mold

[roger wiegand]

I used to turn a fair amount, mostly spindle work for furniture and almost always dry wood. I'm getting back to it now and recently had a great tutorial on bowl turning in green wood. In my enthusiasm I made up about 30 bowl blanks from cherry and apple trees that came down recently, bandsawed them to rough circles and coated with Armorseal. I've been roughing out a couple of them a day, putting them into paper bags with fresh shavings to dry for final turning and finishing.

Both my stash of blanks and the rough turned bowls are growing enormous fur coats of mold, over the course of about a week. Looks like mostly Neurospora with some Aspergillus, so just garden variety stuff so far. I'm not very worried about it from a health point of view. I am concerned about what it will do to the wood and what it says about my drying conditions. I know I want them to dry slowly to avoid cracking, but is this too slow?

Is this a problem, or just par for the course? Both the wood and shavings are quite wet. The apple, in particular, has so much water you'd think it had come from a submerged log. I've thought about dunking them in a bleach solution to slow the mold down, but also wonder if I should let them air dry more before packing them away.

Your thoughts will be appreciated.

[Grant Wilkinson]

There are numerous articles on drying green rough turned bowls that may help you, but I would strongly suggest getting rid of the wet shavings. They are holding moisture in, not letting it slowly out, and the extremely humid environment you are creating in the bag is giving rise to the mold.

[Michael Mills]

I agree with Grant to get rid of the wet shavings. I don't think you need to dunk them in bleach. About a 25% mix in a spray bottle and a good spritz should take care of it; I may be wrong but I think mold is just surface.

A lot of folks do cut into blanks to start with but I leave mine in half-log form and coat the endgrain (twice) with Anchorseal. I just put them on a rack, no bags until I rough turn them.
I leave extra length in case cracks do occur; I have about 4" total I can trim off back to good wood. If turned into round blanks and cracking does occur it will decrease the size of the blank. Turning them round to start with also may negate the possibility of using it for spindle work (candle sticks, etc) in case you change your mind about the use.

[Jeffrey J Smith]

I agree - get rid of the shavings. Rather than bagging, I sticker-stack them in the crawlspace under the shop. its about 5' to the floorboards with good cross ventilation. the ground is covered with plastic sheeting. Here in the very wet Northwest, it works well for most woods.
I've found that using chloine bleach on mold is only a temporary cure - once the water evaporates the chlorine is largely ineffective. Kills the mold, but its prone to return. A weak dilution of boric acid works better for me. Once the water has dried it leaves behind a very light coating of boric acid that keeps mold at bay for a very long time. It doesn't seem to penetrate the surface to any great extent. When ready to turn, I give the blanks a quick dunk in the horse trough used to store stuff I haven't gotten to yet, wipe it mostly dry and put it on the lathe.

[John K Jordan]

I do know some people who bury the blanks in a pile of shavings but not in a bag with shavings. Perhaps the shavings in a pile on the floor dry quickly enough to prevent the mold. Probably you would be better off air drying the rough turnings for a least a couple of days before bagging.

I don't bag but coat the rough-turned bowl with anchor seal on the outside, at least on the end grain, before drying it in the air on a wire shelf. I've never had any mold. My shop has heat and air if that makes a difference. I wonder if your shop is too humid and warm. Also, mold spores are everywhere but if you are getting mold on the outside of all the Anchorsealed blanks I wonder if you somehow have an abundance of spores in your shop, perhaps brought in with the wood and propagating on the blanks and bowls.

BTW, I do use chlorine bleach to treat mold and algae around the farm. I found out that full strength laundry bleach doesn't work as well as bleach diluted about 1/2 with water. I don't know why.

If conditions are right to grow mold on the outside I suspect fungi is also growing inside the wood. This can cause beautiful spalting or destructive rot, depending on how long it stays damp. If I had your mold problem I think I would take all the blanks and rough turned bowls outside and hose and brush the mold off, dip, spray, or brush on bleach water, then let them air dry to the touch before bagging.

And yes, wet wood can be dripping wet with free water which can sling everywhere! One trick some sawmill people do is to stand the logs (or slabs) on end for a while. This is more effective with some species than others. When I've done this a puddle of water collects under the end! (Doesn't do a thing for the bound water.)

Also, I just wrote about this in another message but some turning experts recommend to curb the enthusiasm when acquiring green wood! The other John Jordan says he always keeps the wood outside in log form, off the ground, never seals the ends. When ready to make a piece he cuts off about 6" and throws it away then cuts a single blank to turn immediately. The wood in the log will stay in good shape for a very long time. Another trick he uses to remove free water for faster drying is to blow it out with compressed air. Since he primarily turns hollow forms this is easy - put the air nozzle in the opening and seal with the fingers - the water will bubble out the sides.

