Cracks in a log

[PaulH]

I was given a log about 2.5 feet long and approximately 1ft in diameter. I think it is from a fir tree but am not sure. Following advice found on this forum I immediately sealed the ends (using diluted PVA glue, 75% glue, 25% water). After only a couple of days I can see cracks beginning to appear in both ends of the log. They are in the middle of the log and spread outwards.

Is there anything I can/should do to stop these cracks from spreading wider and deeper?

Before sealing the ends I did cut a bowl blank to try some wet turning. I've left the resultant bowl quite thick so that when it's dry I can "finish" it. However, there are also a couple of cracks that have appeared which are widening by the day. Again - is there anything I can/should do to stop this getting worse?

When turning, I encounter several knots (and these are associated with the cracks in the bowl) - does that mean it's basically not suitable for turning? (I hope not, as there's a strong possibility of getting several more logs from the same source.....)

Thanks for any help/advice.

Regards,
Paul.

 

[Paul.J]

Paul.
Your logs will have to be spilt down the middle to relieve the tension that is in the wood.
Best thing to do is measure the dia of the log and cut the log a few inches longer then the diam,and then split it.Seal the ends with your PVA,and store in a cool dark dry place.
What i've started to do now is cut the split logs to the round blanks and also still sealing,and storing.
I have also part turned some blanks,and left for a few weeks,some have split some have been o.k.
Also tried the meths drying which so far as been 100% successful.
All trial and error at the moment with me.
Paul.J.

 

[TEP]

Hi PaulH.

Any log over about 4 - 5 inches even end sealed, will split unless it is dried very VERY slowly. To save all the hassle most do as PaulJ has just said, either wet turn, or cut through the centre pith, seal and dry.

 

[Losos]

Hi Paul,

First, I'm no expert and I expect there will be someone along in a mo' who can offer some advice.

I did read on here only recently that softwoods e.g. Pine can be more difficult to turn than hardwoods, so first I would suggest you try to confirm what type of wood it is.

In the same thread I think it said that sharp tools are even more important on Pine.

It sounds like the wood has recently been felled, and if so it may need to dry properly. Maybe some slight cracking while drying is unavoidable.

Just a few random thoughts. I will be reading any other replies with interest as I have some 2Mt. logs of Ash which are also cracking on the ends & they were sealed with paint.

 

[greybeard]

FWIW I don't immediately throw out rough-turned work that appears to split. Sometimes, for no evident/obvious reason to me, the cracks reduce or even disappear! (I'm also too mean to throw anything that 'might' turn out to be ok - I'll hang on to it a bit longer just in case!)

It's a bit like the general timber drying conundrum, e.g. oak beams that have been perfectly stable in a barn for 250 years are 're-cycled' for whatever purpose and promptly split. All to do with changes in moisture levels. In respect of moisture take-up/reduce capability wood never 'dies'.

Sometimes wood (particularly newish cut that appears to be fine) is stable in store/garage/shed/workshop, and then splits/moves when the masterpiece is installed in a centrally heated house! Happens to us all. Which knowledge doesn't make it any less upsetting when it happens!

Sometimes I lose 10% of my blanks, sometimes I lose 30% or more. Thankfully - at least to date! - anything I've paid for has given zero or minimal losses.
Anything with knots/branches will be more prone to split - cos there's more inner tension in the wood.

Turning 'straight' wood (that's straight as in no knots, no burrs or other intrusions) can often result in a very good finish relatively easily. Which is good if your target market is kitchen treen. And you can get the pieces looking almost identical! (You will not appreciate the power of that until you've tried to produce more than two similar items!).

But - and here's the no pain no gain bit! - the grain and colours around and through knots can be absolutely breathtakingly heartachingly gutwrenchingly eyewateringly beautiful! Not that I'm in any way biased of course.

Cracks near/from/through knots can also be caused by over-enthusiastic sanding - something to do with the physics of heat build-up and transfer/dissemination characteristics I think. If it helps, when you sand only use one thickness of abrasive cloth/paper, and apply pressure through your fingers - no gloves. If it burns your fingers then it's burning the wood too. Rule of thumb is to always reduce the lathe speed for sanding, or even do it with the workpiece stationary.

Final thought - wherever you're storing your logs or blanks to dry/stabilise, make sure they are out of direct sunlight, cos that'll crack an otherwise perfect blank seemingly in minutes! (did you detect the slight edge that signifies that this is very personally confirmed knowledge?!).

Good luck!

 

[PaulH]

Thanks for all the very helpful replies above - I'll try cutting the log through its pith and see what happens.

Regards,
Paul.

 

[geoff_tulip]

i agree with the above the log will split when left in the round - cut the pith from the logs and then cut your bowl blanks - some timbers will split no matter what you try - softwoods dry differently than hardwoods because of their cell structure and are usually easier to dry - since you are local to me you are welcome to come and see how to mill timber into blanks - dry it and turn it - it will save time and alot of frustration in split wood or finished products splitting. get in touch if you wish......otherwise have a good look at the book Turing Green Wood it will help alot...

 

[PaulH]

Geoff,

Thanks for the offer - PM sent.

Paul.