Wednesday, June 20, 2012

Part 2: Bowl cracking

Hi Everyone,

One of the bowls I made several weeks ago has developed cracking along one side of the bowl:

Working with green, unseasoned wood is always a crap shoot because of the drying of the wood.  As the fibers lose water they shrink in size and they also pull away from each other. Coupled with stresses in the wood blank that are caused by turning it into a circle, will cause distortion and at times cracks to appear.

As this crack goes through the wall of the bowl I'm going to have to do some serious first aid on it.
First of all, it will be turned down almost to it's final shape. Removing wood will relive some of the stress in the walls of the bowl. Secondly, it's going to need to be treated with a product called Pentacryl.

Pentacryl is a wood stabilizer that was developed by museum curators to treat and restore old pieces of furniture that will crack over time. It replaces the water in the wood fibers and reduces the amount of movement in the wood as it dries out over time. It's non-toxic and doesn't interfere with the making or finishing of the bowl. It's an excellent product and if you are a wood turner who is reading this I highly recommend it.

Here is the bowl after about 45 minutes worth of turning:

I turned both surfaces of the bowl. Here you can really see the crack. If you look very carefully you can see the crack is radiating from a small knot in the wood:

I'm going to treat the bowl with Pentacryl for the next several days and then place it back in the drying bags for a week or two. We'll see this bowl again. Keep your fingers crossed that this works.


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