Some questions on spalted wood

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Forum topic by tyskkvinna posted 05-15-2010 11:13 PM 4202 views 1 time favorited 18 replies Add to Favorites Watch
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1310 posts in 2410 days

05-15-2010 11:13 PM

Topic tags/keywords: question

I have been noticing spalted wood here and there lately and was curious about it so I looked it up.. I have to say I’m amazed at the process of how wood becomes spalted .. nature is pretty impressive!

I would like to know.. does kiln drying definitely kill the fungi? Is there any visual difference to the wood before and after kiln drying – so that I could be sure the wood I am handling has been fired?

The reason I am asking this is because I have a very acute allergy to fungi. It makes woodworking kind of fun sometimes – I’ve had pieces develop a funk on them and I have to get rid of them, but this means I’m very attentive to my stock and make sure that I store it as properly as possible. If the wood has any active fungi in it there’s no way I could do anything with it.. especially anything that makes sawdust.

I tried some searching on the subject and couldn’t really find any info.

As a sidenote, sometime “soon” I am going to look into a wood kiln, and a side benefit would be things like this would be less of an issue. But in the meantime…

I’d like to work with some pretty woods and of course I’m not going to if there’s a chance I could get sick from it. But if it’s dead, it’s dead. I just don’t know how to tell.

-- Lis - Michigan - -

18 replies so far

View hazbro's profile


109 posts in 2414 days

#1 posted 05-15-2010 11:37 PM

you could spray boric acid, or a boric acid/glycol mix on any rough lumber you’re going to store before working.

-- measure once, keep cuttin' til it fits

View Div's profile


1653 posts in 2364 days

#2 posted 05-15-2010 11:44 PM

What I do know is that kiln drying and even air drying definitely stops the spalting process. So I would guess the fungi is dead! Spalting can only happen when,amongst other things the humidity is high enough. No moisture, no fungi! So now I wonder, if the fungi is dead, surely they can’t affect you?

-- Div @ the bottom end of Africa. "A woodworker's sharpest tool should be his mind."

View Gene Howe's profile

Gene Howe

8111 posts in 2853 days

#3 posted 05-16-2010 12:16 AM

I would think that dead or not, the spores would still be there.
I’m not allergic but, I can sure tell the difference in the smell when I’m resawing spalted maple, as opposed to non spalted maple.

-- Gene 'The true soldier fights not because he hates what is in front of him, but because he loves what is behind him.' G. K. Chesterton

View tyskkvinna's profile


1310 posts in 2410 days

#4 posted 05-16-2010 04:48 AM

I honestly have no idea if dead fungi would bother me or not.

I can try boric acid.. I usually have that, anyway.

-- Lis - Michigan - -

View yarydoc's profile


417 posts in 2569 days

#5 posted 05-16-2010 05:14 AM

Do you use a respirator? This is what I use and you can see all the applications it can be set up for.
A lot of different companies make these and they run from $25-$50.

-- Ray , Florence Alabama

View John Ormsby's profile

John Ormsby

1283 posts in 3161 days

#6 posted 05-16-2010 05:25 AM

I suggest you never mess with any spalted wood if you have an acute allergy to fungi. The spores will always be there and you never know when you will be exposed. You can expect a trip to the emergency room if things go bad. There is no guarantee of not being exposed to the spores even if you use a high quality respirator. The spores become air born and you can be exposed while cleaning up the wood dust after a day of messing with the spalted wood. I have heard of a few cases where a person has become ill for many months. It all depends on the conditions.
Your health is much more important than a certain type of wood. I am just trying to be careful in explaining the problems and dangers of spalted woods.

-- Oldworld, Fair Oaks, Ca

View hazbro's profile


109 posts in 2414 days

#7 posted 05-16-2010 05:50 AM

I also have allergies. hence the boric acid. I redid almost all of my insulation with Ultra touch (fireproofed with boric acid)....also repels ants and gnawing insects.

I set up my shop with an air cleaning unit and central vac.

This all came after I went to the emergency room in shock to get an epi-shot and an industrial dose of benedryl.

I am allergic to maple sawdust. And maple is my favorite wood. With dust collection, air filtration, and air movers I can sort of work with it.

On my shop shelves I have tools, and adrenaline shots.

EDIT: don’t forget your skin is your biggest organ. respirators only go so far. that’s why I cut questionable material in a man made hurricane. and then shower.

-- measure once, keep cuttin' til it fits

View Chris's profile


331 posts in 3510 days

#8 posted 05-16-2010 06:34 AM

This is the funny thing about spalted woods: they are the result of, as you already know, fungi which is developed by microscopic fungal spores known as hypha which float unseen all around us all the time. Especially amongst those of us whom reside in rural communities or anywhere there are large amounts of trees present. They are just floating around and being breathed in by persons when in these settings.

