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Turning Bowls from Green Wood - Tricks and Techniques

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Blog entry by RobertJ posted 792 days ago 2719 reads 9 times favorited 6 comments Add to Favorites Watch

Introduction
I’ve been turning large chunks of un-seasoned firewood since I started turning bowls over a year and a half ago. Much of the wood is turned without regard to it’s moisture content…I don’t have time to wait thru the recommended aging periods and I don’t choose to rough turn bowls and set them aside for a few months before turning them a second time. This isn’t about attitude, it’s about loving the experience of turning and accepting the challenge of whatever is thrown my way; including wood that is sometimes so wet that turning results in water and pulp cascading down my face shield. My objective is to learn how to hone my skills while creating custom bowls under a wide variety of conditions.!

Would I prefer turning seasoned wood? Yes, there are moments when I’m saddened to watch a perfectly cut shape turn into something other than what I had envisioned. But I turn 12 to 15 inch bowls and I need sections of wood that come from very large tree trunks. Sometimes I’m lucky and the wood is dry. Sometimes a section is so wet that it weighs 150 plus lbs; but it’s a wood that I’d love to turn like walnut or hickory. I typically fill up the back seat of my Explorer for $20.00 and turn whatever I can get from firewood yards, wet or dry. Finding and purchasing cured blanks of this size is not an option. It’s both difficult to find and expensive. If you’d like to see the various bowls I’ve turned without any regard to moisture content you can visit logfrogswoodenbowls on the internet.

Overview of My ExperienceTurning Green Wood
There are some interesting things to be said about the unconventional approach of turning and finishing green or uncured wood. I’d like to share this information with you. The results seem to depend on the type of wood and the density of the wood being turned, as well as the shape and thickness of the bowl being turned. The surprising thing is that many of the bowls turned from green wood exhibited little, if any, visible warping and were also able to be sanded and finished within three days to one week. Here’s a black walnut bowl from the core of a damp stump. The only negative thing that happened was that the copper band popped out of the groove as the bowl slightly warped. I sold the bowl within weeks after reworking the groove to clean it up and getting rid of the copper wire band.

Some woods, like certain oak species and Dutch elm that I’ve turned green, continue to warp and crack for extended periods of time and require attention and re-work for weeks, even months. Any end cuts with the pith remaining in the bowl can be an extra challenge. The oak bowls below took repeated attention to cracking as the bowl stretched. I seal the cracks with CA glue and fine sawdust followed by additional sanding. The Dutch elm bowl shown below required weekly attention over a period of a couple months. As the artist, you must decide if the more difficult woods and shapes are worth the time and effort, Two of the bowls shown below have gone to proud owners. The heavily warped oak bowl in the middle always gets a lot of attention at an art show but has not sold. On a positive note, some of the warped and cracked pieces have turned out to be my best sellers.

Using green wood from the same source or family of wood, some particular shapes required very little extended attention. Here’s a few examples (below) of bowls turned from unseasoned wet oak:


Specifics on Turning and Finishing Different Varieties of Green Wood

   

Walnut
I am currently turning walnut from a tree that is so green that the stems remaining on the log are green in color and flex rather than snap off. When I turn the wood water oozes out of every cut. But I’ve repeatedly mounted, turned and finished several bowls form this wood with very minor or no cracking and hardly any warping that I would consider problematic. I am also using this wood to detail with a Dremel tool. Within 3 days to one week of turning, after anding and buffing out the bare wood surface, I am able to apply 3 coats of lacquer. The first coat is sacrificial; I use it to raise the grain so I can sand out scratches and scrapes. The following coats are wet sanded with 600 grit. Lastly, I apply a Formby’s Tung Oil hand rub finish over the sanded lacquer coat. Instead of letting the tung oil finish dry, I rag the finish down then buff the uncured finish using the Beale buffing wheels (White Diamond and Carnauba Wax) on the same day that I applied the lacquer. The only precaution I take is to not press the buffing wheels too hard against the finish. The results are amazing and I’ve only spent 3 to 5 days on any 1 project. I can easily have 3 projects going on during the same week. Here’s some recent samples of walnut bowls cut very green and finished (as shown) within 3 to 6 days.

