Roasting wood?

[Michael Anderson]

Hi all. I’ve been messing around the variety of colors that show in wood upon upon moderate burning with a blow torch. The problem, of course, being it is easy to go too far—most of the “richest” colors show up just prior to charring. For example, cherry heartwood turns a deep burgundy color when heated just the right amount. I would like a more foolproof way to “capture”.

I know that there are nice examples of this (ex torrified maple, and various sand-shading for marquetry and intarsia), but I haven’t found much in the way of variety. Do any of you have experience with roasting woods? If so, do you find there is a certain temperature that is ideal? (relative to flashpoint — 90% temp of flashpoint [obviously the exact temperature will vary somewhat]).

 

[Gary Beasley]

For small parts cooking in the oven does the job. Have to experiment with temp and time to get the exact result.

 

[Michael Anderson]

Thanks Gary. I have a bit of an experiment set up in my head for this. I’m going to refine it a bit and then post results at some point.

 

[Monty Ivy]

Woodworker's Source stocks some roasted wood. https://www.woodworkerssource.com/lumber/roasted-dark-lumber.html. Might be an easy way to try some out to see how it works for you.

 

[Michael Anderson]

Thanks for the website Monty--it's nice seeing those colors! Who wants to take the easy way though? Then, I won't be able to report back about the idiot that burned his house down try to roast wood in the oven. Kidding, kidding, kidding...

 

[Monty Ivy]

Thanks for the website Monty--it's nice seeing those colors! Who wants to take the easy way though? Then, I won't be able to report back about the idiot that burned his house down try to roast wood in the oven. Kidding, kidding, kidding...

And in local news, a Chattanooga man had to be resuscitated after accidental smoke inhalation and was treated for minor contusions at the scene. Spouse was arrested for assault but was released after the district attorney declined to prosecute.

 

[Michael Anderson]

And in local news, a Chattanooga man had to be resuscitated after accidental smoke inhalation and was treated for minor contusions at the scene. Spouse was arrested for assault but was released after the district attorney declined to prosecute.

Hahahahahaha, that has me laughing out loud.

 

[Lynn Dudenbostel]

Torrified wood is cooked in a vacuum, i.e. absence of oxygen. I will say after building 2 guitars and a mandolin with torrified spruce, and my son building a guitar neck with torrified maple, I have no desire to ever use it again. The odor from this stuff is awful! And it lingers around in you shop vac or dust collector for a week or more, reminding you of how nasty it smells!

 

[Michael Anderson]

Torrified wood is cooked in a vacuum, i.e. absence of oxygen. I will say after building 2 guitars and a mandolin with torrified spruce, and my son building a guitar neck with torrified maple, I have no desire to ever use it again. The odor from this stuff is awful! And it lingers around in you shop vac or dust collector for a week or more, reminding you of how nasty it smells!

Thanks for the input Lynn. Unfortunately, no vacuum kiln here, though I did read that covering the wood with a few layers of aluminum foil can help achieve better results than uncovered.

Really interesting re. the smell! I would have never thought. Also, would love to see a photo of that mandolin if you have one laying around.

 

[Lynn Dudenbostel]

Because the top is stained to a traditional sunburst finish, you can't really see the effect of the torrification. It just looks like a regular sunburst, only a bit muddier. The use of torrification in instrument wood is an attempt to artificially age it to try and bypass the break in period off a new instrument. Some folks swear by it, others think it's snake oil. I don't think I saw much of any improvement. Stick with stains to get the color you want. At least spruce and maple just get muddy looking when it's roasted. Kind of a grey color.

 

[robo hippy]

I think some woods might smell good, while others would not. Persimmon for sure smells terrible if you try to microwave it.

robo hippy

 

[Michael Anderson]

I think some woods might smell good, while others would not. Persimmon for sure smells terrible if you try to microwave it.

robo hippy

Someone recently posted something somewhere about microwaving Elm—his wife banned him afterward because the kitchen smelled like urine for a week. Haha

 

[Michael Anderson]

@Lynn Dudenbostel right, that makes sense for those woods. The “age-ification” process is interesting in itself. I follow a couple of violin makers on Instagram and it’s always a fun to witness the conversations that come after they start scratching, scuffing, and everything else their freshly finished interest. People get heated, probably more than necessary.

 

[Lynn Dudenbostel]

Well, the violin world is kind of like that. They are also the ones (along with some guitar people) that put a lot of stock in the properties of spruce harvested during a full moon. Google "moon wood". It's crazy. I can imagine there might be (emphasis on might be) some fluid pressure changes in the sap wood, but often the sap wood is not used in the top. Possibly a little sap wood in larger instrument tops. A friend who is a retired forester, tone wood dealer and violin builder doesn't believe in "moon wood".

