Cracked my kuksa

[Shewie]

I got a really nice birch kuksa from a member on here a few years ago but I've used it very little. It was always a bit on the chunky side and not really deep enough for a good man brew so I tended to prefer other pots.
I dug it out of the kit pile a few weeks ago and started fettling with it now and then, I mostly took some depth out of the bowl and reshaped the handle slightly, just taking a bit of bulk off it really. After I'd finished with the crook knives and sanded it off I gave it a couple of coats of tung oil and left it to hang for a few days. Tonight I thought I'd have a first brew in it, I made a mug of coffee and left it to cool for a while before pouring into the kuksa. I went off to do something for a few minutes and came back to coffee all over the kitchen top, the kuksa had split in two places with the cracks running about 10mm straight down from the lip.

To say I'm gutted is an understatement, I was really pleased with the way it had come out. I guess I'll have to make another one when I'm out next week.

Is there any way it can be saved, I thought about just filling it in with wood filler but not sure if the cracks will continue to run. I think I might have taken a bit too much off the sides and might have made it too thin in areas. Saying that though I've had it for around four years I think and it was well seasoned when the other member first made it, I wasn't expecting it to split with a bit of warm liquid inside. I also thought it was a bit odd in the way that it split, I would've thought it would follow the grain?

 

[bb07]

Hmm, odd that it would crack now Shewie, that surprises me, but I don't know enough about wood grain to venture a guess as to why it cracked the way it did. The warm liquid was obviously the culprit but why I do not know.
As far as filling the cracks, again I'm afraid I can't help with ideas. In short, I see I'm absolutely no help at all!
All I can say is that I'm sorry to see it crack and offer moral support:sad6:

 

[crosslandkelly]

You could possibly fill the cracks with a mixture of sawdust and epoxy, that should hold them.

 

[JohnC]

This happened to a bowl I'd made, hot soup did the same, I heard a pop as the fibres gave way. I filled it with glue and sawdust, but ened up using it as a bowl for items rather than food.

 

[Zingmo]

Could it be that in storage, the wood had become too dry? Then the hot coffee has caused part of the wood to expand when it got hot and wet.

Z

 

[Gray]

Maybe it expanded too fast with the heat, what a shame,looks lovely.

 

[Dogoak]

I've had this happen, my repair was to drill a very small hole at the very bottom of the crack (as far down as you can see where the wood has or will crack) to stop the crack going further. I then filled the crack and hole with epoxy and then sanded it when it was dry.

Good luck.

 

[Teepee]

Yeah, that can be saved.

Clean the crack with meths, prime the crack with clear liquid epoxy like araldite, leave to go tacky and than fill with epoxy and matching sawdust.

I have some wood coloured thixotropic epoxy left from a job that won't sag out of the crack, say the word and I'll bring some over next week.

 

[Shewie]

Thanks for the suggestions folks

The cracks have almost closed back up again today, I presume as it's dried out. Now I don't know what to do.

 

[addo]

This often happens with kuksa's made from a log that has been split in half along the pith, even when the cup is well seasoned and made, and then hot water put in it. Ive had a few failures.
If you make another try and get a burr, the natural shape helps to stop the cracks happening.

If you use a log instead, get one well oversized, then clean off a few cm of wood from the split face to get away from the close inner rings. When you carve it, carve quick (or plastic bag it in-between sessions) and make the walls as thin as possible, and avoid knots in the work piece to start with. When you dry it very slowly using paper bags etc, add oil onto one side of the end grain of the rim and any knots to try and slow the stresses down a bit.
Another tip if you fill in with pine pitch trying to be natural, it melts. Epoxy works well though, often with a carved splice of wood to fill the gap.

Ive never had a problem with burrs unless very knotty and therefore full of holes, but nearly always had problems with the split log method, when using the kuksa for hot brews.

 

[dave53]

hi shewie what about cutting it down to the end of the crack it will make it shallower but will save you putting anything synthetic in it to repair it especially since you grown attached to it just a thought regards dave

 

[Shewie]

This often happens with kuksa's made from a log that has been split in half along the pith, even when the cup is well seasoned and made, and then hot water put in it. Ive had a few failures.
If you make another try and get a burr, the natural shape helps to stop the cracks happening.

If you use a log instead, get one well oversized, then clean off a few cm of wood from the split face to get away from the close inner rings. When you carve it, carve quick (or plastic bag it in-between sessions) and make the walls as thin as possible, and avoid knots in the work piece to start with. When you dry it very slowly using paper bags etc, add oil onto one side of the end grain of the rim and any knots to try and slow the stresses down a bit.
Another tip if you fill in with pine pitch trying to be natural, it melts. Epoxy works well though, often with a carved splice of wood to fill the gap.

Ive never had a problem with burrs unless very knotty and therefore full of holes, but nearly always had problems with the split log method, when using the kuksa for hot brews.

Thanks for this Paul, that makes a lot of sense. It doesn't sound like I'll be able to use it for hot drinks if it's just going to repeat the splitting.

I have a blob of resin kicking about somewhere, I might try and open the cracks up again and melt a bit in. The trouble is it took a couple of days to seal up again so the resin will have gone off by then, I wonder if I can speed up the process with a hair dryer?

 

[Scots_Charles_River]

Maybe it needs sealed, to avoid it drying out eg over the winter in a house centrally heated.