sanding irregular peices with holes and edges

[jcooper]

the other day i attempted to durn some spalted maple that was rectagular, i turned the bowl with ease while keeping the rectangular shape, but when it came to sanding the inside and out i could not do it. scince there were open spaces in the bowl (similar to what happens when you turn burls and holes develop, or you are trying to retain a natural edge that is thus uneven). so when i sanded (by hand with lathe on) the paper just got batted around, sneaking into the open spaces and never really accomplishing anything. i couldnt get a smooth finish by any means possible.
any sugestions for sanding irregular pieces? i really like the look of having holes and natural edges, but i cant sand it for the life of me. any suggestions are greatly appreciated

 

[john lucas]

I sand my natural edge bowls by holding the bowl still on the lathe and then power sanding with the drill. If you don't have indexing(which I don't right now) Use a weighted strap or a bungee cord that runs across the chuck or faceplate. This will hold it still fairly well and you can sand it. I did use one of those thick black rubber bungee's that I picked up off the rode but it broke not long ago and I haven't replaced it yet. The thinner bungee cords don't hold the chuck as well.
I can power sand with the lathe on using the drill but I have hundreds of hours doing this. It's very hard to do it without making one edge thin or setting up vibrations which can show up in the sanding. Except for my production mirrors I now sand all odd shaped pieces with the lathe off.

 

[MichaelMouse]

I know this will come as a surprise to many, given my utterly conventional approach to turning, but I don't sand the way most folks do. I use a flexible shaft and Power Lock disks. Allows me to support the shaft handle on my toolrest as if it were a scraper, and apply the semi-rigid disks to the spinning work. Doesn't much mind spaces, sands the places, and since I hardly ever press, doesn't round over the edges.

You can use velcro stuff, which I do as well, but it's not as useful as the Power-Locks on interrupted edges. Paper crimps at times. Full edge, works great. Always with the softer velcro when sanding lathe off, but even here the handle gives better control for me than trying to maneuver a drill motor. I can even take a piece off the lathe, hold between my knees, and sand. http://www.leevalley.com/wood/page.aspx?c=2&p=31030&cat=1,130,43409 is one source. I power mine with an induction-run FHP 1725 motor. Low noise, good control, a tough combination to beat.

 

[Mark Mandell]

For primary sanding I, too, use Power-locs (get mine from Packard). If the piece has voids that I choose not to fill, I'll guage the disk to the bowl surface using one of several curved tool rests that best match the curve. Same thing on the outside curve. I use a 2,500 rpm Sioux angle drill and just let the abrasive kiss the surface at between 80 and 110 degrees to the rotation

After primary sanding with 120 and 150 [larger grit for tear-out situations] I'll often turn the lathe by hand and go with soft hook/loop paper with a feathered edge from 180 on up. Again, the key is to just kiss the surface with the abrasive so that the grit cuts but doesn't dig more grooves and such in the wood.

M

 

[hockenbery]

I sand my irregular pieces off the lathe. I try to get a real good tool surface.
Most of my work is with green wood so I let the turned piece dry for 2-3 days.

If I were sanding on the lathe I would do as John mentioned and not run the lathe. It is very difficult to sand irregular pieces under power and keep the walls an even thickness.

I use 3" or 2" velcro discs in an angle drill and hold the piece in my lap I start with the highest grit that removes the tool marks. I may sand a particular region with a lower grit if the area needs more sanding. I can also keep the sanding scratches in line with the grain and in the domestic hardwoods I seldom sand beyond 320 ont he bare wood.

Happy turning,
AL

 

[Steve Worcester]

Doing square work isn't a whole lot different, but a catch on the corner with your hand can be real ugly.

I do it two ways, either strips wrapped around some high density foam (like used to package computers) or the same power sanding method described above. I just use hook and loop disks though.

 

[MichaelMouse]

Putting this here, because it's a similar circumstance to sanding interrupted turnings. Turning highly spalted wood with big differences in resistance might as well be interrupted. The attached shows a truly nasty soft piece of rotted birch done as above.

However ... this morning I went down to the basement to clean up a bit, and picked it up to put on the "waiting" shelf. There it was, the big scrape that I had somehow missed last night, too close to bedtime. Nothing daunted, I pulled out some paper and began to sand carefully across the torn area. No effect. Then I looked again, and noticed that the torn area was slanted and discontinuous. Dropped 3/8 of an inch from the rim in about 4 inches of run, something nearly impossible to do - move a gouge in that fast with the piece spinning at 680. Swirled around the irregularities in the grain, and followed the annual ring. It was a natural!

Problem is, the eye is drawn inexorably to it, and it looks like a rip. The bowl is probably unsaleable. Surface is nice and even to the fingers, though. Eleven by five.

 

[Russ Fairfield]

I know this will come as a surprise to many, given my utterly conventional approach to turning, but I don't sand the way most folks do. I use a flexible shaft and Power Lock disks. Allows me to support the shaft handle on my toolrest as if it were a scraper, and apply the semi-rigid disks to the spinning work. Doesn't much mind spaces, sands the places, and since I hardly ever press, doesn't round over the edges.

Mr. Mouse, whoever you are, this might work for you; but it is a recipe for a disaster in the hands of an INexperienced woodturner. Some methods for doing things are best left behind the closed doors of our own shop.

(CORRECTED ERROR)

 

[MichaelMouse]

Keeps my hands safely out of the way!

Have you tried it?

 

[Steve Worcester]

Mr. Mouse, whoever you are, this might work for you...

(He called you Mister)

In reading over your technique again mouse, I think that the issue with the process you describe is the possibility that you would have a sander catch and with it resting on the toolpost, all hell can break loose.

 

[Mark Mandell]

(He called you Mister)

In reading over your technique again mouse, I think that the issue with the process you describe is the possibility that you would have a sander catch and with it resting on the toolpost, all hell can break loose.

Steve, with the piece rotating counterclockwise and the disk making contact between about 3 and 5 o'clock, the wood is rising past the tool rest so it's impossible to have a catch. You could, I suppose, jam the disk into the wood to get it caught in the passing void resulting in the whole deal getting wrapped up on the lathe.

I use this technique with an angle-head drill. I rather doubt I'd use a flex-shaft unit; I'd be concerned with the shaft getting hit by the rim at 9 o'clock or so.

M

 

[MichaelMouse]

(He called you Mister)

In reading over your technique again mouse, I think that the issue with the process you describe is the possibility that you would have a sander catch and with it resting on the toolpost, all hell can break loose.

Actually, Mr. Steve, less than the danger of doing so with a gouge. Not only are you supported on the rest, with the leverage gained by holding the handle on the other side of the fulcrum, but you have a flexible edge, so if you advance it a bit too fast into the spinning shadow, it'll smack your hand rather than grab away as a rigid collision would. It's a broad "gouge" but it'll bend. Much rather have the third very steady hand provided by the rest than wrestle a drill that I'd have to support freehand on a rotating piece. I'm not as strong as that rest, and I can maneuver into a lot smaller space that I ever could with a drill.

You do, of course use the card of a different color method to highlight what's poorly seen, and as the best sanding is that which presses least, you just follow the contour with the edge of the disk hardly bending on the inside. I like to use the center portions of the disk on the outside, so as to even the usage. Disks last several pieces at 150, fewer at 240, and maybe twice at 320, but the edges don't round, and the hands are behind the rest.

Additional advantages include better preservation of the original shape, since the paper is not riding the wood, which is a great thing on white-rotted pieces like the one above in this thread, as well as the ability to bridge gaps, the original subject.