However i doubt the concentrations of hyphae exist in the air as they would there in a block of spalted wood. I had a conversation once with a microbiologist and was questioning him in regards to the dangers of spalted woods when being turned and the hyphae entering our moist lungs. Basically, it is simply more dangerous to work with any fine particulate wood sawdust as compared to spalted woods per se simply because all fine particulate matter is a carcinogen.

Furthermore hyphae utilize cellulose and lignin found in the woods cellular walls to decompose which we don’t possess within our lungs. so no worries there.

But the dust itself is reason enough to utilize a good quality respirator whenever turning woods of any capacity.

I would like to know.. does kiln drying definitely kill the fungi? Is there any visual difference to the wood before and after kiln drying – so that I could be sure the wood I am handling has been fired?_
now in regards to this question of yours i am not sure however i do understand that the temperatures reached in a kiln sterilze the woods within so the hyphae would be killed i do believe. Simply because the ideal germination temperature range for hypha to produce large amounts of hyphae is 70-90 degrees F.

So i think the correct answer to your question is yes the kiln would indeed kill the microscopic spores germination and activity but obviously they would still remain as allergens none the less.

I’ll tell you the US Forestry Service has some fantastic scientific documented case studies of kiln dried lumbers and the specifics on their website. You might want to delve into some of those readings some time, let me warn you ahead of time, roll up your sleeves for it is some fairly intense readings but great information.

Take care, Chris

-- Chris Harrell - custom callmaker "Quacky Calls" Eastern NC.

View Walnut_Weasel's profile


360 posts in 2646 days

#9 posted 05-17-2010 05:08 PM

Here is a blog on spalting that I have found. The author also writes blogs/articles for Fine Woodworking. I do not know exactly what degree she has, but she appears to be extremly knowledgeable in the scientific analysis of fungi. Note that she has several blog entries titled “I promise, spalted wood isn’t going to kill you.” If I recall correctly, in one of the blogs she does mention that if you are still concerned running the lumber through a kiln (or even your oven) will kill the fungi for good. Hope this helps.

-- James -

View tyskkvinna's profile


1310 posts in 2410 days

#10 posted 05-17-2010 05:30 PM

Hey, that blog is very helpful! I will be reading all of it.

But the dust itself is reason enough to utilize a good quality respirator whenever turning woods of any capacity.


Alas, my allergy is not strictly respiratory. It’s a contact allergy. (If I touch it) Of course, I use gloves and whatnot. And I have had an epi-pen for years. ;)

It’s going to be “a while” before I even consider actually working with spalted lumber, but I’d like to do my research as thoroughly as possible before even attempting it.

-- Lis - Michigan - -

View Nomad62's profile


726 posts in 2382 days

#11 posted 05-17-2010 05:34 PM

I agree with whaty John Ormsby said above, and add that while the heat will kill fungi, it is no guarantee it will kill it all; and that spalted wood will begin spalting very quickly once humidity conditions allow it to. I have read that spalting will occur at humidity percentages above 10; that means just about anywhere. If I were you, I would find other woods to work with.

-- Power tools put us ahead of the monkeys

View TopamaxSurvivor's profile


17577 posts in 3100 days

#12 posted 05-17-2010 08:32 PM

I have been told by my respiratory DR we all have a lot of spots in our lungs form various exposures through out our life times. Most of them will be benign, but occasionally a person will react to it. Growing up on a farm, the first thing they ask me about was chicken coups. Hanta virus is a perfect example of a rare one that will only bother susceptible people. Fungi thrives in warm, moist environments. What are lungs? Warm, moist environments. Respirators are definitely a minimum for working with spalted wood. IMO

-- Bob in WW ~ "some old things are lovely, warm still with life ... of the forgotten men who made them." - D.H. Lawrence

View frank's profile


1492 posts in 3630 days

#13 posted 05-18-2010 08:34 AM

Hello tyskkvinna;
....I must admit first that I rarely answer//respond to the many questions that come up on the forums any-more, since so many of those questions have been answered long before. Much like this one here….which if one will notice the search button up there on top in right hand corner and type in ’spalted wood’, one will be taken to here: . Now notice the second one on the list: ’Turners beware of Spalted Wood , which is a golden oldie of what you asking. Believe me I am not trying to ‘dis’ you or ‘put you down’ for your question, but just trying to show you how to research first on this website and then if you still have questions you can reply by comment on the blog or forum….or even email. Actually I suspect this is why a lot of the old timers here don’t write or post on the forums, since we’re all so busy and if it’s been asked and answered before why answer again?