 

[Michael Anderson]

Moon wood, that is very interesting--might be one of the more far fetched things I've heard!

 

[Karl Loeblein]

Here’s my first attempt at making torrified Silver Maple. Baked a white board in toaster oven at 220, 280, 350 and 380 degrees for 30 minutes at each temp. Mostly wanting to see if roasting the maple would help show off the chatoyance more than the leaving it plain. Also, torrification is better than staining since the brown color is throughout the entire board. I can see why guitar makers like this process.

Top board is sealed with ultra thin CA glue then buffed in out. Bottom left plain for comparison.

 

[Michael Anderson]

That is very cool Karl--I think your objective was achieved. The chatoyance comes through very clearly in the torrified board. Thanks for the photo.

Unrelated note--Millington! My wife is from Munford, and has a lot of family in that area--folks in the big three, Munford, Millington, and Bartlett. Small world.

 

[Lynn Dudenbostel]

Torrification is carried out at 200 degrees centigrade and higher in an inert atmosphere. Going to be difficult to provide an inert atmosphere in a toaster oven. Often the temperature is great enough that without the inert atmosphere the wood would combust.

 

[Michael Anderson]

Even if it’s not torrification by a strict definition, I’d be happy to reproduce results like Karl. I think there are ways to limit the wood’s access to oxygen (thus preventing combustion and mitigating charring). Not as ideal as a vacuum chamber of course, but pretty close. That said, the structural changes may differ with roasting in an oven vs a controlled chamber, but if the color change is similar I’m satisfied.

 

[John DeSalvo]

Do you think a heat gun would have any effect? I use one to bring out the purple in purpleheart, it really turns it purple in a short time. Obviously you would have a hard time doing a plank with any consistency, but a turning might work pretty well.

 

[Michael Anderson]

Thanks for the response John. I had not thought about the heat gun tactic—it could work for some cases, but might be a little bit more inconsistent than sticking the whole piece in an over. I actually don’t even own a heat gun, but maybe this is the excuse I need to justify buying one haha.

 

[wnnelson]

The aluminum foil idea may work but metal heat treaters use stainless steel foil to keep the metals from oxidizing. This material holds up well even at very high temps. Not sure of the expense for the size of your projects. Fold up a envelope of appropriate size and seal the opening by folding over a seam. You could add some inert gas into the foil envelope to displace the oxygen. MAKE SURE IT'S INERT. This would be easier than a vacuum system.
I like your idea and look forward to your results.

Bill Nelson

 

[robo hippy]

I wouldn't think that guys need to be reminded about cooking wood in the home microwave, but, well, some just don't think. That is as big of an offence as using her fabric scissors to cut paper.... I had a friend who had a microwave in the shop and he put some persimmon in it, and forgot after turning the knob rather than a timer.... he is very 'frugal'. Anyway the smell kept him out of the shop for a day or so....

robo hippy

 

[Lynn Dudenbostel]

Also, remember that "cooking" wood by any means will dry it out considerably. Make sure you let it sit for a while and acclimate to your shop environment. Weight it occasionally.... Wait until it stops gaining weight from moisture in the air. (That sure sounds weird to turners, huh!?). That will help prevent unwanted movent in your final piece.

 

[Michael Anderson]

@wnnelson Bill, thats a fair point about stainless steel foil. I will look into it. And right—flooding the envelope with an inert gas is something I thought about. Nitrogen would be easy enough, as you can buy canisters for cheap.

@robo hippy yeah, hahaha. I’ve tried to avoid the stink woods in the microwave. Closest I’ve come to domestic abuse (kidding, kidding) is when I microwaved some sweetgum. Give the kitchen a slight leather/tobacco smell for a few hours. All told, not that bad!

@Lynn Dudenbostel absolutely. This is something I would use for greenwood turnings and embrace the wonky form, or would wait until something is stabilized to ambient. The idea that the color change throughout the thickness of the blank is pretty exciting (as opposed to just a surface-level change).

 

[Karl Loeblein]

Buy a used toaster oven at a thrift store or Facebook Marketplace, and do this cooking outside and keep the wife happy. As for me, I bought my wife a newer oven so I can have the old one for my shop. win win…

Look thru this thread for a little more info:

https://www.aawforum.org/community/...ut-losing-authentic-color-appeal.18337/page-2

 

[Michael Anderson]

Good call Karl, I probably will do that. And thank you for the link—a lot of good information there!

