high humidity woodturners unite!

[Greg Thomas]

I live in Northwest Arkansas in the Ozarks, about 1300 feet elevation. We normally have a moderate climate but this year we're having a very hot and humid summer and my normal drying technique for green turned bowls is not working. I usually wax and store my greenturned bowls on shelves in the dark back wall of my studio and forget about them for a month or two, then I may change the shelf level, putting the ones that have lost the most weight on a higher shelf.
This year after only a day or two, I'm having to scrape off rapidly growing mold. I now have a fan blowing on the area and hope that helps. Any other suggestions?

 

[Ed_McDonnell]

1) Learn to love spalted wood

or

2) Adopt a different drying technique. I microwave a lot of wood to either allow me to finish it within a day or two of roughing or to at least reduce the moisture to a point where I won't start a fungus farm on the drying rack.

If it's really humid you might want to rethink the wax. In South Florida (where it's only really humid on days that end in "y") I found wax coating (anchorseal type stuff) to be a fungus accelerant. I coated a couple mahogany logs that I wasn't going to be able to get to for about 6 months. It's the only time I've had mahogany spalt and rot in my shop.

or

3) Hose down the area with fungicides on a regular basis. It's cheaper, easier and a whole lot safer to learn to love spalted wood.

Ed

 

[MichaelMouse]

Mildew. Two kinds that I'm familiar with. One is white or greenish and hairy, the other ugly black and penetrating. The white stuff is ugly, maybe a bit of trouble to the sensitive, but otherwise superficial. The black stuff can get in far enough to mess up nice white wood.

You say you waxed them. Not on the inside, please. The drying process mechanically closes any checks that might form there. Outside endgrain is generally OK, but as you noticed, the real problem is the race is between checking and mildew. Go over to Wally World and get a hygrometer. If you're 65% or more RH, don't bother to wax. Anything other than the broadest bottom or steepest walls should suffer no real harm. At least that's the way things work for me.

I dehumidify my shop to 50% RH in the summer. Winter gets closer to 30. Not a problem with turning, but flatwork like frame and panel wants to be tight in the summer, looser in the winter.

 

[glenkey]

I'm not that far from you, not the same elevation. I have gone to using newspaper.
After roughing out, I use two full sheets of fishwrap and tape it closed with masking tape. Let them sit for a month or more and when I open the paper, all is dried ready to finish turning.
You can also find cheap built kilns on the web. Using an old freezer with a couple of holes drilled in, one on top one on the door towards the bottom. Make a damper out of some plywood. Place a 60W light bulb, incandesant, in the bottom for a heat source and you have a small kiln.
Good luck.

 

[Richard Baker]

Greg,

What kind(s) of wood? Have had the black mildew on hackberry under wax. Some turns off and some penetrates. Also a wet and humid spring here with RH to 70+% in the shop when the A/C was off.

 

[john lucas]

I'm in Tennessee and boy is it humid. I get sweaty just walking to the car. I dry my rough turned bowls by sealing the end grain areas with anchor seal and then putting them in paper sacks for the first month. I have very little or no mold. My shop (2 car garage) is mildly airconditioned with a room airconditioner that is way too small. I don't leave it on all the time because it's simply too expensive and I can't be in the shop every day. Maybe it takes out just enough humidity on the days that I do run it to keep the mold down.
In my last shop I ran a dehumidifier. It did remove the moisture but really added a lot of heat to the shop. I suppose you could exhaust the heat outside somehow. It easily pulled over a gallon a day from my old shop. I had serious mold problems in that shop. It was a basement shop and actually leaked when it rained. I had to install the dehumidifier just to keep the tools from rusting.

 

[glenkey]

John, like you my shop is in the garage. Also like you I have a small room AC that barely cools the shop. When turning I have a box fan that blows toward the lathe. It helps, some. The size of the windows in the garage limits me to the size of AC that can be installed, soooo I tend to add to the humidity in the shop. Then when spraying finish, the door is open and all the cool goes out and the heat and humidity comes in.
Gotta love it, God is the only one that can control it.

 

[glenkey]

Greg here is a site that has a simple kiln you can make. I described it in one of my post.
http://azwoodturners.org/kiln.pdf

 

[Greg Thomas]

Mold problem

Thanks everyone, I really appreciate all the suggestions and plan to give them all a try. I have a set of shelves in the far end of my studio, the cool dark end where I set my green turned bowls to dry. I now have a small fan blowing on those shelves and the air circulation seems to have stopped further mold.
I will definitely be trying some of the techniques suggested to speed up the drying time as I have a commission to turn a burly old red maple into at least a hundred bowls. This forum is really a good resource.

 

[n7bsn]

Oh, you are whinning about high humidity and high temps.... locally, something we don't have to get too worried about.

When it gets warm here, it gets warm cause the weather is coming from were it's dry. So warm temperatures results in lower humidity.

Of course, come the other 10 months a year, the weather comes in off the Pacific, while it is very damp (300 over-cast days a year), it's also not warm

Around here, if it doesn't mold, it's cause it's corroding.

Almost any wood, you care to mention, will be moldy.

We just try to keep the wood dry, although old wood, say stored in an un-heated building for years, will still be slightly spated, after a few years

TTFN
Ralph

 

[Mr. Don]

humidity

Hey, Ralph of wetter Washington...ya furgut one minor thing....MOSS!! If it does not rot or mildew, it will turn green with MOSS!! Does not even have to be wood...just look at those "white" plastic fences. A little more on the topic, I have problems with Holly and Madrone getting those black spots. This is after boiling, without boiling, waxing and not, air drying, etc. Have tossed many bowl blanks and other cuts of both woods because of this. I have tried bleach, detergents, vinegar, etc., and nothing helps. This damn stuff goes deep into wood, and ruins an otherwise fine piece. Any help would be greatly appreciated.😕😕

 

[Jake Debski]

Like MM, I depend on a dehumidifier in my basement shop. Between the fact that the basement is naturally cooler and the dehumidifier it is the most comfortable place to be on hot humid days. A dehumidifier is also much less expensive to run that an air conditioner. An added benefit is the metal surfaces of my tools are far less prone to rust.

 

[n7bsn]

Sorry Mr Don, for some reason I get no black-spot mold in either Holly or Madrone. Maple and Alder, well.... then I make it a design feature

 

[Robert Manning]

I wonder if salt could be used in some way.

An old friend of mine has a wood pirate ship in Cabo San Lucas on the tip of Baja, Mexico. The Sunderland was built in England in the 1880's. He keeps the deck from rotting by drenching it with saltwater daily. The deck was replaced at some point, but I believe the hull planking is the original 3.25" thick by 5.25" wide oak. The Sunderland is eighty feet long at the waterline with a twenty foot beam amidships. She has two cannons which are fired with black powder on each cruise. http://www.youtube.com/watch?v=XNszTFnn_Gk&feature=related

 

[MichaelMouse]

I wonder if salt could be used in some way.

It would certainly slow the drying process if you infused it with salt. Not to mention the problems encountered with CaCl2, a common component in rock salt which is even more hygroscopic than NaCl. Keeps the dust down out on my road pretty well.