Are there any issues when gluing up segmented blanks that contain some of the oily exotic species?
-
January Turning Challenge: Thin-Stemmed Something! (click here for details) -
Conversations are now Direct Messages (click here for details) -
Congratulations to Scott Gordon for "Orb Ligneus" being selected as Turning of the Week for January 20, 2025 (click here for details) -
Welcome new registering member. Your username must be your real First and Last name (for example: John Doe). "Screen names" and "handles" are not allowed and your registration will be deleted if you don't use your real name. Also, do not use all caps nor all lower case.
Question for segmented turners
- Thread starter Tom Cadwalader
- Start date
- Joined
- Apr 27, 2004
- Messages
- 9,089
- Likes
- 5,641
- Location
- Lakeland, Florida
- Website
- www.hockenberywoodturning.com
Tom,
Only a few experienced segmented turners on this forum
Andy Chen is exceptional and may answer. I'm sure there a few others too.
There is a virtual chapter of the AAW dedicated to segmented turning.
They meet in the Internet and have an occasional symposium for segmenters.
If you want to pursue segmented turning I suggest you take a look at the
The segmented chapter of the AAW
http://www.segmentedwoodturners.org
Al
- Joined
- Jan 27, 2005
- Messages
- 13,040
- Likes
- 5,483
- Location
- Dalworthington Gardens, TX
- Website
- pbase.com
Also, Malcolm Tibbetts' book, "The Art of Segmented Woodturning" is a great resource. He also has a number of DVDs and some online videos on his website.
john lucas
AAW Forum Expert
I've only done a fair amount of segmented turning over the years and most have been local woods. I have however worked with a fair amount of exotics in glue ups that became turnings such as my hand mirrors. I try to wipe them down with acetone also although I know I've glued up a fair amount without doing that. If it's a really oily wood like cocobolo I do try to do that before applying glue. So far the only failure I've had was not due to the glue but excessive wood movement. I thought it might be a problem and kept the piece. Sure enough about a year or so into it's life I got some movement at joints where you could feel the difference in height. Then another year or two and I got some separation. Still the glue actually held on 80 percent of the joint. I don't think any glue would have held up for the whole thing.
John,
When you said you had wood movement was it the cocobolo that moved or was it the other wood glued to it. The reason I ask is I am taking carving classes from a guy who traded out some work for some cocobolo chunks that's probably 10-15 years old and I'd like to buy a chunk or two from him and try my hand at using some of it just for accent in a piece. Would something this old still be oily?
Jeff
When you said you had wood movement was it the cocobolo that moved or was it the other wood glued to it. The reason I ask is I am taking carving classes from a guy who traded out some work for some cocobolo chunks that's probably 10-15 years old and I'd like to buy a chunk or two from him and try my hand at using some of it just for accent in a piece. Would something this old still be oily?
Jeff
The simple answer is -- never rely on a glue joint for ANY oily wood. This includes Cocobolo and most of the rosewoods. Wiping with acetone or other solvent just delays the problem. The oil will weaken the joint eventually.
- Joined
- Jan 27, 2005
- Messages
- 13,040
- Likes
- 5,483
- Location
- Dalworthington Gardens, TX
- Website
- pbase.com
Jeff, the answer that applies to any glue joint between dissimilar woods is that movement occurs in both of them, but the amount of movement is not the same for each. The solution involves several things:
- Use wood species that have similar movement properties with changes in environmental conditions
- Make certain that the two pieces of wood are stabilized to EMC before they are glued (kiln dried wood is more stable than air dried)
- Some oily tropical woods take many years to air dry
- Smaller segments are generally less problematic than large ones
- Keep the finished product in a stable humidity constant temperature environment
My only experience with dissimilar woods comes from flat work, but ti should be applicable to segmented turning.