 

[Barry Richardson]

Now ya got me thinking.... has anyone cooked a roughed out hollow form? guess ya might need a full sized oven.... Might jazz-up a boring piece....

 

[Michael Anderson]

Now ya got me thinking.... has anyone cooked a roughed out hollow form? guess ya might need a full sized oven.... Might jazz-up a make a boring piece....

I’m not sure, but I assume it’s been done. My primary interest is for a green turning that has already warped and settled. But given the full thickness color change, it would be very cool for HF and rough tuned bowls. Something enticing about sticking a big form in the oven

 

[Karl Loeblein]

I suspect a torrified hollow form is too risky considering the amount of work for hollowing. Definitely make sure wood is dehydrated at lower temps and watch carefully for any signs stress cracks before slowly turning up the heat. Don’t even think about trying this method if you noticed any cracks develop during the hollowing unless it’s something that didn’t take long to hollow like a Christmas ornament. If you want to make something bigger then consider making a segmented hollow form using torrified boards.

 

[robo hippy]

Hmm, I did microwave a couple of pieces when I first started, but found it easier to just let them air dry. Part of that may have been because I was doing production work. A friend had a dehumidifier and a light bulb in a sealed shed, and it took him a month or more to dry his wood. Only way I would think of accelerating the drying process would be steaming. To me, if you use dry heat, the risk of cracking goes way up, and even though wood does grow on trees, I still don't like wasting it. Maybe I am just stuck in my ways. I prefer natural colors of wood, and very warped....

robo hippy

 

[Michael Anderson]

@robo hippy some good thoughts there, that I might add to the experiment that will come in the future. Maybe a pan of water in the oven during roasting could help alleviate cracks.

Nothing beats the natural color of wood, for sure, but sometimes it’s fun to bring out crazy tones without paint/stain/etc… definitely also agree with warped. Such cool shapes

 

[Leo Van Der Loo]

Michael I have some info here or you on how to go about it, adding to this that some said to get some moisture into the wood as it can become quite brittle. also it needs a finish or the wood will turn a grey color over time.



Here is a roasted/toasted/carmelized Maple bowl with Mahogany stripes.

 

[Michael Anderson]

@Leo Van Der Loo

Thanks for the information, Leo. It’s helpful. Also interesting to read about the comparison with PTL.

That bowl is beautiful as well! It’s a nice combination of the forum buzz lately, haha—wedges, stripes, and roasted wood.

 

[Michael Anderson]

I had some spare time over the weekend, and ran a little intro roasting experiment on some scrap pieces of Cherry and quartersawn White Oak.

My roasting protocol was fairly basic - 20 minutes at 200F, 20 minutes at 300F, and 60 minutes at 400F.

In the images, the first (left) column is normal, unroasted. The second (middle) column is roasted uncovered. The third (right) column is roasted and wrapped in tinfoil. The top half of the images is cherry, and the bottom half is white oak. The first image is unfinished wood, and in the second image the wood was wiped with Howard's Feed-N-Wax, which is just a blend of orange oil, beeswax, and carnauba wax. I did not spend much time at all sanding, which especially shows with the cherry.




To me, the star of the show is the middle piece of white oak (roasted uncovered). The photo doesn't do it justice, of course. The cherry may have benefited from a finer surface, but I think the third piece (roasted and wrapped in tinfoil) trends toward the color I was hoping for. That said, I need a bit more work, as it sort of looks like aged cherry, rather than something else. Stay tuned for more at some point! This is just the start.

 

[Richard Coker]

Do you think a heat gun would have any effect? I use one to bring out the purple in purpleheart, it really turns it purple in a short time. Obviously you would have a hard time doing a plank with any consistency, but a turning might work pretty well.

 

[Michael Anderson]

@Richard Coker a heat gun would be pretty cool to try. The only problem would be with consistency, which is the same issue with a torch. The benefit of roasting is uniformity on the surface and the interior of the wood. However, a heat gun could be the way to go if you want to isolate regions of the turning.

 

[Mike Zip Hamilton]

Two things:

If you like the white oak, you might try fuming with amonia.

I'm thinking of trying larger items in my gas grill.

 

[Michael Anderson]

Thanks Mike. I've never tried fuming with white oak before (I have with brass though, to accelerate the patina process). Would be a fun technique to try! John Jordan's fumed oak pot he made relatively recently is stunning.

 

[wnnelson]

Interesting results. It appears that oxygen or some other gas present in air makes a significant impact on the color. Did you put a inert gas inside your foil envelopes? Possibly investigate different gases for different effects? Did you cut the pieces to see if the process actually goes all the way through the wood? Good work here keep it up.