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I hand-carved my first Kuksa a month ago from half an ash log. I worked with semi-dry wood (definitely not green, but still wet). I used axe, Japanese gouge and knife and all went well. The bowl is not too thick either.

So I let it dry in a plastic bag opened in the bowl and after some (short) drying I put linseed oil on it and let it dry more. I was quite surprised because it was absorbing so much linseed oil. A bit like a sponge... After two weeks of drying and the final application of a mixture of beeswax with linseed oil and some more drying I tested it with some warm tea.

To my disappointment I got a lot of linseed oil floating in my bowl. Then I let the tea in the bowl for some time, to see how it holds. In very little time tea began to ooze from the pores on the outside of the bowl in the faces that were cut across the grain. Then the bottom which was getting wet from this has split.

So I guess my mistake has been to not let the wood dry out completely before oiling and that the oil somehow has caused the wood to contract, somehow keeping the pores open.

Am I guessing right? Or is the ash really spongy like this and not suitable for bowls? Or have I overlooked something. Sorry I'm only starting with bowl carving...

I would like to add that I haven't got this issue with a well-dried beech bowl.

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  • I don't know about ash, but some kinds of wood do have open pores that would make them unsuitable for use as a vessel unless those were sealed with something more resistant than oils and wax. Finishes can flow right through these woods rather than sitting nicely on or near the surface, and water can do likewise unless some kind of barrier is established. The fact that the wood soaked up so much oil might have been a warning that this was an open-pored wood.
    – keshlam
    Commented Mar 20, 2016 at 2:35
  • Are kuksa usually oiled? I can't imagine they are because oil is actually a terrible waterproofing agent for wood. In terms of using linseed oil, even if you used BLO (with added drying agents) it still takes weeks or a month or more to 'dry'. If you used raw linseed oil the curing period is measured in months, not days or weeks and it won't progress properly at lower temperatures (why oiling furniture was traditionally left for warm weather).
    – Graphus
    Commented Mar 21, 2016 at 12:35
  • I did a non scientific test with a plane and some ash in the shop. The shavings I got seem to be a little more solid than oak, but break up at the growth ring. I did not get a shaving ribbon as much as a group of them loosely held together at the growth rings. My conclusion is that the wood is pretty porous. I also saw several references to ash online as being porous.
    – Ashlar ♦
    Commented Mar 21, 2016 at 14:48

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I hand-carved my first Kuksa a month ago from half an ash log.

There's your problem. Kuksa's are best made from a close-grained wood (traditionally birch burl). Ash, being open-grained, is very subject to seepage like you described.

I would like to add that I haven't got this issue with a well-dried beech bowl.

This makes sense since beech is close-grained. I would imagine that maple and cherry would make a good kuksa for the same reason. Red oak would not. Black walnut has some chemicals that I might not want dissolved in my tea (and its grain is a little open too).

So I let it dry in a plastic bag opened in the bowl and after some (short) drying I put linseed oil on it and let it dry more. I was quite surprised because it was absorbing so much linseed oil. A bit like a sponge...

Again, since ash is open-grained, the exposed end grain will soak up oil like a sponge. Also, are you talking about boiled linseed oil (commonly called BLO) or flax seed oil? They are essentially the same thing, but flax seed oil is considered food-safe. I wouldn't use BLO on something intended to hold hot liquid that I will drink.

If you're looking for more information on finishing a kuksa, I'd recommend having a look at this site. Jeff Ballantyne has a YouTube channel as well that has a lot of good information on kuksa and spoon carving.

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  • Yes, the wood species is the problem on this one!
    – bowlturner ♦
    Commented Mar 21, 2016 at 17:00
  • Thanks I didn't know this ! Is there somewhere a list of close grained wood OK for containing food? I used edible linseed, from the local organic food store.
    – Joel.O
    Commented Apr 20, 2016 at 17:31

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