Ash age hardening ?

[cornish wood burner]

most species have some sort of hardening unless they get a fungal infection (not always obvious or visible) which breaks down the lignin making splitting easier.

 

 

i had some ash which had been left outside and the parts that had not succumbed to rot were like stone and bone dry...

 

So it's the lignin drying and hardening over time making it harder to split?

[openspaceman]

I've just been splitting some 6 to 12 inch ash that has been in the back of my shed for a few years. Almost all needs the full 8 tonne of my splitter, then it goes off like a gun. I kept these rounds intact for ease of handling but I'm having a rethink on that.

Is it the sap hardening doing this?

 

Last year my firewood was mostly 30 year felled yew tops and a load of off cuts of the same after they had been sculpted. Gave some of the bigger bits to a mate who had bought a 6 tonne Riko electric splitter. He gave up on them, not because they wouldn't split but for fear of breaking the windows at the front of his hose.

[treequip]

So it's the lignin drying and hardening over time making it harder to split?

 

As timber dries it shrinks as will pretty much anything we can dessicate

 

As the timber dries the moisture loss leads to a tightening of the cell structure

 

Its this that makes the wood tougher

Edited December 28, 2015 by treequip

[Capetown]

Dunnage it is! https://en.wikipedia.org/wiki/Dunnage

[mendiplogs]

I've just been splitting some 6 to 12 inch ash that has been in the back of my shed for a few years. Almost all needs the full 8 tonne of my splitter, then it goes off like a gun. I kept these rounds intact for ease of handling but I'm having a rethink on that.

Is it the sap hardening doing this?

 

Hi CORNISH try beach mate or oak thanks Jon happy new year 👍

[Aunt Maud]

As timber dries it shrinks as will pretty much anything we can dessicate

 

As the timber dries the moisture loss leads to a tightening of the cell structure

 

Its this that makes the wood tougher

 

That's right.

 

It's a result of microfibrillar structure becoming more compact when the moisture bound within the cells dries out.

 

Timber contains two types of water Free Water and Bound Water.

 

Free water is in the cell cavities and is the first that is removed during the drying process and the timber is said to be at Fibre Saturation Point, which is just above air dry .

 

Bound water is chemically bonded within the cell structure and this is removed generally with heat, either within a kiln or heated house, and it's at this point below FSP where timber does its shrinking.

Edited December 29, 2015 by Aunt Maud

[Aunt Maud]

Timber contains two types of water called Free Water and Bound Water.

 

Free water is in the cell cavities and is the first that is removed during the drying process and the timber is said to be at Fibre Saturation Point when its removed, which is just above air dry .

 

Bound water is chemically bonded within the cell structure and this is removed generally with heat, either within a kiln or heated house, and it's at this point below FSP where timber does its shrinking.

 

Although prolonged air drying in good conditions will remove some of the Bound Water.

[cornish wood burner]

The ash in question has severe shrinkage cracks so presumably its lost some of the bound water over the years which has tightened the cell structure. For my own interest I might do a moisture check on a couple of these pieces. I also have some lengths of smaller diameter of the same age under cover so I expect that will be similar. What surprised me was the brittleness of the straight grained pieces. Knots are actually a help as then it seems to split slower and I do not need to retrieve the pieces from across the shed. In future I will try and split the ash before it gets to this stage. It's good to understand what's going on, thanks all.

[Aunt Maud]

You're slowly putting tension into the fibres wood with the splitter. When the fibres suddenly release because the tensile force slowly increases and becomes to great for them to resist then the wood flies around. Pow!

[Stubby]

You're slowly putting tension into the fibres wood with the splitter. When the fibres suddenly release because the tensile force slowly increases and becomes to great for them to resist then the wood flies around. Pow!

 

I would have assumed ( wrongly perhaps ) that it would be compressive forces rather than tensile as the splitter is effectively compressing the wood until the split occurs ............