Maple, Dutch Elm, Cherry
I also do not adhere to any special drying techniques. I place the bowls in a room in my house that is out of direct sunlight and away from extreme changes in temperature. All the bowls shown below were cut wet and include maple, Dutch elm, and cherry wood. I keep my eye on the bowls daily and any bowls that exhibit obvious warping are left to dry longer, while those that seem to hold there shape get finished as soon as possible. I’ve watched some of these finished bowls for a year, just to see what happens over time. The maple held it’s shape perfectly. The cherry warped from round to oblong. The Dutch Elm, as mentioned earlier, was trouble from day one but once I felt the bowls had stabilized they sold instantly. I am not always pleased with the shape a bowl takes on as it dries but there are so many pleasing results that I will not abandon the technique.

Avocado
Turning green avocado wood resulted in some bulbous projections that followed the grain pattern and are pleasing to the eye. I was not real happy with the shape I turned but I can put the knowledge of the grain-popping thing to good use in the future.

Ash
I’ve turned several large ash bowls without ANY problems. The wood was not “green” but I paid no attention to moisture content when I turned them. Here’s an example:

Camphor
I’ve turned several green camphor bowls without any warping or cracking beyond what I encountered on the day they were turned. The gentleman that purchased this bowl put it on display as a piece of art (much to my surprise and pleasure). This wood was very wet. The thin wall and large open shape allowed the bowl to stabilize extremely fast. It took a finish within 3 days.

Here’s some more camphor that was turned wet and finished within a week:

Apricot
Sometimes amazing things happen, as did with this large bowl cut from the core of a root stump from an apricot tree. No warping, rapid finishing and just an amazing crazy piece to look at.

Hickory
This wood, which I think is hickory, was so wet that is was pulpy along the band beneath the bark and overall very difficult to cut with my 3/4” bowl tool. I don’t particularly care for the thick wall cut I did but I was amazed how fast it stabilized, allowing me to finish it in the same week it was turned. I have another large chunk of this wood and will try a more delicate shape.

Tricks when Dealing with Green Wood Turning and Finishing
Part of the problem in the first few months was that, as a beginner (which I still consider myself), I did not understand “form”, I was in the experimental stage with finishing (which continues to this day) and I didn’t have a clear understanding of how a particular shape will warp or crack. Again, it also depends on the type of wood, some woods warp so slightly that it isn’t noticeable to the untrained eye.

When a bowl warps it may go from perfectly round to oblong with the end result being less than desirable. If there is any knot or change in grain, warping will often concentrate in this area; the bowls always seem to elongate towards the denser darker grain areas of the wall or sides of the bowl. As a bowl dries, the bottom, once perfectly flat, may curve. In a worse case scenario a crack may result from the stresses at the bottom, side or rim. I now leave a deep foot which counter acts the warping and allows extra wood to put to the belt sander if needed. The one thing I can nearly always count on is that the top or rim of the bowl will rise and fall at changes in the grain. Also, over the first 2 days of drying, the grains tend to raise and a light sanding is needed to get the surface smooth to the touch again. This is actually a beneficial finishing process because you’ll notice things that you missed the first time around.

To offset some of these conditions I have learned to take certain steps. It should be said that I now mount my blanks (cut with a chain saw) from one side only, using a 4 screw faceplate on the bottom. The first couple of inches of the bottom are sacrificial and will become waste so that no screw holes are visible. I shape the outside of the bowl from the rim to the bottom, use a large scraper to smooth out the shape and surface, then power sand the outside with a right angle drill and 2” flex sanding discs with the bowl spinning at various speeds. I often use a long piece of silver oxide sanding tape (used for sanding copper pipe joints) to sand the exposed side at the foot of the bowl and the transition between the foot and the side of the bowl. Sometimes I’ll continue with the sanding tape over the entire outside of the bowl. I’m using a 120 grit tape. Occasionally I will run an orbital sander over the surface with the bowl spinning at a slow speed. If a decision is made to tool a bead or beads round the outside, I do it right away, before the bowl starts warping. I also make my initial parting cut at the bottom of the bowl. The objective is to get as much of the shaping, tooling and sanding done as possible because the green wood will start changing shape and even minor warping will cause your tool and sander to jump and skip. Hand sanding becomes your alternative.

