My Bowl Cracked!

[James Farrow]

Well guess what. My bowl cracked. It was sitting on the bench with the face plate still on it and it cracked by itself. Just noticed it. The crack is about 1 1/2" to 2" long. Running down the side both inside and out.

Here's pics:





I guess the wood was not completely dry when I turned it. Oh well, it was fun learning on it anyway.

How do you tell if wood is dry? Or still a bit wet inside?

James

[Chris Rolke]

i turn wet and take it down to less than 1/4" and it typically will just warp and not crack

[Ken Fitzgerald]

On the bright side James....look at all the stress from which you released it!

[Dick Parr]

When that does that to me, I put a couple of drops of CA glue in the crack to stop it from going any further and wait to see if it can be fixed. A crack that small you can add some kids glitter and CA glue to fill the crack. Fill the crack first and then add the THIN CA glue. You can use a piece of paper as a backer and then turn the paper off when you clean up the glitter.

Just a thought to save the bowl.

[James Farrow]

LOL!

Hey, I heard it happens to everyone so might as well get it out of the way early. And if it is going to happen, better to happen on a $1.00 blank than on something I paid a lot more for.

James

[James Farrow]

Dick, I don't think that trick will work on this one. Just looked at it again and there are numerous hairline cracks showing up on the outside all running the same way as the larger one. I have a feeling it's not finished cracking yet.

James

[Richard Allen]

Don't you just hate it when that happens.

Fortunately wood grows on trees. Good luck on the next one.

[James Farrow]

LOL! That's true.

Oh, so is there anyway to tell if wood is not completely dry.

This blank seemed dry, the shavings were dry and the sawdust
was dry, but obviously it wasn't.

Or is it just "pot luck" when getting these "who knows where this came
from" blanks?

James

[Rick Prevett]

James, it could be that you overheated the wood during turning. You say the sawdust was dry. If you're makin sawdust, you might be running a dull tool thats heating/drying the cutting area. It dries first, and creates cracks. I think thats happened to me a couple times.

rick

[James Farrow]

The sawdust came from sanding it. Didn't seem to get hot although I was using that soft backed sandpaper that comes in rolls so maybe it was getting hot and I just couldn't tell.

Will check that on the next one.

James

[George Tokarev]

One thing you can do to help your cause is not make the walls so vertical. Second thing is to keep the sapwood down. The clearer pictures look like red oak, rather than the beech I thought it might be, but they both will split along the lines of the ray figure. Oak just stinks more when you cut it, and rusts everything it touches.

Anyway, sapwood, the white stuff, contains proportionally more moisture, thus contracts more in proportion to heartwood. You see this on firewood with radial checks, on sawn wood, where the curve "frowns" toward the outside of the tree, and on quartered, or nearly quartered wood, where you get a concavity toward the sapwood side of the board. Nature of the beast.

Turners normally like to have the sapwood out, for a number of good reasons, not the least of which is that you get best diameter from a log that way. Additional benefits accrue when your hollowing shows wider figure, when you trim away most of the sapwood to get a bottom mount, taking away a bit of the pull, and, of course, the bottom is normally smaller in diameter than the top, which further reduces the drying stress. Green wood turners are all too familiar with the dropping of the sides and the contraction across the grain which can cause splitting near the heart if they leave too many of the tight annual rings.

They also have seen, but may not readily recall, the effect of tapering inward and relieving stress in another way. I leave my roughs about an inch thick in a dozen, and even though the rim starts out flat, the inside edge of the looks elevated when it dries, because the wood has relieved its stress by bending into thin air. Vertical sides don't allow for this.

Now that you know, have at it again.

[James Farrow]

Thanks!

James

[Andy London]

James, If you have a lot of small hairline cracks, it is more than likely due to heat, slow the mini down to the slowest speed when sanding, power sanding also helps.

[James Farrow]

Thanks!

I have it on the slowest (500 RPM) speed. And I kept moving the sandpaper.
Next time I will check to see if it heats up.

James

[Richard Allen]

How can you tell if the wood is dry?

Kiss it.

You need to kiss uncoated wood. So if you mount the blank and turn off any coating that might be on the blank you will have bare wood.

Your lips are very sensative to moisture and tempature. If you put your lips to the wood and it feels cool it almost certinaly has more moisture to release. If the "kiss" feel warm or no temp then the wood is very likely dry.

You can use a moisture meter but there are issues with moisture meters and bowl blanks.

You can weigh the wood over a a period of weeks and see if there is any change in weight. A change in weight indicates that the piece is losing moisture.

Bowls can crack for a lot of reasons.

So get "friendly" with your turning stock.

Richard