JKJ

[roger wiegand]

Thanks all, I'll ditch the shavings and see what happens. It's only firewood after all, if it cracks it's not a big deal-- there's lots more and I need the practice! The fellow who taught me told me that a paper bag and shavings was what to do.

I haven't turned the heat on yet, so the shop is basically ambient conditions, though it seems to warm up with the sun and in the fall/winter stay 5-15 degrees warmer than outside on its own, similarly cooler in the summer (it's pretty well insulated with lots of south and west facing windows and a big oak that shades the windows in the summer). There's no source of humidity other than me and the green logs.

I got quite the shower while turning the apple-- on subsequent pieces I just let it spin for a while until the shower subsided.

[Thom Sturgill]

According to several professionals I talked to the main thing to prevent cracking is still air. The shavings create that, but so can a lot of other things. A draft will cause one side to dry faster and create stresses that cause cracks. Anchorsealing the endgrain is a good protection where you have moving air. Here in Florida, some of us use plastic bags for rough-outs, but you have to take it out every day and reverse the bag so the collected moisure can evaporate. That's a lot of work if you are processing a large number of blanks. Turning green to final thickness also works to speed drying and prevent cracks as the wood can (and will) move.

[Wes Ramsey]

I agree - get rid of the shavings. Rather than bagging, I sticker-stack them in the crawlspace under the shop. its about 5' to the floorboards with good cross ventilation. the ground is covered with plastic sheeting. Here in the very wet Northwest, it works well for most woods.
I've found that using chloine bleach on mold is only a temporary cure - once the water evaporates the chlorine is largely ineffective. Kills the mold, but its prone to return. A weak dilution of boric acid works better for me. Once the water has dried it leaves behind a very light coating of boric acid that keeps mold at bay for a very long time. It doesn't seem to penetrate the surface to any great extent. When ready to turn, I give the blanks a quick dunk in the horse trough used to store stuff I haven't gotten to yet, wipe it mostly dry and put it on the lathe.

Here's a tidbit I learned from my bro-in-law that owns a fire/mold restoration and cleaning business. Bleach is one of the more effective ways to kill mold, but only what it actually comes into contact with. If the conditions that caused the mold to start growing in the first place don't change it will return with friends. When bleach dries it actually becomes food for the mold that you didn't kill, so by applying bleach you're actually inviting more mold to grow. According to him the most effective method for getting rid of mold is dish detergent and a good scrubbing and drying. That is the only thing they use for cleaning houses with mold damage - tear off everything down to the studs, clean, dry, then monitor before rebuilding the walls.

[Perry Hilbert Jr]

when I was in jr high school, the science teacher had a tough steel container and a vacuum pump. He could put something damp in it and turn on the pump. After a bit, the piece of wood was dry as a bone. Anybody use/tried this method.

[Chris Gunsolley]

when I was in jr high school, the science teacher had a tough steel container and a vacuum pump. He could put something damp in it and turn on the pump. After a bit, the piece of wood was dry as a bone. Anybody use/tried this method.

So it just sucked the moisture right out, huh? What I like about that is that it wouldn't require heat.

I suppose you could make something similar with a dust collector. Could you give more details on the compartment that the object went into? Did it have a screen or something inside to keep it in place instead of having it sucked up toward the vacuum hole and banged against the top?

[Bob Bouis]

Vacuum drying works by lowering the boiling point of water until it boils away at low temperatures. You need pretty serious vacuum for that, more than a dust collector could do.

Also, contrary to what you might have seen on TV, vacuum doesn't suck solid objects up through little holes. Heh.

[Prashun Patel]

You meant anchor seal, right? Not armrseal.

I coat with anchorseal but do not bag. If I start seeing mold, I put the waxed rough out in the sun for a while.

I don't like storing rounds, only rough turned bowls.

It's only partially a science. I find I have to watch my stock the first month or two.

[Bob Bouis]

If you want to prevent mold, use anchorseal and, before application, add a fungicide or mildewcide to it. You can use lawn fungicide (propiconazole, chlorothalonil) or certain algaecides or mildewcides intended to be used as paint additives. Many of these are safe enough to be used on food, swimming pools, or even in cosmetics.

Better to get the concentrated stuff so its carrier doesn't water down the anchorseal.

[roger wiegand]

Yes, I meant Anchor Seal. :D

I took the roughed out bowls out of the shavings and the mold pretty quickly receded. All of the apple bowls promptly cracked (within 36 hours), the cherry ones are doing fine. I didn't Anchor Seal the roughed out bowls, I'll try that with the couple pieces of apple log I have left.

The bowl blanks don't include the pith, but I'm pretty close, so perhaps they are just too unstable.