Sanding problem

[Mike Minto]

I'm working on a small rice bowl about 5 inches across, finishing a green turned spalted oak piece to do so. I was just about done sanding, had put on a seal coat of shellac (which I intend to finish the bowl with as well) and went to do the finish sand. Started 100, ending 220. As the piece rotated, I saw the dirty grain I hope you can see in the photos. Can the spalting spread as it is sanded? Is it a loose material, not just a coloring of some of the wood? I can't figure out what happened. The small foot will be removed when the bowl is complete. Any help would be appreciated. Mike

[Steve Schlumpf]

Mike - looks like a very nice bowl to me! Great form and really pretty wood! Guess I don't see the problem area. Was the wood discolored before you applied the shellac? Lots of woods have color variations that seem to become enhanced once they spalt. Like I said - from my vantage point - the bowl looks great!

[Mike Minto]

Steve, at first there was no discoloration in the grain. then, as sanding progressed, it just 'showed up'. i went ahead and put on the seal coat - possibly a mistake - I guess I'll just sand deeper, and hope the dirty color in the wood goes away before I sand thru the wood! Mike

[Bonnie Campbell]

My experience (which isn't extensive) is that the dark spalting (fungus) WILL transfer to spots of open grain. Did you wipe the bowl out good after sanding and before putting on the coat of shellac?

Though to be honest, I can't see the problem in the pictures. I think the bowl looks really good.

[Bernie Weishapl]

I agree with Bonnie. Sometimes it will transfer to the grain. I don't see a problem with yours. I wouldn't worry about it. Great looking piece.