Black locust bowls

[Robert Marshall]

From a tree cut in July in Atlanta, turned a couple of weeks ago, and then finish-coated with 3 coats of epoxy. I believe these came from opposite sides of the same log cut down the middle, although they look rather different. Both half-rounds were cored into 3 bowls; these are the outer (larger) cores in each case.

The wood cuts very smoothly, and wood-database.com says:

Comments: Black Locust is a very hard and strong wood, competing with Hickory (Carya genus) as the strongest and stiffest domestic timber: but with more stability and rot resistance.

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Robert

[Paul Williams]

I have had no experience with locust, but I really like that grain.

[Dave Mount]

I really like the sapwood pattern in the third picture, must have been near a crotch?

Black locust can take on a range of character. The sphere below is black locust -- it has a lot of dark coloration in it, but I have another that I roughed green and haven't finished that is a fairly even sulfur yellow, much like mulberry. I found it to turn pretty nicely as well.

Best,

Dave

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[John K Jordan]

Those look great, much more prominent color and contrast in the rings than any black locust I've had from around here. Mine was all bland. Turns cleanly though, and nice and heavy for utility things. I made a very heavy pencil once for a friend with motor-control limitations.

A possible interesting thing about both black locust and honey locust: they fluoresces bright green under UV light. This is a block of redheart next to locust.

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Since the endgrain of black locust, mulberry, and osage orange can look similar the fluorescence can help with ID. The wood is often used by farmers for fence posts.

JKJ

[Jeffrey J Smith]

Try fuming the Black Locust with ammonia - The sapwood turns a very deep black while the springwood grain remains unchanged - on the pieces I had a while back the springwood was nearly yellow on a field of deep black.
It's been years since I tried this, there's an old photo somewhere - i'll see if I can find it and post...

[Robert Marshall]

Try fuming the Black Locust with ammonia . . .

Thanks for the suggestion. I think I will follow up on that, and see what happens.

I found this post from a while back, with some spectacular fumed-black-locust photos:

https://sawmillcreek.org/showthread.php?170354-Bowls

Here's an example, from that earlier post, a natural-edge black locust bowl, fumed.


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[John K Jordan]

Thanks for the suggestion. I think I will follow up on that, and see what happens.

I found this post from a while back, with some spectacular fumed-black-locust photos:

https://sawmillcreek.org/showthread.php?170354-Bowls

Here's an example, from that earlier post, a natural-edge black locust bowl, fumed.


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Interesting. So the heartwood turned dark while the sapwood stayed white. I've never tried it. I'll have to try this the next time I turn something from black locust. I see Dave said the finish must be applied quickly after fuming, presumably to preserve the color.

I'm assuming any wood that has high tannin/tannic acid content that can be ebonized by treatment with iron/vinegar (acid) could also be affected by ammonia fuming, woods like oak, walnut, cherry, and mahogany. Is that right?

I read once of a built-in installation, oak, I think, where ammonia fuming saved the day. The article said they sealed and fumed the entire room overnight. If there is a health hazard from a small tent with ammonia it makes me wonder how they cleared the room the next day!

JKJ

[Robert Henrickson]

Interesting. So the heartwood turned dark while the sapwood stayed white. I've never tried it. I'll have to try this the next time I turn something from black locust. I see Dave said the finish must be applied quickly after fuming, presumably to preserve the color.

I'm assuming any wood that has high tannin/tannic acid content that can be ebonized by treatment with iron/vinegar (acid) could also be affected by ammonia fuming, woods like oak, walnut, cherry, and mahogany. Is that right?

I read once of a built-in installation, oak, I think, where ammonia fuming saved the day. The article said they sealed and fumed the entire room overnight. If there is a health hazard from a small tent with ammonia it makes me wonder how they cleared the room the next day!

JKJ

I fume white oak frequently with household ammonia, with good results. Heartwood darkens far better than sapwood. Red oak does not do nearly as well. There is no need to use ammonia which is any stronger than household ammonia. (The common advice in sources to "get the ammonia from your local blueprint business" shows how old the advice is). Household ammonia is unpleasant to smell, but not particularly dangerous. I haven't found it necessary to apply a finish coat immediately -- often it may be weeks. No change of darkening.

I prefer fuming to the vinegar/iron approach, which usually blackens white oak uniformly -- hence "ebonized". I prefer fuming since it allows the grain color variation to remain visible, usually enhanced. I don't work with walnut -- it disagrees with me. I'm not sure what the effect of fuming on cherry would be -- haven't tried.

The story about fuming a room overnight is in George Frank's book "Adventures in Wood Finishing" -- he did it. With very concentrated ammonia and heat to vaporize it overnight -- it even penetrated a preliminary finish coat on the oak! Even with ventilation the next day, I can't imagine anyone would want to be in the room, but apparently the day after the bank opened for business

[Thomas Wilson80]

What is the actual procedure for fuming? Do you just put it in a spray bottle and mist it or is it more complex?

thanks, Tom

[Jeffrey J Smith]

I used a 5 gallon bucket, a small saucer in the bottom with ammonia and a few blocks to raise the bowl up over the bottom. Put a lid on it and let it go. I left the locust in over night as I recall.

