Sanding - the 80 Grit Gouge

[mrGeeze]

After turning green wood for a few months I finally have some roughouts i can finish. I have tried a number of options for sanding some of which work ok and some of which don't seem to do the job. Normally I work from 80 to 120, 240 and 400. I stop after 400. Then its mineral oil, and the Beall Buffing System.
I was wondering what approaches (power,hand, etc) work best. I'm especially interested in approaches that would save some time.

Thanks.

 

[pyrocasto]

After turning green wood for a few months I finally have some roughouts i can finish. I have tried a number of options for sanding some of which work ok and some of which don't seem to do the job. Normally I work from 80 to 120, 240 and 400. I stop after 400. Then its mineral oil, and the Beall Buffing System.
I was wondering what approaches (power,hand, etc) work best. I'm especially interested in approaches that would save some time.

Thanks.

I believe power sanding is the easiest/quickest way if you are starting at 80, but I still hand sand.

I think addding some more grits may save you a bit of time. I go 80, 100, 120, 150, 180, 220, 320, 400, 600. Seems like less grinding on each grit.

Though I think the best answer if possible is to get a good clean surface with a sharp gouge so you can start sanding at 180-220.

 

[TurnedAround]

A lot of folks use this:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92956

chucked up with these:

http://www.tools-for-woodworking.com/index.asp?PageAction=VIEWPROD&ProdID=3264

 

[MichaelMouse]

Power beats hand every time. Not only can you drag more grit-inches per minute with power, you can also do the sensible thing and cut across the gouge marks at the outset, and randomize scratch marks from there on out if you watch what you're doing.

I don't think forty grits and powered drills are the best way to go. I use a supported sander, a real "80 grit gouge," and have more than four grits at hand only because the velcro backs don't follow the same progression as the hard backs. With a supported sander you can cut wood almost without pressure as the piece is rotating, and by taking advantage of the point of contact on the rotating disk, sand in any direction. Your arm doesn't get tired, the paper isn't supported by what it's sanding, so it doesn't heat, burn and burnish as easily, and the grit stays on the backing. Technique is pretty much the same as using a scraper, except the end of the scraper is rotating.

Probably the most important thing to remember about sanding is if it shines - stop! Shouldn't shine. Should be covered with dust. Shine means you're not cutting, just buffing. Set up the fuzz and break the case-hardening with a damp rag and repeat the grit. Opposite of a gouge, where you're looking for the shine of a cut rather than the matte of a scrape.

 

[Frank Kobilsek]

Geeze
All true but if your lathe has reverse use it on every other or every third grit. It stands up the fibers and lets you cut them off. Try it you'll like it.

If hand standing fold with course grits fold the paper over a stiff piece of cardboard or thin piece of wood. The flat surface will knock off high spots/ridges you may have left with your gouge. We should all try to get our shape with a tool not sandpaper but sometimes it just won't come so sandpaper has to fix it.

Frank

 

[john lucas]

What about just sharpening the gouge and making a final pass so you can start with a higher grit. I used to start with 120 grit all the time (occasionally 60,80 or 100 depending on the wood) but I found that reaching for the 120 was a force of habit. Lately I've been concentrating on my cutting technique and then reaching for the appropriate sandpaper, sometimes as high as 220 if I'm lucky.
What I'm trying to say is that it's too easy to just reach for the 80 grit when in reality you might be able to start with a higher grit. On the other hand I see my students starting at 120 and sanding forever or maybe not enough because they should have started with a courser grit to get rid of tearout etc.
I now push myself to achieve a finer finish off the tools. This not only faster but uses less sandpaper. Now that I've switched to the Norton 3X I'm a little more particular about wasting sandpaper.
If you have a particularly bad section a card scraper will deal with it very quickly and won't accentuate the summer winter wood lumbs the way sandpaper will.

 

[Jake Debski]

Gotta ask......................

.................................................................. I use a supported sander, a real "80 grit gouge," and have more than four grits at hand only because the velcro backs don't follow the same progression as the hard backs. With a supported sander you can cut wood almost without pressure as the piece is rotating, and by taking advantage of the point of contact on the rotating disk, sand in any direction. Your arm doesn't get tired, the paper isn't supported by what it's sanding, so it doesn't heat, burn and burnish as easily, and the grit stays on the backing. Technique is pretty much the same as using a scraper, except the end of the scraper is rotating.

I've not heard the term "supported sander" before. Could you elaborate? 😕

 

[Steve Worcester]

I would highly recommend the last pass with a sharp gouge practice. Use either a finish cut on a fingernail grind, or a Bosch gouge made for the finishing cuts. The Bosch is a traditionally ground gouge with the wing swept back on the left and the wing vertical on the right. Left is for concaves (inside of the bowl) right is for convex (outsides).

While I am a big fan of powersanding, since I use and test all the sanding products I sell, I would like to stress this.
Sandpaper is a cutting tool, but is a poor substitute for dull tools. It becomes real noticeable with the woods we have, if you sand alot. You will get waves, undulations from the density difference of the early and late wood across the growth rings. Run your hands across a bowl after you have finished sanding, and feel for the peaks and valleys. I am not saying that sanding won't work, but with practice, less sanding is better.

That said, I would say start with whatever you need to eliminate the tearout and gouge marks, 60, 80, 120, whatever. Then go through the grits in your system. I go 80, 120, 180, 240, 320, 400, and up. Some add more in between. Clean the surface off in between grits, either by blowing it off, or running a tack cloth or something. Keep the paper moving, don't run it too high of speed, either the wood, or the drill. This will keep the heat down and prolong the life of the paper and the pad. If you can reverse your lathe, that can also be helpful. The other option is to remove the paper after each grit and (with the lathe off) hand sand in little circles to help randomize the swirl marks.

