Inducing Spalting

[kaysa]

This is my second attempt at posting this. So if the original turns up, I apologize in advance for spamming the system.

The article I wrote for Fine Woodworking on DIY Spalting should be coming out this Spring. You'll find it much more in-depth and informative.

Now to the question: How to induce spalting.

Spalting is caused by fungi. There are many different types of fungi, and all have their own special sort of decay, color patterns, etc. The main thing about inducing spalting is to consider what fungi need to grow: darkness, moisture, nutrients, time. So lets consider these in detail.

1) Fungi like to incubate in the dark. Your basement works well for this. Try to keep the pieces of wood you are spalting covered. This serves not only to keep them in the dark, but also keeps in moisture. See point 2.

2) Fungi need a high humidity to grow. Getting fungi to grow on wood means you need to keep the moisture content of the wood high (above 20%) AND you need to keep the relative humidity of the bin you put your wood in high (80-95%). Remember that fungi do need oxygen, so submerging your wood in water doesn't help.

3) Fungi need to eat. And they do eat the various components of wood, the cellulose, hemicellulose, and lignin. You don't need to suppliment their diet at all to get them to grow. However, they will grow faster (thus decaying your wood more quickly) if you give them additional nutrients.

Many websites recommend beer. I'm pretty sure this is more for the woodworker than the wood. The part of the beer thats helping is the malt, which is also an ingredient Mycologists use to grow fungi in those little petri dishes in the lab. But it would probably be cheaper just to go buy the malt in bulk. Or use malted milkshakes. I prefer those to beer anyway.

4) It takes time for the fungi to colonize the wood. Leave them too long, and your piece gets soft/crumbly. Too short a time means the colors don't go all the way through. There is research published on some common spalting fungi with EXACTLY the amount of time it takes for them to produce zone lines without losing the integrity of the wood. You can find these papers here (both are actually mine):

http://goliath.ecnext.com/coms2/gi_0...-maple-by.html

and

http://goliath.ecnext.com/coms2/gi_0...bility-in.html

These links give you the text without pictures. You can find other articles that talk about which fungi produce zone lines with other fungi, but they lack the timetable.

I hope this helped everyone!
Seri

[woodArtz]

Awesome information. I will definitely give it another try. Since I missed with the poplar, do you have some suggestions on other woods that work well. Obviously, maple seems to work ok. Thanks for the great information!!!

[kaysa]

Originally Posted by woodArtz

Awesome information. I will definitely give it another try. Since I missed with the poplar, do you have some suggestions on other woods that work well. Obviously, maple seems to work ok. Thanks for the great information!!!

The Ohio DNR did some research into this and found that pale woods work better, obviously because the colors have a better contrast. You should also try for woods with low extractive contents...so woods like black walnut and teak are out of the question.

Maple, birch and beech have been hailed as the three best spalting woods. I find sugar and red maple to be my favorites, followed closely by silver maple. You get a fantastic sort of 'moonscape' pattern when you spalt silver maple.

[woodArtz]

Here's some maple I got locally. I just love the stuff.

[kaysa]

It's beautiful! It has zone lines and several stages of bleaching. What a fantastic find!

[DaveO]

Seri, thanks for the very informative thread. There is a turn wood supplier near me NCWood http://stores.ebay.com/NCWood that does his own spalting and really produces some beautiful stock.
Here is some Hackberry that he spalted -



I think that he has the timing down just right. Very heavy zone lines and color, but still a pretty solid piece of wood. I had to use a little thin CA to stiffen a few punky areas.
Dave

[ChrisMathes]

Seri,
Thank you for taking the time to post. This is good information and I will be experimenting (insert evil mad scientist laugh)! A few quick questions:
1) Do I need to prime the wood with fungi or will that come naturally?
2) Can I control the 'design' at all? I'm guessing that is a property of the wood and the fungus and how the different colonies grow. However, can I at least control the colors?
3) Are the zone lines always 'black'?
4) Will the spalting/fungus growth cease when you finish the project since you are taking it out of the ideal conditions?
5) Do you have any thoughts/comments about highly figured wood as opposed to straight grained...any difference in timeframe, etc. The attached picture is some sycamore that was given to me by Jeff... on this board. It is some of the prettiest wood I've come across. Unfortunately, this picture does not do it justice, but it is full of curly chatoyance. You can see how the spalting zone lines 'stair step' or are jagged over the curly figure. I want to do that on some boards for some flatwork..that would be too cool!



I admit that I have not had time to read your links, yet, so if these questions are answered there, ignore me, please!

Regards,
Chris

[Bas]

Great writeup Seri. Very informative, and brought with a good dose of humor.

[jeff...]

Sycamore and elm are also great spalters

American elm





Beech is also another good spalter but smells a lot like beer when your cutting it green.

Here's a Sycamore pen Clay made - I took it out of it's special hiding place just for a picture.

