Wood Glue

[Syd Sellers]

I have a question for all you turners that Laminate and create Segmented turning blanks.
What glue is the best?? The reason I ask is that I make a few goblets that are made with a glued up center core with larger pieces glued onto the core.

After several months after the turning and finishing is done, you can feel the glue migrating out of the joint. Is this bad glue or bad technique?? The wood was dry cherry and dry hard maple. The glue I used was milk based LePage wood glue outdoor. It says it's water resistant that's why I used it for goblets.

Any clues???

 

[john lucas]

There have been some good discussions on this on the segmented woodturners site. Most of them use yellow PVA woodworkers glue. the secret apparently is to let the moisture in the glue that migrates into the wood completely dry before turning. The moisture swells the wood slightly. If you turn it too soon when the moisture comes out the wood shrinks and the glue sticks up.
You could also have different skrinkage and expansion rates of the two woods that joint each other but usually that's felt as a slight bump different than a raised glue bump.

 

[Dick Sowa]

John said it right...it's not the glue, it's the wood that is shrinking that creates the problem. That introduction of moisture does really swell the wood slightly. The same effect has been seen with those using biscuits in flatwork projects. The wood telegraphs the shape of the biscuit, because sanding and finishing happened well before the moisture escaped. The solution is to turn your vessel, then let it sit for several weeks to let the moisture equalize. Then go back and touch it up before finishing.

As far as segmenting goes, I prefer plain old Titebond original. While not waterproof, it does penetrate the wood, makes a super strong joint, and best of all, it retains some flexibility. CA and plastic resin glues are way to brittle when dried. Since you are dealing with small pieces, you want maximum flexibility in the glue to accommodate wood movement.

An alternative, which I have found works pretty well for small projects, is epoxy. Epoxies are also pretty flexible, and have the advantage of being waterproof, and won't swell the wood. The disadvantage, of course, is that it is really messy.

 

[MichaelMouse]

I have to say that "several months" should have allowed the wood to fully equalize. after the initial application. So I'll offer the other solution - creep. one of the characteristics of a good wood glue is its ability to creep, or give a bit when the wood responds to moisture changes. Preserves the joint rather than breaking. I'd say that the wood is moving in response to the atmosphere, but the glue not moving at the same rate.

Overnight is the standard cure time recommended in carpentry to prevent guttering along the joint. What happens is rather the reverse of what others have said - since the wood swells at the joint, it, and the glue that holds it can be planed away, resulting in a depressed area. You don't get the glue proud of this surface, because it was cut away along with the wood.

Remember that you have permanently bulked the wood fiber at the glueline by filling lumens with glue, so unless you have a reasonably even ratio in the response to change, you'll occasionally see the lines proud of the surface.

 

[Gynia]

There are many glues which do not permit creep. Epoxy, Tightbond original, hide glue and resorcinol glue to name a few.

 

[Syd Sellers]

How long do you wait?

I have to say that "several months" should have allowed the wood to fully equalize. after the initial application. So I'll offer the other solution - creep. one of the characteristics of a good wood glue is its ability to creep, or give a bit when the wood responds to moisture changes. Preserves the joint rather than breaking. I'd say that the wood is moving in response to the atmosphere, but the glue not moving at the same rate.

Overnight is the standard cure time recommended in carpentry to prevent guttering along the joint. What happens is rather the reverse of what others have said - since the wood swells at the joint, it, and the glue that holds it can be planed away, resulting in a depressed area. You don't get the glue proud of this surface, because it was cut away along with the wood.

Remember that you have permanently bulked the wood fiber at the glueline by filling lumens with glue, so unless you have a reasonably even ratio in the response to change, you'll occasionally see the lines proud of the surface.

So after the glue up job is completed, how long should one wait? It sounds like you should wait for everything to dry completely. I'm sure this is my problem. I am a little impatient to get at it. In most cases, I glue up one day wait over night and turn it the next day.... I'm sure that with a water based wood glue, drying will take a lot longer than this... I will monitor this on my next glue up job and see what the moisture content is down to before I give it a go.
Thanks so much for all the input.

 

[MichaelMouse]

The glue and the damp glue line are fine after 12-24 hours. Your problem is not poorly cured glue, it's perhaps the type of glue. Been a long time since I used a casein-based glue, even though Elsie is still on the label, so I can't say for certain that it's rigid glue lines and wood movement. I can say that if your glue lines seem proud of the surface, it is not because they were poorly cured. Had they been, your turning and sanding would cause them to show as depressions. The woods you mention are close enough in shrinkage that they are probably not your problem. If you're using the goblets to drink out of, you might be softening the glue enough that the wood squeezes a bit up to the surface in places. Too many variables to do anything but rule out.

 

[Scott Miller]

Most of the wood glues available (like tilebond) have an effective shelf life of 1 year from the date first opened. They say it is still usable as long as it has not changed color and is still liquid but you are taking your chances.

