Green Pen Blanks cracking

[paul269]

For those who make pens, do you have problems with the green wood cracking as it dries?

I went to the local Woodcraft shop to buy some stock to make a few pens. In the past I have simply used my kiln dried scrap, but decided to check out some of the exotics.

I selected an olive wood but noticed it was green. The employee assured me it was ok to use the green wood for the pen and that cracking or shrinking was not an issue. Against my better judgment I turned the pen about a month ago and now it has a crack.

The wood was finish with BLO, CA, buffed then wax applied.

It was a nice pen, I think I will stick with the dry wood.

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[fjimp]

I purchased Bethlehem Olive wood for pen blanks. One of them was a truly special piece of wood. I noticed a hairline crack in it when I was delivering it. It was a gift for my Pastor. I have aksed him about the crack. He tells me it is my imagination. Then confesses he has never owned such a beautiful pen and wouldn't part with it if it was cracked. Jim

[Greenvilleguy]

Random thoughts:

I have turned pens from wood that wasn't kiln dried. It has been from green (wet) wood pieces that have been in shop for months, so I guess you could say they were air dried.

Its odd that the crack doesn't appear to be along the grain lines.

I'm assuming you glued in a brass tube. You would think that the tube would provide support provided the glue was evenly distributed. (I use gorilla glue instead of CA, it seems to spread more evenly.)

After turning, the wood itself is so thin; you wouldn't think that it would crack due to drying.

Is it possible that you got the wood wet when glueing in the tubes and then it dried after turning???

In short, I'm at a loss as to what stressed the wood and caused the crack.

[greitz]

Maybe it's a heat issue in combination with the moisture problem? I've never used olive wood, but I have had tulipwood blanks crack when drilling them. (I think I wasn't clearing the chips well enough and it got too hot.) Also, the Woodcraft people have told me it's important to either turn the speed way down when sanding, or else use very light pressure, because sanding those thin blanks can heat them up quickly.

Gary

[charlese]

Just a note, also randomly:
We sometimes get surprised when defects in wood occur after our careful labors to make a piece. Really it's a no brainer. Don't try too hard to come up with other reasons or causes. The cause is most usually a result of the normal drying and shrinking of wood. If the workpiece is thoroughly dried to reach equilibrium with your shop/house prior to milling, wood pieces it will not split because of drying. This is why a moisture meter is such a valuable shop tool. Of course these meters won't work with accuracy on small pieces like pen blanks. Here, we need to rely on time. Three weeks is not unreasonable.

I would also like to observe that splitting hardly never occurs along grain lines, but perpendicular to them. This is because of the greater tangential wood movement. If splitting occurs along grain lines the wood had developed some type of ring shake, way prior to your ownership of the piece.

[a1gutterman]

Random thoughts:

........... (I use gorilla glue instead of CA, it seems to spread more evenly.)...............

In short, I'm at a loss as to what stressed the wood and caused the crack.

I have never turned a pen, so I am completely out of my element here, but I have two thoughts, please forgive me if they are out-of-line:

1)Could you have put something in the wood sleeve that was too big and stressed the wood which finally split? or

2)Is it possible that an expanding glue, like Gorilla glue, caused the wood to split?

[solicitr]

2)Is it possible that an expanding glue, like Gorilla glue, caused the wood to split?

That seems to me a very likely explanation. The polyurethane glues foam up and expand a lot.

[paul269]

Thanks for the input.

I used CA to glue the tube in the blank. Again, I have never had any issues with a kiln dried blank cracking, only this one green blank. Plus the pen cracked about three weeks after it was turned.

I think I will stick with dry wood.

[charlese]

...I think I will stick with dry wood.

GOOD IDEA!