[kaysa]

Originally Posted by ChrisMathes

Seri,
2) Can I control the 'design' at all? I'm guessing that is a property of the wood and the fungus and how the different colonies grow. However, can I at least control the colors?
3) Are the zone lines always 'black'?
4) Will the spalting/fungus growth cease when you finish the project since you are taking it out of the ideal conditions?
5) Do you have any thoughts/comments about highly figured wood as opposed to straight grained...any difference in timeframe, etc. The attached picture is some sycamore that was given to me by Jeff... on this board. It is some of the prettiest wood I've come across. Unfortunately, this picture does not do it justice, but it is full of curly chatoyance. You can see how the spalting zone lines 'stair step' or are jagged over the curly figure. I want to do that on some boards for some flatwork..that would be too cool!

You can control the design in a number of ways. Keep a section of wood moister, use chemical preservatives, etc. There are some patents that reference this online which have expired and are now free for the viewing. You can search for them on google, and can view them at freepatentsonline.com

You can certainly control the colors! If you have clear wood and want to start off with a blank slate, you'll need to sterilize the wood somehow. I recommend steaming it if you have that option, for 30 minutes at least. Make sure the water underneath is at a rolling boil. If you skip this step you will have far less control over the color, because fungal spores already have colonized your wood.

Next you'll need to do some research into the fungi that produce the colors you like. I can tell you that the prettiest colors are the fungi that are usually the hardest to get growing and colonizing. Zone lines and bleaching are the easiest to accomplish. For papers that deal with which fungi produce which colors and zone lines, check out the work by A.D. Rayner, the two papers I listed previously, or even just a very good fungus book. I highly recommend the 'Fungi of Switzerland' series.

Zone lines range in color from red to brown to black. Be careful not to confuse them with the black spotting commonly found on pieces. These are not 'young' zone lines, but an entirely different beast.

Once the wood drops below about 10% MC, your fungus will stop growing. It is NOT dead. Get that thing wet again and the fungus will hop right to it. This gives you 2 options: steam sterilize again, or dry it out and shellac shellac shellac.

I'll have to start another thread for your final question about grain deviations. I'll probably get that up later today.

Seri

[McRabbet]

Seri,

If you are willing, please consider writing up good summaries of you posts to go into our Download Library (I can assist by translating them to PDF files). Thanks.

[kaysa]

Would it be better to just put the relevant articles in there instead?

[Trent Mason]

Seri,

I thought I posted a response to this yesterday, but maybe I got preoccupied and closed the window before posting it. Anyway, this is very interesting. I did have a couple of questions for you.

1. Do you have to use green wood for this or can you go to the wood store, pick out a board and go for it?

2. Secondly, I think you mentioned above that the fungi are already in the wood. Yet, you also mentioned getting fungi. Does that mean buying it?

3. Say I wanted to try this. From what I understand, you need to steam the wood for at least 30 minutes. Then do you wrap it up in a plastic bag and keep it damp and in the dark for a month or two?

I hope these aren't stupid questions. I had never even heard of this until you posted about it a few days ago and I'm about as far from an expert as you can get. Thanks very much for sharing your research with us.


PS: I won't use beer if you don't reccomend it, well not for inducing spalting at least.
Trent

[kaysa]

You can use green wood or kiln dried lumber. But if you use kiln dried you'll need to find a way to hydrate the wood. Air dried lumber, if you don't live in a tropical climate, doesn't have a high enough moisture content to grow fungi.

Yes, the spores are already in the wood. But if you want to control the colors you'll need to know EXACTLY which spores are on there. The easiest way to do this is to kill the existing spores and put on your own.

You certainly don't have to buy them. Go take a walk this summer and check out tree stumps and logs. See a nice spalting design you like? Take the associated fruiting body (usually a shelf mushroom) and get to it!

I don't recommend plastic, as that can restrict air a little too much. I would get a bin of some kind, fill it with something that retains moisture (like soil, vermiculite, which you have also steam sterilized), and bury your wood.

For reference, if you're going to take to pouring beer on wood, feel free to use cheap stuff. Its the malt amount you want to watch, not the price tag.

Seri

[ChrisMathes]

I'm going to give a try at answering some of these questions to see if I have 1/2 of a clue. Obviously, Seri, correct me, please

1. Do you have to use green wood for this or can you go to the wood store, pick out a board and go for it?
If I understand correctly, you can use any piece of wood that you want, as long as it has not been treated. That said, a piece of wood from the store should be dry (regardless of kiln dried or air dried). You will need to increase the moisture content of the wood to get fungus to grow in it.

2. Secondly, I think you mentioned above that the fungi are already in the wood. Yet, you also mentioned getting fungi. Does that mean buying it?
I believe she was indicating that fungus is in the wood, but, if you want to create a specific look, you may want to introduce a particular fungus to that wood. For sure, you could do so by introducing a piece of wood with that specific fungus to the target piece (flowers, chocolates and alcohol (beer, especially apparently helps getting the introductions going). I, also, am interested, however, in learning if you can purchase a specific fungus you are looking for.

3. Say I wanted to try this. From what I understand, you need to steam the wood for at least 30 minutes. Then do you wrap it up in a plastic bag and keep it damp and in the dark for a month or two?
I don't think that you have to steam the wood, unless you are looking to kill off the fungus that has currently colonized in there. I think you just need to keep the wood moist/dark, etc, but do not need to steam it to create spalting.

PS: I won't use beer if you don't reccomend it, well not for inducing spalting at least.
Hmmm...maybe we should get a keg and have a North Carolina Woodworker spalting party!!!

Cheers!
Chris