However since the many opportunities and dangers can be so great with ‘spalted wood’, I will again post my answer that was wrote way back then, but still just as pertinent today. Also remember that the dangers of working with spalted wood include eventual death many-many years down the road in some cases. So if we’re talking of allergies, contact or breathing, this is one aspect of the wood that is very beautiful for buyers, but must be protected against becoming dust. I myself use spalted wood much of the time and even make my own for objects of ‘wood art’ that I sell….and again let the woodworker beware and informed. The great joke among woodworkers is that once the wood has dried out and the fungus stopped, it loves moisture and so once it meets your lungs where moisture is again re-introduced….the lungs themselves be-come ’spalted lungs’ ! You also might read that first comment by Don and follow the link he has put there.

Now lets get on with my comment….

Hi Mike;
—-yes the spalted woods can be bad news if your not protecting youself….

There’s a saying that goes like this: ’spalted fungi’s love the wet, when in your lungs they’re feeding to hearts content’….

I try to do all my sanding with the spalted woods in the spring or late summer-early fall ‘outside’ of my shop as I never thought much of wanting all that dust inside. Now being a yankee its hard to teach an old dog new tricks, but when it comes to working with spalted wood and protecting myself I’m all ears and have learned alot, since its those small things that can save your life. I even remember when no one was talking about or telling woodworkers to beware and yes there was a time I took no percaution. I give thanks that God protects the foolish and ignorant such as I was, but now I try to help him out some and take some percautions myself.

Spalted wood for woodworkers on the sellers market is a very hot item to sell and once you have sealed the wood fibers, the wood is quite safe for non-food ‘wood art’. I do not believe that I would ever use a spalted wood for a piece of wood related item where the use was going to be for containg food!

Its in the sanding, cutting and turning process that we as workers of wood need to protect ourselves. Like I said above I do all my cutting and sanding outside, not sure how a wood turner is going to move their lathe in and out so I would think that if your going to turn wood, then Don has shown us a very good answer to the need of protection. I myself am looking into getting one of these ”Triton Powered Respirator’s” and also exploring other avenues.

Getting back to working with the spalted wood outside, well every day I am in this process; I use ‘extreme measures’ to protect myself from breathing and or getting the dust on myself—body. I start by suiting up every day in a pair of clean overalls that zip up completly to my neck and then will wrap a cotten tee shirt again completly around my head area covering my forehead and back of neck. I then tie around my sleeve area and proceed to put on my dust mask respirator, face goggles and ear protectors which also I might add contain my music sound system—-’I mean when your sanding, you gotta rock’. Last of all is the putting on of gloves and I’m ready to go, some who have seen me in this attire have commented that I look like something out of a star wars movie.

I will say that when I am in this part of the wood process, my days are long 10-12 hour days in this body dress and I don’t come out till the end of the day. I then reverse the process for removal of gear and ‘make sure’ that the mask is the last item off, just before stepping into the shower to clean up. As I work in and sell rustic furiture, the spalted woods are too hot of an item for me to give up and so I do my best to protect myself. It is in the area of my beard that I sometimes wonder about, of what if any dust is seeping in under the mask and again this is why I am looking into other areas as how to protect myself.

I’m not saying this technique I use is the answer to others need of protection in working with spalted woods, but I am trying to show how I have seriously tried to protect myself. The best way for a woodworker to protect themselves from spalted wood fungi would be to give up using it! And then also remember,those wood fibers are only safe as long as you have ‘sealed the wood fibers’, and will remain that way only as long as the ‘wood fibers’ remain sealed. Spalted wood fungi once dry and then allowed to come into contact with wetness (eyes, ears, mouth, nose and lungs) will come back to life and start working again, when its in the wood its beautiful—-when its in your lungs its bad!!!


-- --frank, NH,

View Bendilys's profile


1 post in 2395 days

#14 posted 05-18-2010 11:04 AM

Spalted wood isn’t exactly rotten, but it’s on its way. Spalting occurs in an early stage of the decay process, when various colonies of fungi stake their claims to a piece of fallen wood. The characteristic blue-black lines that run through spalted wood actually represent the lines of demarcation between incompatible colonies of micro-organisms. But the specific biological facts aren’t what interest most woodworkers in spalted wood, it’s the fact that nothing else looks quite like it.

-- Benson, Pacific Northwest,

View rance's profile


4243 posts in 2585 days

#15 posted 05-18-2010 12:45 PM


Whether it is Spalted, Cocobolo, or just regular dust, you should do your research and take some precautions. Cocobolo affects some, and not all. It’s not just the spalting you need to be aware of. I’m not suggesting you wear a clean suit, but you don’t need to be breathing ANY more dust than necessary.


-- Backer boards, stop blocks, build oversized, and never buy a hand plane--

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