Kuksa

[Northwolf]

Hello everyone!
I'm new to this forum so happy to start being part of this community.
Recently I started carving kuksas and sometimes I have problems with cracks.
The last one I made it out of a dry nice piece of beech. Dry wood is the only I have available at the moment. It worked very nice and smoothly. After finisihing it, I left it in a plastic bag for a few days. It looked completely dry and very solid. So I put beeswax. Then I wanted to start filling it with liquid and so I poured a bit of cold water. After 3 or 4 minutes the kuksa cracked on the outside with a main long horizontal crack and other cracks... it was unexpected and felt very sad. I'm not that experienced in kuksas and I tried to read and watch whatever I could but have not found an explanation for this. Can anyone help?
Thank you

 

[SoldierPalmer]

Try using walnut oil before adding any liquids. A good few soakings so it’s all in there. Think of wood like little straws. The oil will fill these straws and prevent the water from getting in and expanding and shrinking the wood.

 

[Northwolf]

Try using walnut oil before adding any liquids. A good few soakings so it’s all in there. Think of wood like little straws. The oil will fill these straws and prevent the water from getting in and expanding and shrinking the wood.

Thank you very much for this advice. I just bought mineral oil. Is walnut oil very different?

 

[Robson Valley]

Welcome. After 20+ years, I'm a novice wood and stone carver.

Kuksa are carved from birch burls for a reason. The twisted grain is so tightly interwoven that the piece is knitted together and can't crack.
Cracking relieves mechanical stress in one direction or another as the fresh wood dries to an equilibrium moisture content like the local atmospheric conditions.

True, sometimes, you can find a block of seasoned wood with no cracks. Nothing to say that repeated hot drinks won't add enough water that it will crack someday. Too bad but for dead stuff, wood moves.

 

[Zingmo]

I feel your pain. I have come to believe that some kuksas (kuksae?) are destined only ever to hold peanuts. That being said here's my two penny worth.
The splits occur at certain places. So be careful with the axe near where the handle joins the bowl. And leave extra thickness at the side opposite the handle. I don't think it's a coincidence that my surviving kuks all have a protruding point opposite the handle like the prow of a boat.
The rim needs to feel thin to be comfortable to drink from, but needs to be thick enough to avoid cracking. Fake the thinness by sloping the outside of the rim inwards without thinning the whole wall. Undercut the inside at the edge as much as your tools allow.
It may be internet folklore, but I also have followed advice to boil the kuksa in salt water before your finishing cuts to "relieve stresses in the wood". It hasn't done any harm so I keep doing it.
I tried filling one with boiling milk: It split. I cried but not over the milk...
A canoe cup ditched hot coffee all over the place on its inaugural outing...
A noggin leaked single malt straight through into my lap...
You just have to get back in the saddle and get carving the next one.

Anyone need a peanut bowl?

Z

 

[TLM]

Boiling in water and boiling in salt water are the two commonly used methods of trying to prevent splitting. Soaking in a ketone is one efficient way but not used very often.

 

[quietone]

Hey. I feel your pain. One of mine split, probably due to a poor choice of wood. I only ever use burls now. As Robson Valley eloquently put it, burls are perfectly suited to wooden cuperware. Our ancient ancestors found the benefits of using a burl, although its a tricky carve, even when very green. Even then there will be a little shrinking and warping as it dries. Keep at it, it'll all fall into place as you get more experience. Kuksa carving is very rewarding and the learning curve is intuitive. Next birch burl I get, I'll post it to you if you like.

 

[punkrockcaveman]

Personally, I would say seasoned wood is probably littered with tiny fractures just waiting to pop. I've not carved a kuksa but I've had it happen with spoons from seasoned wood- cherry and birch. I'd try green wood if you can help it