How to minimise shrinkage and cracks in wet wood?

[HappyPixie]

A friend gave me two bits of freshly cut oak with an intriguing stain down its core. I immediately turned a live edge end grain bowl for him out of the smaller bit and wrapped it in a plastic bag before giving it to him. I've suggested leaving it in the bag for the time being but how can I advise him to season it in order to minimise cracking? I'm happy with a bit of warping but I'd like to avoid the cracks that I always seem to see in drying oak. The walls, base and rim are about 8mm thick and relatively consistent.

Since I've got more of this to play with (which I've sealed with PVA) I'm keen to hear your suggestions.

Comments and recommendations warmly sought.

Cheers

 

[RickG]

A more knowledgable person will be along later, but I'd put wood shavings in the bag too. This will help absorb the moisture while you're controlling the humidity with the bag.

I have done this and it does help reduce the splits.

You can also wrap the bowl in newspaper for the same purpose.

Nice bowl BTW!

 

[Stefan999]

nice bowl, I have some greenish oak, might have a go...

 

[John Brown]

That's not a bowl, that's a hat.

 

[Dalboy]

Green wood needs to be turned to roughly the same thickness throughout, if you do it different it will likely split, but having said that even thin turned to the same thickness may still crack. Slowing the dry process may help. If you do pot it into a plastic bag it will need to be turned inside out as moisture will build upon the plastic.
Oak can quite often split easily compared to other woods

 

[CHJ]

Try soaking thin green turnings in Lemon Oil, the moisture in the wood appears to be miscible to some extent in the oil volatiles and results in a more controlled dispersal of the natural wood moisture allowing even controlled shrinkage as the volatiles disperse.

 

[HappyPixie]

Many thanks for the suggestions. I have some lemon oil so I'll give that a go.

Cheers

Steve

 

[Paul Hannaby]

You won't stop the shrinkage but you can minimise the cracking by drying slowly or by turning thin (less than around 5mm) so the wood will distort instead of cracking as it dries.

 

[TheUnicorn]

Just thinking out loud here, as I've never done this, but I wonder whether binding the piece with webbing or similar might give it some structural support as it dries out?

 

[CHJ]

Just thinking out loud here, as I've never done this, but I wonder whether binding the piece with webbing or similar might give it some structural support as it dries out?

No; have no useful effect, wood movement can and will apply extremely high forces.

If you manage to restrain one area another will split as the wood shrinks.
It's the reverse process of Quarry men wetting dry oak wedges in narrow grooves to split enormous multi ton slabs of rock.

Try gluing some wet wood strip scraps, alternate end grain to side grain and see what happens as the wood dries, assuming the glue joints don't let go that is.

 

[ScaredyCat]

I've seen (a couple of times now) people elsewhere suggest putting turnings in a big bag or box of silica gel. Is this likely to work well ?

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