sanding makes it out of round

[Mike Minto]

you guys have a solution to sanding a piece of wood which has spots that are softer than the rest, resulting in a formerly round piece becoming out of round? happened to me this weekend - thought i'd fixed it by re-turning, but when sanding happened again. not very noticeable, but you can feel it and i know it's there.

[Michael Mills]

The only things I can suggest are;
Use a very light touch with the sandpaper, or
Sand the area by hand, or
Apply a couple to coats of sanding sealer (shellac, or lacquer) to "harden up" the soft wood. I cut standard shellac with two parts DNA.
Mike

[alex carey]

light touch slow speed.

[Michael E. Thompson]

The wood is likely heating up too much as you sand and causing it to warp. I used to have the same issue, I did as other have said, slow and light touch, and the out of round was eliminated or greatly reduced.

Mike

[Jeff Nicol]

Mike, With some woods that have a great difference in the early and late wood in color and density this will happen. Lots of the pine and fir trees will do this. I find on Tamarack it will do it very easily. What works the best for me is to speed up the lathe and us a light touch as not to create any heat and use new sandpaper. Also if you are hand sanding I would reccomend a sanding block that has a little padding but keeps the paper on the same plane so it does not dig down into the softer grain. If I am power sanding I go up to a larger (3" or bigger) disc to do the same thing. If you are using your hand, the fingers create separate pressure points and that will sand deeper in the softer wood. The suggestion to stiffen up the wood with shellac or lacquer is a good thing too.

Hope this helps,

Jeff

[Rick Prosser]

not very noticeable, but you can feel it and i know it's thereWell, we are dealing with wood here, and as much as we try to achieve perfection - it is wood, and it will change.:(

The methods already mentioned can make the best of the situation, but we have to choose where to draw the line and call it done;)

[curtis rosche]

if you set up a jig that only lets a sanding block go so far against the bowl, its a little hard to do but for small spots it works. then it will take down the soft spot first but it has to take down the rest

[Steve Harder]

and trying to clean up tool marks and tearout as best you can before starting to sand can also help.

[Fred Perreault]

I think that the bowl is probably becoming oval as you work it. I have this happen some times. Between the heat buildup, the drying, and the inherent stress in the wood, it is likely the wood is moving. Usually, sanding will reveal the difference between the softer and harder grain by providing an uneven, kind of rippled effect. But sanding isn't likely going to make the object oval. Use a good measuring device the next time this occurs, and you will surely find the bowl is out of round, and probably still of the uniform thickness you had when you started sanding.... at least I think you will :)

[alex carey]

i actually dislike sanding blocks and instead I use a dish sponge.

[Jon McElwain]

I've had some luck with plumbers tape. Norton makes some 1" wide sanding strips that I cut about 12" long and hold to the form as it turns. Speed it up and hold the paper so that it contacts as much of the surface as possible. The tape seems to ride over variances this way.

[Barry Elder]

Buy an 8 or 16 oz bottle of Super Glue, apply liberally to bowl after protecting lathe, and let cure. (Not recommended if you are sensitive to the odors of super glue when it fires off.)