Last edited:
john lucas
AAW Forum Expert
Jeff Here are some photos showing how I tried to solve the problem of gluing Cocobolo together. I glued the segmented ring together with epoxy. After it dried I drill 1/8" holes at an angle to the joint and glued in Brass pins. This whole ring was then glued onto the top of a Bowl From Board project. I had aligned all the grain on the BFB which meant it would have wood movement mostly in one direction with just a little long grain movement. As I said after about a year or two the top ring separated from the maple bowl along 2 side grain segments. During the summer months it swells and you can't feel the joints but during the winter there is a pretty noticeable gap along 3 of the top segments joining the maple. This piece is now about 5 or 6 years old and I notice that one of the pinned cocobolo joints has now failed.
Most of the time when i glue oily woods to something else I have a good mechanical joint if possible. On segmented pieces i glue them long grain to long grain and have overlapping joints so the butt joints aren't a problem. When gluing designs into my mirrors the wood is usually captured it grooves or dovetails so it's not dependant on the glue to hold. Still I know I've done smaller bowls with these exotic wood rims and not had problems that i know of. Of course a 6" bowl has much less wood movement than a 14" bowl like the one pictured here.
Most of the time when i glue oily woods to something else I have a good mechanical joint if possible. On segmented pieces i glue them long grain to long grain and have overlapping joints so the butt joints aren't a problem. When gluing designs into my mirrors the wood is usually captured it grooves or dovetails so it's not dependant on the glue to hold. Still I know I've done smaller bowls with these exotic wood rims and not had problems that i know of. Of course a 6" bowl has much less wood movement than a 14" bowl like the one pictured here.
Tom,
When someone mentions oily wood, the first one that comes to mind is cocobolo. The general consensus among experienced segmented turners is DON'T USE IT. I guess I didn't know better and hadn't talked to other segmenters when I used it in some of my segmented vessels. Fortunately, the pieces that contained cocobolo segments have held together so far, at least I have not heard any complaints from those who own them. I am showing a picture here of a lid for a vessel that has twelve segments in the rim surrounding a mesquite burl. It was made seven years ago. You can hardly see the seams and the surface is perfectly smooth without "glue lines". Now this lid is only about 3" in diameter which may have helped it hold together. Over the years, I have used Titebond, Titebond II and Titebond III for gluing my segments. Unfortunately, I have not kept a record of which glue I used on which piece. However, I have never had a failed joint, although you can feel the glue lines on some pieces. I only recently noticed that Franklin, maker of Titebond, claims in ads that Titebond would work on oily wood, but I can't substantiate that. I don't believe in wiping oily wood with acetone and I am skeptical about the notion that the freshly cut oily wood will glue but if you let it sit it will fail.
Cocobolo is such a beautiful wood that it is tempting to use it in segmented piece. However, it darkens relatively fast. The lid in the picture has been kept in a cardboard box (from light) most of the past seven years but it still darkened to the point that you can't tell it is cocobolo. There are many other species that will give you this dark accent but without the concern of failed joint due to the oil content. My advice is to stay away from it.
Sorry I didn't chime in sooner. I was trying to take a picture for the discussion.
When someone mentions oily wood, the first one that comes to mind is cocobolo. The general consensus among experienced segmented turners is DON'T USE IT. I guess I didn't know better and hadn't talked to other segmenters when I used it in some of my segmented vessels. Fortunately, the pieces that contained cocobolo segments have held together so far, at least I have not heard any complaints from those who own them. I am showing a picture here of a lid for a vessel that has twelve segments in the rim surrounding a mesquite burl. It was made seven years ago. You can hardly see the seams and the surface is perfectly smooth without "glue lines". Now this lid is only about 3" in diameter which may have helped it hold together. Over the years, I have used Titebond, Titebond II and Titebond III for gluing my segments. Unfortunately, I have not kept a record of which glue I used on which piece. However, I have never had a failed joint, although you can feel the glue lines on some pieces. I only recently noticed that Franklin, maker of Titebond, claims in ads that Titebond would work on oily wood, but I can't substantiate that. I don't believe in wiping oily wood with acetone and I am skeptical about the notion that the freshly cut oily wood will glue but if you let it sit it will fail.
Cocobolo is such a beautiful wood that it is tempting to use it in segmented piece. However, it darkens relatively fast. The lid in the picture has been kept in a cardboard box (from light) most of the past seven years but it still darkened to the point that you can't tell it is cocobolo. There are many other species that will give you this dark accent but without the concern of failed joint due to the oil content. My advice is to stay away from it.