 

[MichaelMouse]

I've not heard the term "supported sander" before. Could you elaborate? 😕

Sure. I use a flexible shaft powered by a fractional horsepower 1725 motor. If I rest the handpiece on the toolrest, as with any other tool, I can let the wood come by and keep a soft touch on the piece, rather than supporting the paper on the surface. Same idea as not pressing the bevel as you're making a cut, where it soon starts to follow the path of least resistance, leading to bounce. Support independent of the piece, coupled with the hard-back sanding mandrel, makes its own surface rather than following the differing grain and density you encounter with end/face transitions and soft spalt.

You can also disregard a couple of sanding axioms, like "slow the lathe down" when sanding, and "reverse the lathe" to get a smoother surface. The lathe can be running at a decent clip, because you won't have to counter a lot of force with the pad barely contacting, and depending on the portion of the sanding disk that meets the surface, you can sand in any direction as long as the disk and lathe aren't at the same speed. Not that it makes a difference after you're done with gross gouge ridges, where you want to sand at or close to 12 or 6 o'clock on the disk, to maximize the cross-groove component. Finishing each grit at 9 or 3 o'clock gives you a closer approximation to hand-sanding.

Though you can't avoid using the edges of the disk on inside curves, you can use the center exclusively on outside curves, distributing the wear on your paper better. With no pressing, you don't heat the surface of the wood or paper much, more easily avoiding burnishing and grit throw.

After you get to 320 you can certainly go further with soft-back sanding, but the source of swirls is usually the edge of your sander biting and bouncing on a small segment of its circumference, so you want to be really careful about that if you stop the lathe. Saves buying those funny scalloped disks to avoid digs, though.

 

[KenN]

I've a suspicion that we use what works for each of us and that may all that counts. To add to the mix of practice: I use an angle drill rotating against the rotation of the surface I'm sanding and begin with the finest grit my final cut needs. Usually 100 or 150. I do have an 80 and even a 60 grit gouge in reserve when a not-quite-concentric piece (changing dimension as I cut - should that never happen to you) leaves grooves I cannot cut out without penetrating to the outside. In that case, I sand the tough places without the piece turning, with care to fair the surface as much as possible. When the offending grooves are removed, I turn the lathe on (different RPM than the sander) and clean with the grit I last used before proceeding to finer grits. I use 60, 80 (both reserve "gouge" grits), 100, 150, 220, 400 and finish with straight tung oil. Different species seem to take finishes differently, but that is the nature of organic materials.

I really enjoy the variety of experience and practice out there!

 

[TurningDog]

I've a suspicion that we use what works for each of us and that may all that counts.

It is all that matters. There are problems that have to be recognized with every method like for example power sanding is prone to give you uneven spots on the piece and is often the first choice of the lazy or inept turner. Then there are inertia sanders which many people claim are just too slow and won't use it no matter if it is the right choice for the job or not. Then there are those purists who think any sandng you do below 180 grit means you simply are an incompetant turner and they will only use high priced sand paper and do it by hand. (laugh all you will when I first started turning a local guy in the group chuck bowls even from expensive blanks in the trash if he was required to go below 150 grit because they simply weren't worth his time).

For me sanding is whatever seems appropriate to the job. I am jus as likely to look at a great spalted blank and grab for a body grinder ala M. Linquist style or go and razor sharpen all my bowl turning tools and go at it methodicly with precision instruments and either screw the blank up or end up with something that I can start at 180 grit and either scenario is as likely as the next.

 

[gkulibert]

Most problems sanding bowls are related to sanding endgrain. This is true on both the inside and outside. You need to support the fibers to sand off the endgrain. I apply a wax-turpentine mix to the endgrain and then sand with a course grit sandpaper. When the wax is about gone, so are the endgrain problems. If not apply wax a second time. This trick had reduced my bowl sanding time by 50% or better. you can hand sand or use any of the powered sanders. The wax-turp mix is about 50-50 by volume. Any wax will do, cheap canning wax works fine. If the mix is too stiff add more turp.

 

[pencheff]

Wax and then what finish?

I apply a wax-turpentine mix to the endgrain and then sand with a course grit sandpaper. When the wax is about gone, so are the endgrain problems.

What finish do you use after introducing wax to the raw wood? Doesn't this preclude using a film building finish like lacquer or polyurethane?

 

[Gary]

I apply a heavy coat of shellac to the areas of end grain; Go sharpen my gouge while it dries, then take a finish cut --- usually the tear-out and the shellac is all gone.

(A local turner told me that whatever I was going to use for the final finish could be applied to the areas of tear-out to support the fibers, and then a sharp gouge and a light touch would do the rest)

It Works

 

[KenN]

TurningDog,

For all those examples and more! I learned that lesson way back when I was learning to hand-cut dovetails. I was blessed with two old masters who generously shared anything I needed. One of them began his instruction with "The tails must be cut first - cut the pins first and disaster will follow". The other began: "The pins must be cut first - cut the tails first and disaster will follow". Each of them made absotutely beautiful dovetails and I could come close using both methods. Needless to say, my only comment to both of them was, "Thank you!!!". I doubt either knew they were passing on a second valuable lesson.

Dogma in any guise is curious. A re-read of Aesop's "The Man, the Boy and the Donkey" is instructive.