Novice turner question

[Jim Tobias]

I have turned a little but nothing involving gluing blocks of wood together. I am planning to glue 2 pieces of wood(Jatoba and Walnut) to give me a thicker and wider top for a box. I will probably dye it black when finished. Using these 2 woods because I have the necessary width/thickness on hand. As long as I glue with grain running perpendicular to each other, I shouldn't have issues, right?? I know the Jatoba is tough on cutter,etc. But again, I have it in my stock .
Thanks in advance for any advice.

Jim

[David Dockstader]

Jim,
I think you mean "parallel," not "perpendicular." Perpendicular would mean you are gluing one piece with end grain, the weakest possible glue joint.

[Dave Mount]

Despite what you see in plywood, you generally want the grain running in the same direction, not perpendicularly. I'm assuming these pieces are thicker than 1/8" and more than a couple inches wide/long. Below those dimensions, you might get away with cross grain lamination. The idea is, you want the woods moving in the same directions. When you laminate dissimilar woods, you can sometimes get some distortion seasonally if they have different degrees of expansion/contraction with moisture. The bigger the pieces, and the more dissimilar the woods, the more you invite problems. Another variable is how permeable the finish is to water vapor. You can Google up charts of relative movement for different woods to see how similar your two are.

Best,

Dave

[John K Jordan]

I have turned a little but nothing involving gluing blocks of wood together. I am planning to glue 2 pieces of wood(Jatoba and Walnut) to give me a thicker and wider top for a box. I will probably dye it black when finished. Using these 2 woods because I have the necessary width/thickness on hand. As long as I glue with grain running perpendicular to each other, I shouldn't have issues, right?? I know the Jatoba is tough on cutter,etc. But again, I have it in my stock .
Thanks in advance for any advice.

Jim

Hi Jim.

(Hey, you posted another nearly identical message with the same title. You want it deleted to avoid fragmentation?)

You can glue the boards with the grain parallel or perpendicular (like plywood) but due to the natural movement of the wood the parallel might be a better idea. However, it the movement probably won't matter much if the piece is turned to a relatively thin wall.

Also, in my experience, Jatoba is not particularly hard on turning tools. I've used a lot of it for a variety of things.
433399

I carefully flatten each layer of the sandwich either with the drum sander or with a big sanding stick on the lathe. I use Titebond and clamp well and let dry overnight. This is how I clamped at first:

433400

This is how I clamp now - much quicker and the book press (mounted to a support) provides a LOT of pressure. (It's surprisingly affordable, too!)

433401

Some pieces ready to be glued. Note the pre-hollowing before gluing which makes deep hollowing much easier.

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Some people clamp between the headstock and tailstock of the lathe but I only tried that once.

BTW, my very first bowl about 20 years ago was from several layers of 4/4 red oak board glued up since that was all I had in my shop! Worked fine. Here are some more recent glueups, Beads of Courage boxes and one goblet.

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I've glued up a LOT of things from a variety of 4/4 and thicker. I always put the grain of each layer parallel to the next layer. BTW, you can glue up end grain to end grain if you put a layer of side grain between - that's the way I did the goblet. This advice is from Frank Penta, an expert in glueups! He has four or five pages of turnings from glueups on his web site.

If you have any questions, call up Frank and ask! I guarantee he will stop what he is doing and help a stranger - that's just the way he is. :) Tell him I said "Hi".

http://www.frankpenta.com/index.php/gallery/category/39-laminations-2015?start=20

[Jim Tobias]

Thanks for the replies. Dave, Dave and John,
Yes John, if you can delete one of the posts that would be great. I did it from my mobile phone and it did not show it as being sent initially.
I should have been more descriptive in my initial post. I glues the two pieces face grain to face grain but with the grain lines running perpendicular to each other. The walnut is about 2" thick and on top...….the Jatoba is about 1 " thick and on the bottom. The Jatoba portion will end up being maybe 1/2" thick at most as it will taper up into the walnut which is giving me the necessary height to have a rounded/domed top.
It is glued together so I may just turn it and wait awhile to see what happens. Both pieces of wood have been in my shop for many years and the temp/humidity is controlled so it has to be dry.
Any best guesses at this point?

Jim

[John K Jordan]

Yes John, if you can delete one of the posts that would be great.


OK, I moved the one reply to the other post here and deleted the other thread.




I should have been more descriptive in my initial post. I glues the two pieces face grain to face grain but with the grain lines running perpendicular to each other. The walnut is about 2" thick and on top...….the Jatoba is about 1 " thick and on the bottom. The Jatoba portion will end up being maybe 1/2" thick at most as it will taper up into the walnut which is giving me the necessary height to have a rounded/domed top.
It is glued together so I may just turn it and wait awhile to see what happens. Both pieces of wood have been in my shop for many years and the temp/humidity is controlled so it has to be dry.
Any best guesses at this point?


My best comment is to wait and see what happens! Fortunately, both are relatively stable woods compared to many:
Walnut - Shrinkage: Radial: 5.5%, Tangential: 7.8%, Volumetric: 12.8%, T/R Ratio: 1.4
Jatoba - Shrinkage: Radial: 4.2%, Tangential: 8.0%, Volumetric: 12.1%, T/R Ratio: 1.9.

Look at some of the others:
Holly: Radial: 4.8%, Tangential: 9.9%, Volumetric: 16.9%, T/R Ratio: 2.1
R. Oak: Radial: 4.0%, Tangential: 8.6%, Volumetric: 13.7%, T/R Ratio: 2.2
A Beech: Radial: 5.5%, Tangential: 11.9%, Volumetric: 17.2%, T/R Ratio: 2.2

I would try to keep the humidity as constant as possible until the wood is turned and a good sealing finish applied. It's not necessarily how dry the wood is now but how much it changes dimensionally when it gains or loses moisture. If the turned walls are not too thick, each piece will likely flex a bit as the humidity changes but stay together. A learning experience either way for all of us - be sure to report back!

My best guess is it will be fine. I've made a few pretty wild combinations over the years and

JKJ

[Pat Scott]

For what you're doing you'll be fine gluing them up perpendicular.

[Prashun Patel]

It's not ideal for them to be glued perpendicular. But to be honest, all bowls are essentially cross grain-bound situations. That's why they warp and move even years after drying. You'll maximize your changes for success by turning to a consistent thickness, and on the thinner side. My thinner, green forms tend to warp; thicker tend to crack. I do not know if this extends to cross grain glue ups.