How to stop mildew

[Steven Forrest]

Folks,

I have a bunch of green bay laurel that keeps sprouting mildew/fungus. I have cut it back twice, and two days later, it's forming again. I had originally sprayed the blanks with household bleach or peroxide, and neither made a dent. In the past, cutting away the mildew was enough, but not this batch. Suggestions to treat and/or prevent fungal overgrowth on green wood? I am in Sonoma County - it's fairly damp this winter. The wood is in my garage - dry, but ambient humidity is basically the same as outdoors. Nothing is stacked - plenty of air around it. Nothing is wrapped in a bag. Still come the fungi. I did boil the wood - wondering if that somehow promotes fungal growth. Help!

 

[John K Jordan]

Suggestions to treat and/or prevent fungal overgrowth on green wood?

Don't know anything about the laurel, but I've had problems with grey stain in light woods like Holly and maple - was told it was from a fungus. For Holly, the advice I got probably won't help where you live but it's to cut the tree in the dead of winter then dry aggressively.

For boards this usually means kiln drying but I'm generally able to keep Holly white if I seal it immediately after cutting it up with the bandsaw, unless the logs got too warm when stored outside for a while - I dry inside the shop in the AC when it's warm. I don't remember anything about boiling "causing" fungal growth, I wonder if the fungus was already in the tree when it was cut, or if it gets into the wood through the cut surface. Is it sealed well? Would it help to disinfect the saw chain?

Do you have the same problem with other species?

Are you boiling the log section? I think the advice I read was to boil an hour or so per inch of wood when boiling roughed out bowls but this was to minimize cracking and distortion. I can check my notes and books.

If I see fungal growth on the outside of the wood it is usually headed toward spalting, which can be a plus sometimes. The tricky thing about spalting on purpose seems to be catching it at the right time before it rots!

About bleach, a scientist friend once told that contrary to what I assumed, bleach was more effective against mold and mildew if it was diluted with water, about 1/2 and 1/2 if I remember. I can ask her again to verify when she gets back but won't be until after New Year's.

JKJ

 

[Richard Coers]

Household bleach has a high water content. Buy some 2 part wood bleach.

 

[Isaac Fisher]

I would skip the bleach and eoughspend a day roughing things out.

 

[Steven Forrest]

Responses so far:
First of all, I certainly appreciate the advice/attention.
John: I don't think this is spalting stuff. I think it's staining stuff - ugly, blotchy grey. It is dead of winter (for us). I have had this happen with other species, but this is an especially heavy attack. I don't know that I can sort out source - ambient, chain, etc. I forget if I roughed out first or after boiling, but I did boil the wood, then applied bleach/peroxide, then watched it grow over a couple of weeks. Have now cut back twice and it's still regrowing in 2 days. Someone said the hyphae (sp?) may already be all through the wood, in which case, it ain't going away as long as the conditions favor it growing. And those conditions are wet wood, cold, high humidity, and low air flow.
Richard, I do have some two part bleach. I was sort of hoping not to have to go that far, but I guess that's my next move.
Isaac, stuff is all thoroughly roughed. These are not pieces I'm turning to final finish green.
I haven't tried microwaving these. I suppose that could be another path, but I'm not sure they'd get down to dry enough to frustrate the fungus quickly enough to beat the staining, or still avoid cracking.

Still listening. Thanks, all.

 

[Mark Jundanian]

I wonder if kiln drying could stop the cycle you're seeing? Do you know anyone with one? just spit balling

 

[Joe Kaufman]

Could it be a reaction resulting from of the material of the container in which you boiled the wood?

 

[Mike Novak]

I used oxyclean on a deck that had persistent mildew problems. Worked good, lasted longer than bleach. I think about a cup of oxy to a gallon of water? You could even make a paste.

 

[Walter Mooney]

I think it was Mike Mahoney who told our club some years ago that to at least minimize or at best eliminate mildew when drying roughed-out bowls and such, sprinkle some boric acid in the bag (brown paper bag) with the bowl before closing it up. I can attest that it works (at least for me it does). YMMV. Best of luck Steven

 

[John K Jordan]

Household bleach has a high water content. Buy some 2 part wood bleach.

I thought 2-part wood bleach was intended to lighten wood surfaces.

And those conditions are wet wood, cold, high humidity, and low air flow.

How cold is cold where you live? And how humid?

Here it’s usually around 33-40 in the winter, occasionally down in the 20’s and up to mid 40s.
I keep all processed wood blanks in the shop, sealed, with the temp about 65. The humidity is low year around.
I’m wondering if high humidity might be a problem.

When given the choice I like to cut holly when it’s freezing outside, process inside and seal it immediately and air dry.
if I store it outside or in a unconditioned space it always gets grey stain. But if I turn something from grey-stained holly the 2-part bleach makes the turned surface white. Maple and holly boards/slabs cut on the sawmill and stickered outside to air dry when it’s warm and humid - hopeless.

For rough-turned bowls some people make a simple “refrigerator” or “freezer” kiln, an insulated box warmed by a light bulb or two inside and with holes cut for vents. There should be information on these on the net.

Maybe there is some accessible research out there on fungi which could help. Sari Robinson (Dr Spalt) has done a lot of research on fungi. When I get some time I try do dig through her books. She focuses on inducing fungal growth but probably knows what inhibits it. But it might be able until next week.

Spalted Wood: The History, Science, and Art of a Unique Material​

Spalting 101: The Ultimate Guide to Coloring Wood with Fungi​

Might even be able to contact her and ask. Some people here know her personally

JKJ