 

[Malcolm Tibbetts]

Wood is constantly moving; either expanding with moisture addition (glue or humidity) or shrinking due to the loss of moisture. I don’t like the term “glue creepâ€; it seems to put the blame on the glue. I prefer to think of the problem as the “inch worm effectâ€. When the wood expands, some of the glue travels with it, but when the wood shrinks, the glue does not always travel back inside the glue joint – think of “path of least resistance.†Things will always move in the path of least resistance, so the tightness of the glue joints resist the glue from returning into the seam. Waiting for a “full cure†will solve the problem of glue moisture, but long term, seasonal humidity changes can result in tiny ridges. The solution: wait at least a few days before doing final sanding and finish application and do a good job of sealing the wood to minimize the effects of humidity changes. I really love wood, but hate the fact that it so easily moves.

 

[Will Hunt]

Try Urea Formaldehyde

I've had the same problem. I checked with the Titebond people and they confirmed the "creep problem". UF adhesive is primarily used for veneering. It does not have the expansion/contraction flow like the PVA's. It can be had in white, Natural (grey) or dark (think mahogany). It is a two parter that is very easy to use. I get mine (Unibond 800) from Vacuum Pressing Systems in Brunswick ME --207-725-0932.

Will Hunt

 

[odie]

Now that we're on the subject of wood glue......Specifically Titebond:

I've been using the Titebond since the late 1980's, and everytime the "new and improved" formula comes available, I've switched.

I'm currently using the Titebond III for all my wood glue application. I guess I've been suckered into changing, because the advertising always says it's "new and improved"......but, I'm not really sure if I should have bothered.

Sometimes, I'm using the Titebond dark glue, but I think that one is actually the II formula.....anyone know about that?

One solution to a problem I have had is it seems the newest version III might adhere better than it's predecessors, with colder temperatures. This time of year, I always keep a small ceramic heater going 24/7 in the shop, but it's only purpose is to keep the temperature above around 40 degrees, or so. When I'm physically in the shop, I keep the temperature closer to around 70-75 degrees.

Whatever I'm gluing, it MUST be done while I'm still planning to be in the shop for awhile.......or, take my chances that the bond won't be as strong as it should be. It seems like once the glue has began to "set", or harden, then the temperature no longer becomes a relevant factor......This is an extremely important consideration for me, because I use waste blocks for mounting bowls, and I've had a couple of them separate at the seam while the lathe is running. This hasn't happened for some time now, but as long as a couple basic rules are understood and followed, the problem becomes non-existent.

Anyone else gluing up wood under similar circumstances? Your findings?

ooc

 

[Syd Sellers]

UF verses PVA glue.

Odie, I'm still in the dark ages with my choice of glues. I have not done much glue up for the past 25 years or so and all my glues are old... I didn't think that they had a best before date but when I opened up my UF glues and mixed it up, it dried to a powder very similar to what I started with so it's dead. My Titebond II is at least 15 years old so it's history too I guess, so I'm on the hunt for a good glue.

It seems that UF glues are no longer available in Canada or at least in my area, so the hunt goes on.

Knowing now that these glues have a shelf life, I will make sure to get small amounts not gallons.

How long has Titebond III been out?

 

[Malcolm Tibbetts]

Syd, Titebond Original is still the most common choice with segmenters, although the other Titebonds are also good glues. The III is very good but it's more expensive and it dries darker which will create a darker glue line between light-colored woods.

 

[Syd Sellers]

Glueing Manitoba Maple/Box Elder

Syd, Titebond Original is still the most common choice with segmenters, although the other Titebonds are also good glues. The III is very good but it's more expensive and it dries darker which will create a darker glue line between light-colored woods.

Thanks Malcolm, this is good to know, at present I'm working with a very light colored Manitoba Maple/ Box Elder so I will stick with the tried and true original.

Thanks.

 

[odie]

Thanks Malcolm, this is good to know, at present I'm working with a very light colored Manitoba Maple/ Box Elder so I will stick with the tried and true original.

Thanks.

Syd.....that's probably the best "game plan" for you, considering Malcom's advice (and he's a master at laminating).

For me, all I'm interested in is pure strength, and working under cold temperatures that my glue joints are sometimes subjected to. Since my application is strictly waste blocks glued to the base of a bowl blank, and that waste block will be cut off in the final step, my priorities are not the same as yours and Malcom T's are......

For what it's worth, I did do quite a lot of laminating at one time, but it's been 15+ years since I last spent much effort with it. I believe back then I used nothing but the original formula Titebond for all the laminating I did. Most of those bowls were sold, or used as gifts, and I no longer know how well they fared......but, I did give a few of these to my Parents, which they still have. I've noticed that some of the laminations have shifted quite a lot, while others seem to have been stable. Those were made in Montana, and my parents lived in Nevada......so, the change in climate could have something to do with it, too.

BTW: The Titebond III has been on the shelves for at least two or three years.......and, unless you will be doing a LOT of laminating, it isn't worth buying in quantity. I threw out one gallon of the original Titebond about ten years ago, because it froze. Also tossed out another gallon of the original Titebond a few years ago because it was coagulating. Since then, I've been using the Titebond II, and now the Titebond III, in small pint quantities..........

good luck



ooc