Red Oak

[John C Bush]

A friend gave me a log of--best guess-- northern red oak(from the PNW). It's dense and heavy, turns nicely but rusts everything quickly and the freshly turned surfaces develope black spots in the pores and splotches randomly. Any arbor-o-chemists out there that can explain the science of this?? I'm used to the rust, but not this fast
and aggresive. Just wondering if the moisture from the wood is that acidic and what could be sprayed on the rough turnings to mitigate the black staining.Thanks, John

[Russell Nugent]

The tannins in oak will cause rust almost immediately. If you touch metal and the touch the peice of wet oak, you'll get black stains. I believe some people have had good luck using lemon juice to remove staining. A quick forum search will probably show several threads on this

[Richard Coers]

Russell is spot on. Tannic acid with water and steel makes iron oxide. Same thing as ebonizing oak with steel wool and vinegar solution. Mind your cleanliness with your hands. Lemon juice can remove the stain if it doesn't sit too long, but cleanliness works better.

[John C Bush]

Thanks, That was my first thought--thumb print was the noticable. I wear old welding gloves for rough turning so lots of Fe residue. I will give lemon juice a try.
.

[Don Stephan]

When working with steel woodturning tools, metal is constantly being worn away at the cutting edge. When turning wet wood, some of that metal dust will be trapped in the wet sawdust that accumulates in the flutes. Wipe the flute with a finger and metal dust on your finger, then when you touch the wet wood, black smudges. Took me an embarassingly long time to figure that out, and use an acid or other small brush to wipe the flute. Before handling a wet blank to reverse or take off the lathe now I wash my hands well.

In a recent Youtube video R Raffan put a piece of plastic film between a tenon and chuck to try to avoid black marks from the jaws. I haven't found thicker plastic film yet.

[Eugene Dixon]

.... I haven't found thicker plastic film yet.

Grocery bag? the heavy duty versions from The Kroger?