Sorry I didn't chime in sooner. I was trying to take a picture for the discussion.
Attachments
Thanks John and Bill. I'll stay away from using it in my turning and just use it for carving. It sounds like it would be better to use something domestic and ebonize it so it looks similar to cocobolo if you're going to use it in a segmented piece.
Jeff
Jeff
john lucas
AAW Forum Expert
the only problem with ebonizing or dying for that matter is that you can't turn it afterwords. It just doesn't penetrate deep enough. If it's a lid or something that you can make out of segments and dye afterwords then it works great.
The biggest problem with segmented turning discussions is how many of us keep records of pieces, glue used, how old etc. I made many many small 6" or so bowls about 2 1/2" deep way back. Used all kinds of wood and looking back on what I know now, used techniques that could possibly fail. Those that I've seen are still good, but how many possibly failed down the road that I have never seen. That's part of why I started doing some tests years ago and keep those pieces. An example was pie shaped segmented rings for the bottoms of vessels. I had one blow up while it was in a show. They put it in a glass case and the heat and low humidity did it in. It told me I needed to learn more about wood movement and glue joints. I have since learned how to deal with that problem.
So even though it seems at times that I go to extremes or bring up these wood movement problems its just to make you think and learn. Not saying that what you do will fail because every time I do someone says " I did that and they work fine". There are just too many variables, how the piece is stored, what type of wood, how good the glue is, and how good the glue joints are, etc. Gluing oily wood is another good example. I've had good luck and bad luck (and no luck at all if your into country songs) In the bad cases it's hard to just blame the oily wood but it's still the most likely culprit on those cases.
The biggest problem with segmented turning discussions is how many of us keep records of pieces, glue used, how old etc. I made many many small 6" or so bowls about 2 1/2" deep way back. Used all kinds of wood and looking back on what I know now, used techniques that could possibly fail. Those that I've seen are still good, but how many possibly failed down the road that I have never seen. That's part of why I started doing some tests years ago and keep those pieces. An example was pie shaped segmented rings for the bottoms of vessels. I had one blow up while it was in a show. They put it in a glass case and the heat and low humidity did it in. It told me I needed to learn more about wood movement and glue joints. I have since learned how to deal with that problem.
So even though it seems at times that I go to extremes or bring up these wood movement problems its just to make you think and learn. Not saying that what you do will fail because every time I do someone says " I did that and they work fine". There are just too many variables, how the piece is stored, what type of wood, how good the glue is, and how good the glue joints are, etc. Gluing oily wood is another good example. I've had good luck and bad luck (and no luck at all if your into country songs) In the bad cases it's hard to just blame the oily wood but it's still the most likely culprit on those cases.
Thanks Andy
Thanks for your insight.
Thanks for your insight.
Here’s my take on the subject…
When I first started doing segmented work, I had the pleasure of befriending Ray Allen and he told me that he avoided gluing together rings of just cocobolo. If he used cocobolo, he always inserted another specie in between. I’ve always abided by that advice. Regarding the wiping with acetone, maybe it helps (the jury is still out), but gluing oily woods soon after they are cut will increase your chances of long-term stability. As soon as oily wood is cut, the oily extractive will try to migrate to the surface and that’s what weakens the glue joint. I’ve used many of the rosewoods with success, but I never let fresh-cut segments sit around. Perhaps, even more troublesome than cocobolo is teak; I don’t use it.
When I first started doing segmented work, I had the pleasure of befriending Ray Allen and he told me that he avoided gluing together rings of just cocobolo. If he used cocobolo, he always inserted another specie in between. I’ve always abided by that advice. Regarding the wiping with acetone, maybe it helps (the jury is still out), but gluing oily woods soon after they are cut will increase your chances of long-term stability. As soon as oily wood is cut, the oily extractive will try to migrate to the surface and that’s what weakens the glue joint. I’ve used many of the rosewoods with success, but I never let fresh-cut segments sit around. Perhaps, even more troublesome than cocobolo is teak; I don’t use it.
Thanks, Malcolm. Looking forward to seeing you in Waco soon.