[Rob Luter]

Around these parts they call Black Locust "Ironwood", and for a good reason. It's great at dulling chainsaws, plane irons, chisels, etc. It burns hot as blazes too, making your scrap and offcuts good stove and fireplace wood.

[Robert Henrickson]

What is the actual procedure for fuming? Do you just put it in a spray bottle and mist it or is it more complex?

Closed container is necessary. I use plastic tote boxes of various sizes, depending on the size of the thing to be fumed. Ammonia in several recycled plastic containers. For a large tote, perhaps a couple cups of household ammonia. Rate and degree of darkening are variable for white oak, but 48 hours seems to be a good rule of thumb.

[Robert Marshall]

Not having any experience with ammonia fuming, I'm not clear on what concentration is typical for "household ammonia." Many listings show very low concentration (1%, more or less). Can you be any more specific about what you have used successfully, for fuming? Maybe a brand name? Or a source? I would prefer not handling the lab-grade 28% concentration stuff, but how low can you go and still achieve a substantial darkening?

Many thanks for sharing!

Robert

[Rob Luter]

Not having any experience with ammonia fuming, I'm not clear on what concentration is typical for "household ammonia." Many listings show very low concentration (1%, more or less). Can you be any more specific about what you have used successfully, for fuming? Maybe a brand name? Or a source? I would prefer not handling the lab-grade 28% concentration stuff, but how low can you go and still achieve a substantial darkening?

Many thanks for sharing!

Robert

I fume quite a bit, and invested in a gallon of "lab grade" ammonia from the Blueprint store. A couple ounces is all you need. That said, janitorial strength will work just fine. You just use more or it takes a little longer. Household requires more and takes longer yet. Ben Strano at FWW did some tests using all the above and had similar darkening results. Link HERE (https://www.finewoodworking.com/project-guides/finishing/the-best-ammonia-for-fuming-white-oak)

In my experience, warm temperatures help the process. I do small projects in a big plastic tote with a tight fitting lid. I set it on by deck in the sun so it gets nice and warm. I've also use a 36 x 36 x 48 cardboard box with all the seams taped and just drop it over the top of larger projects. I've seen refrigerator sized cartons and tents made from plastic sheeting used for larger end tables and chests. My BIL uses his pickup truck bed with a cap on it. You just need a reasonably sealed environment that can be ventilated. I never do this indoors. I pour the ammonia in a plastic dish and place it under or next to the work. It doesn't really matter as the fumes fill the container.

[Dave Mount]

Definitely a duration times concentration thing. I have a white oak workbench that spent several months in my father's barn after our last move, before I got the shop built. When I moved it out, it had been beautifully fumed by ammonia originating from horse urine -- it wasn't that strong, but with months to work, it still fumed the piece. Only problem was the light patch where the moving company's sticker had been!

Best,

Dave

[John K Jordan]

Around these parts they call Black Locust "Ironwood", and for a good reason. It's great at dulling chainsaws, plane irons, chisels, etc. It burns hot as blazes too, making your scrap and offcuts good stove and fireplace wood.

I plan to take down a black locust tree in my yard sometime this winter. Anyone near me want some for woodturning let me know.

JKJ

[Robert Henrickson]

Not having any experience with ammonia fuming, I'm not clear on what concentration is typical for "household ammonia." Many listings show very low concentration (1%, more or less). Can you be any more specific about what you have used successfully, for fuming? Maybe a brand name? Or a source? I would prefer not handling the lab-grade 28% concentration stuff, but how low can you go and still achieve a substantial darkening?

Most of the time I've used Kroger's own "All Purpose Ammonia". I can't see any data on concentration. I think once on a jug from ome other store I may have seen 5%. I've gotten very strong darkening. I've occasionally used household ammonia from other chain stores. Mostly the darkening depends on the individual tree, and often a specific part of a plank. Stress wood will darken more than regular heartwood. I just leave it in the tote until the darkening is what I want, or doesn't seem to be getting any darker. Two days is generally enough, and putting finish over it darkens it further. It will NOT yield the same degree of darkening every time. Sapwood (white oak) will not darken much. I use household ammonia since, like you, there is NO way I would use any of the more concentrated versions. As I said above, I use it a lot with white oak, but very rarely with any other wood.

[Robert Marshall]

Thanks to all who contributed to the discussion, particularly the "fuming" idea, which was new to me.

What a great place, Sawmill Creek woodturning! You come for the Ooohs and Aaahs, and stay for the new ideas, complete with all the "how-to's" and the "do's-and-don't's", all the stuff you need to know.

Robert