Sanding scratches in finished bowl...

[Dan Forman]

Now I know that this sort of thing would never happen to me, or any of you for that matter, :cool: but hypothetically speaking, what would you do if you just finished sanding a bowl inside and out, checked it out thoroughly before parting off the last of the tenon and sanding the bottom, then applied a little mineral spirits to bring out the color and grain and see what it would look like when finished... and to your horror spotted some not too subtle sanding scratches on the inside of the bowl. :eek: There is no longer any means of getting it back on the lathe. Would you just go ahead and finish as is, or try another method of sanding to clean it up?

Dan

[Chuck Rodekohr]

You could try one of the soft sanding disks in your power drill, like this http://www.woodcraft.com/Product/2000275/2287/2-SORBY-Foam-Sanding-Pads.aspx

[Steve Trauthwein]

Dan,

Not that this has ever happened to me but I always take a piece off of the lathe with chuck attached and take it to a good light source to apply a coat of finish and inspect the surface. Sanding is not fun, sanding off of the lathe is really not fun!

Regards, Steve

P.S. Try power sanding with a soft disc.

[Jim Evans]

I'm my worst critic on how my turnings look and I would have to make it right.
I'd would get those scratches out somehow.

[Steve Kubien]

Well it is good that this sort of thing never happens but if it wedre to happen in my shop I think I would have a new ready to use bowl in my house. Let me explain...

A few years ago I made a really ugly bowl (profile experiment went wrong). I could not bear to put my name on it, let alone try to sell it, so it came into my house. I use it every couple of days and it is my favourite bowl in the place. I leave it SOAK in the sink, I put it in the DISHWASHER, I use STEEL utensils... I beat the h*ll of this thing and it keeps coming back for more.

The other point from my persepctive is the PITA-factor of what you are trying to do. It would drive me nuts and it would end up sitting on a shelf for months. That's just me though.

Oh yeah, never part off a piece until you KNOW you can. Nope, never happens around here... -sigh-

Steve

[Dave Schell]

Dan, I power sand bowls routinely off the lathe using a 2" soft foam backing pad and a power drill. It's an excellent way to get rid of the concentric sanding scratches caused by sanding on the lathe.

I'm confused why this is perceived as such a pain? What is the downside that I am missing that would cause one to think the bowl has to be tossed?

[Cyril Griesbach]

If you don't want to hand or power sand it with a drill consider chucking up your sanding mandrel in the drill press and doing it that way.

[Robert McGowen]

If you have always wanted a vacuum chuck, but never built one, this would be the time. Suck that bowl back onto the lathe and give it a spin. No problem at all............

[Harvey M. Taylor]

One more reason for a vacuum setup. reduce the suction, move it around till it is close enough, increase the suction and sand away.Hopefully helpful, Max

[Dave Schell]

Dan notes in his original post that the scratches are on the inside of the bowl. Vacuum chucking would obscure access to that, right?

[Ted Calver]

Dave,
Vacuum works on the outside too. You just need a big enough chuck to enclose whatever you have done for the base.

[Jeff Nicol]

Dan notes in his original post that the scratches are on the inside of the bowl. Vacuum chucking would obscure access to that, right?
Dave, If the vacuum chuck is round and the base will fit in the opening of the chuck it can be mounted the other way also. Lots of chucks are made from PVC pipe of different sizes with a soft cusion of some sort that touches the wood. So no problem at all!

Jeff

[Jerome Hanby]

You could grab a keyring of old keys, a homemade flail, or whatever and further distress the bowl and make the scratches work for you.

[Dave Schell]

Dave, If the vacuum chuck is round and the base will fit in the opening of the chuck it can be mounted the other way also. Lots of chucks are made from PVC pipe of different sizes with a soft cusion of some sort that touches the wood. So no problem at all!

Jeff

Hmm - never thought of mounting like that! I guess because I've never had that need - but good to plant that thought somewhere in my brain. Thanks!