The next step is to start hollowing out the center of the bowl, followed by the use of a scraper and sanding to smooth out the interior surface. It is at this point that I make a decision whether to dismount the bowl, leaving it on the faceplate or removing it if I’m starting another project, and storing it in a shady room in my house. I often choose to apply a finish (Formby’s Tung Oil Finish or spray lacquer) and go through a second sanding cycle with the grains raised before dismounting. I also take this time to CA glue any cracks with CA “thin” followed by a dusting of fine sawdust rubbed into the crack with a dusty rag and a second bleed coat of CA glue with a second dusty rag rub. It’s better to apply the glue with a sacrificial finish in place so the glue will not permanently darken the wood adjacent to the crack. I will sand this repair within minutes using flex discs, then re-sand the entire surface to even out the repair area. I can now look at the wood and feel the wood and generally know if I’m dealing with a piece that will experience light or heavy warping. You can also feel if it is too cold and wet to continue finishing prep. If it appears stable, I will buff the outside and inside with tripoli compound to remove light scratches and white diamond compound to semi-polish the surface. If I am using the tung oil finish (not pure tung oil) I may apply a second coat (after the initial sacrificial sanding coat) and buff it out immediately using the white diamond wheel and rags. Lastly, I make a parting tool cut at the bottom where the final cut will be made. I will then set the bowl aside and watch and feel the wood over a period of 2 or more days. The benefit of starting the parting cut at the bottom is it will allow a portion of the foot to dry faster. Typically the grains will raise and the rim will become wavy as mentioned earlier.

If the bowl appears to be stable, I quickly remount it on the lathe, re-turn the rim to remove the wavy surface and do a medium to light grit sanding over the inside and outside of the bowl. I part the bowl from the faceplate using a sharp parting tool followed by the use of a hand saw. I use a belt sander to flatten out the bottom followed by a light hit with the orbital sander and finally hand sanding. If the bottom center is damp I let it dry but I am usually able to apply two coats of lacquer within a couple hours, wet sanding with 600 grit between coats. I may delay doing this at the bottom if it is too damp, applying a finish later in the week. Later in the day I apply a thin coat of Formby’s Tung Oil Finish over the lacquer after the wet sand and/or use of fine steel wool (light pressure) on the lacquer. I rub the tung oil finish coat with a rag to remove excess and then polish the uncured finish with the white diamond buffing wheel (no or very little compound used). I follow this step with a light buffing using the carnauba wax wheel. Warning: If you apply several coats of lacquer and buff it out the same day or fail to sand between coats you may burn through the finish if you apply too much pressure with the buffing wheel. If you have thick layers of lacquer you must allow the lacquer to dry over a 1 week period. The 1 day finish I am describing utilizes thin sanded coats that gives the bowl surface a pleasant grain enhancing sheen. The reason I apply the Formby’s over the lacquer is to even out any uneven sheen in the thin lacquer coats. The surface can be maintained with wax or hand rubbed oils.

I realize that many artists and turners like to use a multi-layered cured finish. I prefer the natural look of the wood grain and started out just using walnut oil and moved on to pure tung oil. The problem is that with green wood the finish would be uneven and would create dark spots when I buffed it out because the surface was gummy from the combination of oils and water in the wood. The use of thin lacquer layers and/or Formby’s Tung Oil Finish allows immediate buffing and provides an even sheen. The wax application brings the finish to life but the seal it creates is not 100%, allowing the walls of the bowl to continue drying over time. I may steel wool the finish and do another Formby’s finish and wax-buffing if needed.

