Mold during drying process?

[Charlie Harley]

Another new guy question...

I was taught to dry rough turned green wood by putting it in a paper bag with some shavings and fold over the bag. This has worked really well for several bowls, but then this past weekend I had a hiccup.

I rough turned a few bowls from spalted maple a few weeks ago, then bagged them shavings. Sunday I checked them and the surface had a green layer forming that looked like mold.

First, how do I get rid of this mold? I scrubbed it with a bleach/water mix and let it dry hoping this would kill any spores. Any other suggestions?

Second, what can I do to prevent it from happening again?

All help is gladly accepted.

 

[dkulze]

Hey Charlie,

Well, the answer to your hiccup is right in your description. Spalted wood is wood that has begun the rotting process and is dead throughout the spalted area. The spalting itself is caused by molds and fungi, hence the tendancy for the piece to mold rapidly if sealed from drying in any way. I don't know of any specific ways to prevent this but spraying down with bleach before bagging may reduce the molding somewhat. Also, letting it dry just a little before bagging might help, since the mold requires relatively high moisture to grow.

For what it's worth, really spalted wood tends to crack less when drying cause it's already lost alot of it's structural integrity.

dietrich

 

[Steve Worcester]

With the right humidity levels, it is going to continue to grow as diet said.
It is mold, it won't hurt anything (unless snorted) but what I would suggest is if you want to dry it, don't put the shavings in the bag. Let areas to trap moisture will lower the humidity level and the grocery bag will start to allow it to dry.

 

[MichaelMouse]

You're probably dealing with apples and oranges. The spalt is produced above 18% MC, and is a fungus which feeds on lignin, thus the weakening of the structure. The fuzz is likely mildew, another critter which will flourish at lower moisture content, but which probably gained a boost by your centrifuging the unbound water to the surface. Dollars to donuts it's only on the outside end grain, unless those shavings were pretty wet. Even there you have two varieties, black mildew which makes ugly spots and can run into the grain pretty far - the reason I don't use anchorseal, and white mildew which has long external white or possibly greenish filamentous aspect.

I take advantage of the known, that wood doesn't start to collapse and check on the surface until it's below ~30% moisture content by weight, and let the visible moisture evaporate before placing the piece into any kind of humidity controlled environment. For me it's in an isolated part of the basement, close to the moist concrete, others use bags or other forms of microenvironment control. Usually pretty obvious where the water is by the darker color. Let it fade so the end grain is more or less the same color as the face grain before sequestering, and mildewing should be minimal and shallow. If you've got a relatively porous wood, you can blast some of the moisture out with compressed air from the inside and save a day or two on drying, while minimizing mildew. In any case, one control measure at a time seems to work best. Going with two slows loss so much that the mildew begins, even under the anchorseal, because the spores are everywhere.

If you use shavings in a bag, use dry shavings. They'll adsorb up to 30%, as will the cellulose in the bag, and control the loss from there on. To hurry, if you're in a hurry, change the damp bag and or shavings for fresh after a couple of days.