[Reed Gray]

Well, since I don't remove my recess, it isn't a problem for me. Of course, getting all the scratches out first is the solution, but that isn't always easy. Mike Mahoney says he always starts sanding with 80 grit. I try to avoid that as 80 grit scratches are as difficult to get rid of as tool marks some times. I do spend extra time on the 120 grit when I start with the 80. I do sand to 400 grit because 320 grit scratches are visible, and 400 only if you really look. I used to use stiff paper backed discs. They were agressive, but becausse they were so stiff, the paper would leave swirl marks in the wood. I now use the film backed discs. I use a firm interface pad (from Vince) with a quarter rounded profile on the outside edge. The firm pads are used up to 220 or so grit, and the softer pads to 400. The rounded edge greatly helps on the inside of the bowl. I don't wipe out or blow out the bowl between grits, except at the higher grits. The fine powder will go down into scratches that were left behind. Before the finish goes on, I will wipe the bowl down with my hand and slowly spin it to find any remaining scratches. I use a multispectrum light (Ott is one brand, Blue Max is another, used to advertise on Woodturning design, and the quilters and hand sewing people know about them) as it shows scratches better than other types of lights. You could take it out into the sun light to see. Other than that, a power sander and sit the bowl in your lap, have wind to blow the dust away, and/or a positive pressure mask.

robo hippy

[Bill Bulloch]

I'm sure that I am the only one that this has actually happened to -- as-a-matter-of-fact several times. While I am watching TV in the evening, I take a small box just a little larger than the bowl, put the bowl in the box, put the box in my lap, and start hand sanding with a low grit sand paper and work my way up in grits until I'm satisfied with the piece. The box catches most of the wood flower (at least that is what I tell the wife). Somehow-another, doing it this way doesn't seem to be such a chore.

[alex carey]

i'd finish it right then and there by throwing it on the ground and shattering it.

I just start a new. I hate sanding, especially off the lathe, why is there no way to put it back on the lathe?

[Dan Forman]

Already got rid of the tenon, no vac chuck yet. I might just sit on the bowl until my vac chuck is ready, forgot that you could mount it on a cylindrical vac chuck from the back.

Dan

[Harvey M. Taylor]

In addition to my last post, the Mlarger the pvc chuck the better.Max

[Ryan Baker]

Mike Mahoney says he always starts sanding with 80 grit. I try to avoid that as 80 grit scratches are as difficult to get rid of as tool marks some times.

I suppose I would do that too if I had someone to do the sanding for me like Mike does. :)

[Thomas Canfield]

What ever happened to manual sanding? Depending on the type and location of the groves, that often seems to be easier than using some power in the final stages. Also, buffing with tripoli does a lot to remove (or fill) minor groves and scratches especially down in the 320 and 400 grit stage.

[Dan Forman]

I brought it over to a friend and mentors shop, he thought the scratches were very minor, so we put it on his vac chuck, hit it with 320, soaked with a wipe on varnish and wet sanded with 400 grit. I'll let that dry, then wet sand again with varnish and 600 grit, then one more coat and buff after about a week. Thanks to all who have contributed suggestions. From now on, I'll wet with spirits and look for scratches before severing from the chuck.

Got to get going on my vac chuck. So many projects, so little time.

Dan

[Bernie Weishapl]

I do pretty basically like Reed does. I go firm to 220 or 240 the soft on 320 and 400. I wipe it down with either DNA or mineral spirits with a good light source before I take it off to finish the bottom. It will show scratch marks and then you can finish sanding those spots. Sometimes I will go back and hand sand with 320 and 400. Two things I have observed with some turners is they don't blow or clean the bowl of sanding dust between grits or skip grits.

[Dick Gerard]

I am rather OCD when it comes to my sanding and finishes, but a beautifully turning can be reduced to ho-hum by sanding scrathes, yet a so-so turning with a beautiful finish is still well received by potential buyers (assuming they are not turners!).

From some 30 years of experience, here is what I do on each and every turning.

Before doing anything, clean your glasses and face shield! Be sure you have plenty of light ... like chocolate or macadamia nuts, you can never have too much. Remove face shield to inspect the piece. Wear 10X magnifiers if there is any doubt.

When I "think" I'm done with a particular grit, I use compressed air to blow off the dust, then I wipe some mineral spirits over the whole piece. Don't worry, the mineral spirits will evaporate quickly. The mineral spirits will highlight the sanding scrathes. Circle them with a soft #2 pencil. With the lathe OFF, power sand the scratches away. Repeat blowing away dust and do the mineral spirits again. If all is well, move on to the next grit. If you have a reversing lathe, reverse it every other grit.

When you are "satisfied" that you have removed all tool marks and sanding scrathes, AND BEFORE parting off, take the piece still mounted in the chuck, in to your spouse for a final examination. She or he will find those elusive scrathes in an instant!

One other trick. Wipe the end grain with a coating of paste wax. Wait a couple of minutes and wipe off briskly. This will also highlight sanding scratches.

Don't ask me how I know ANY of this stuff.

[Steve Mawson]

I used a 2" disk from Vince on the last one that the tenon broke off of. Worked out pretty well. That was on the inside and also used on the recess where the tenon used to be.