least that is my understanding. I will let the true experts chime in, I just felt like typing to someone this afternoon.

I have also found the big scrapers to be much better than carbide at this clean up. Similar concept, but the scrapers I bought (forgotten brand name.....) are beefier, and provide a wider contact area to smooth out those small imperfections. 

best wishes and keep turning. Oh, Barry’s comment, I have a small sander that takes 2 inch and 3 inch discs. Not random orbit, but works great.

Reactions: Like 2


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## DKMD (Nov 10, 2020)

Typically, I get rings if I’ve lost bevel support during the cut or if the heel of the gouge is bruising the wood. Those look more like the former than thw

Grinding away some of the heel helps with both issues. The shorter bevel is often easier to keep in contact in transitions/concave curves, and grinding away some of the heel prevents the bruising that can occur.

Also, too much pressure pushing the bevel into the wood can induce bouncing which leaves a similar surface.

Hang in there... it’ll get better with more practice!

Reactions: Agree 1 | Useful 1


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## trc65 (Nov 10, 2020)

All good comments above, so I wont repeat. 

What grit are you starting to sand with? On your bowls, I'd start with 60x or 80x and work up through the grits. Using a power sander is the only way to go. Before I bought a (corded) right angle drill for sanding, I just used a 2" or 3" disc on my cordless drill.

I sand with the lathe turning at the lowest speed, and the drill at only half speed or less. If you've got spots that are stubborn, sand those areas with the lathe off, and then sand with the same grit and the lathe turning to feather out those areas.

Edit: I should mention that it's always better to clean up your project with tools as much as you can before you start sanding, but when you get problems, don't be afraid to go low with your starting grit.

Reactions: Agree 2 | Useful 1


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## Mr. Peet (Nov 10, 2020)

trc65 said:


> All good comments above, so I wont repeat.
> 
> What grit are you starting to sand with? On your bowls, I'd start with 60x or 80x and work up through the grits. Using a power sander is the only way to go. Before I bought a (corded) right angle drill for sanding, I just used a 2" or 3" disc on my cordless drill.
> 
> ...



Assume lathe turns one direction with sander in the opposite when using the drill sander? 

@barry richardson 

Barry, how slow is the lathe turning the piece when sanding. With an orbital sander, what is better, one with a vacuum line or one that allows the sandings to tumble in the turning?


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## trc65 (Nov 10, 2020)

Mr. Peet said:


> Assume lathe turns one direction with sander in the opposite when using the drill sander?



That's correct, although you can vary the scratch patterns by using just one portion of the pad at a time. When I change grits, I try to use the opposite side of the pad, i.e. top/bottom or left/right. Sounds better in theory than it always works in practice, but it does help seeing when scratches from previous grits are removed.

Reactions: Thank You! 1


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## Tony (Nov 10, 2020)

If your lathe has reverse on it, it helps to sand in both directions. At least for me it does!

Reactions: Like 1 | EyeCandy! 1 | Agree 3


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## barry richardson (Nov 10, 2020)

Mr. Peet said:


> Assume lathe turns one direction with sander in the opposite when using the drill sander?
> 
> @barry richardson
> 
> Barry, how slow is the lathe turning the piece when sanding. With an orbital sander, what is better, one with a vacuum line or one that allows the sandings to tumble in the turning?


I normally power sand off the lathe, ROS by design cancels out scratches, which is why I like using them, inside and outside up to 320, can't use them on small pieces though


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## Nature Man (Nov 11, 2020)

Why do we love sanding? Because that is what it takes to make a bowl (or whatever else you turn) into a masterpiece. Wait, most of us don't really like sanding that much. Chuck

Reactions: Agree 1 | Funny 2


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## duncsuss (Nov 11, 2020)

DKMD said:


> lost bevel support during the cut or if the heel of the gouge is bruising the wood



What Doc says, it's one or the other of these. In my experience, very fine lines are caused by the tool tip (lost bevel support) and the wider kind of scrapes are caused by the heel of the bevel crushing the wood fibers.

Check out this link for a drawing of what "relieving the bevel" means ... LINK

It's really easy to achieve whatever method you use to sharpen your gouges - with a Varigrind, just push the tool forward from the handle pocket; freehand just stick a finger between the platform and the shaft of the tool, and lower the handle so it contacts at the edge of the platform nearest you.

Reactions: Agree 1


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