I have buffed out bowls with fully cured lacquer coats. You can still scratch the finish and the repair requires re-sanding and additional lacquer coats. My finish is thinner and can be repaired with a rag and the wipe of a little Formby’s Tung Oil. Is it waterproof? I always ask people that purchase my bowls to treat them like natural wood. Do not soak. Do not leave in direct sunlight for prolonged periods of time. Rinse lightly, wipe clean and dry immediately. Apply oil or wax as needed. It’s not bullet proof but it looks just fine. I’ll typically hand buff the bowl using Renaissance wax, a very hard wax) before displaying or selling the bowl.

More Interesting Tips
Knowing that certain woods warp differently but that the rim nearly always goes wavy within 3 days, I noticed that natural edge bowls rarely needed any follow up since the edge is irregular anyway. Natural edge bowls tend to warp so that the shape collapses into itself. To counteract this I’ve started doing a more dramatic V cut. With a deep foot blended into the V cut I cannot notice any irregularities in the green cut wood.

Potential Long Term Problems
 I can hear someone asking “what will happen to your bowl over time if it has not fully cured prior to finishing”? As I said earlier, I’ve held onto some bowls for over a year to observe what happens. Only woods that were prone to cracking (some oak and the Dutch Elm in particular) continued to develop cracks. But if these same woods did not show any initial cracking, it seemed that there were no surprises over the long run. Basically you learn to make these observations by trial and error. Again, I’ve been able to offset some of this by using specific shapes and increasing the foot depth at the bottom.

Here are a few most recent green wood turnings using my quick finish technique (these bowls were cut and finished in 1 to two days):

-- RobertJ, Southern California



6 comments so far

View SASmith               's profile

SASmith

1566 posts in 1612 days


#1 posted 792 days ago

One of the best tutorials I have seen on greenwood turning.
Thanks for sharing.

-- Scott Smith, Southern Illinois

View xwingace's profile

xwingace

204 posts in 1214 days


#2 posted 791 days ago

Awesome information—you’re inspiring me…

-- I'm not as good as I once was, but I'm as good once as I ever was.

View tyskkvinna's profile

tyskkvinna

1308 posts in 1611 days


#3 posted 791 days ago

The Woodturning Guild I am part of generally prefers to turn green wood, which I find fascinating. I prefer to turn slightly drier woods simply due to the tooling that I use. (I don’t use a wood lathe, rules are different)

I have a little boat load of green wood so I need to get better at it. I’m going to read through more carefully and take some notes. I will be sure to share what I put into action!

-- Lis - Michigan - http://www.missmooseart.com - https://www.etsy.com/people/lisbokt

View ratchet's profile

ratchet

1285 posts in 2412 days


#4 posted 791 days ago

Robert. Dude…you rock! This is an very well detailed and thoughful expose into your experience in greenwood turning. Many thanks for putting this together. Favorited, printed, and saved.

View Bluepine38's profile

Bluepine38

2876 posts in 1711 days


#5 posted 791 days ago

The green wood bowls I have turned, I rough shaped the form and placed the bowls in sawdust for a few
months to dry, then finished them. I will now have to rethink my ideas and try your shortened time process.
Thank you very much for sharing.

-- As ever, Gus-the 75 yr young apprentice carpenter

View RobertJ's profile

RobertJ

26 posts in 1008 days


#6 posted 791 days ago

Thank you for the kind responses. With limited experience, the information and photos I provided must speak for themself. Please remember that the results seem to depend on the type of wood and the shape. I’ve had the worst luck with warping when I cut a rolled-over rim. With a straight cut rim you can wait 3 days and re-cut the rim if you don’t like the shape the bowl has taken. Again, a natural edge is the easiest to deal with but some shapes like the recent painted rim bowls shown truly surprised me. Quite a bit of this is trial and error and I haven’t shown you the bowls that didn’t provide satisfactory results… but it’s only 5 dollars invested in a large chunk of firewood so it seems worth experimenting given that I do get some satisfactory results as shown.

Thanks for your comments!

-- RobertJ, Southern California

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