Steam bending oak. ??

[Jacob]

....
It is perfectly possible to heat water vapour above 100C without pressurisation as long as the walls of the heated container are above 100C. .....

Or the spout, say, on a metal kettle. Impossible not to heat it up if the heat is there.
I'm only surprised that some people find this confusing.
Mind you latent heat is more of a head scratcher - but not that difficult - only O level physics.

 

[Noel]

Hi Teckel, good example shown in "Hands" he soaks his timber and then steams it.
http://www.youtube.com/watch?v=XthOkO-wsK4

Though you probably watched this one already

I did Tom. That's why I asked the question. He had it down in the water but I've seen it before done with the steam.

:? He leaves it to soak in the loch (don't know if he said how long) and then steams it I thought? The idea being the water in the timber heats up and the steam get deeper into the fibres. No?

Tom, surely the brothers didn't move to Scotland for that episode...........

 

[Jacob]

My guess is that keeping it under water would keep green wood green and help with bending, but wetting dry wood would not help and just slow down the heating process. So 6 of one and half a dozen.
All gone quite on the physics front! I guess they are trying to catch up. Water is interesting stuff.

 

[Jacob]

Ammonia bending - could be related to the high latent heat of vapourisation of ammonia (1369 kJ/kg)?
Not as high as that magical material - water 2260. Compared to e.g. 855 and 293 for alcohol and turpentine.
And presumably the reason for using ammonia as refrigerant. Why not water as a refrigerant?
Come on physics group! Explain it to us, don't be shy, you've all gone very quiet!

 

[Tom K]

Hi Noel,
Lough Ree (Irish: Loch Rí or Loch Ríbh)
I thought it was only my Dad that extracted the urine out of my spelling and pronounciation of Irish names and places.

 

[Noel]

Hi Noel,
Lough Ree (Irish: Loch Rí or Loch Ríbh)
I thought it was only my Dad that extracted the urine out of my spelling and pronounciation of Irish names and places.

I thought everybody did? <grin>

 

[Jake]

Ammonia bending - could be related to the high latent heat of vapourisation of ammonia (1369 kJ/kg)?

I think the ammonia stuff really screws with the lignin in a seemingly reversible chemisty way, rather all this physics stuff. That's the stuff they sell shrink-wrapped for bending to taste, I think.

 

[custard]

All I wanted to know was "does it bend better with steam or actually putting it down in boiling water.."
I didn't want any science behind it..
Jesus this is gone off on an tangent....close the thread I'm sick to the diddies of it....

Steam's best,

1. More convenient for larger workpieces
2. On balance it's probably safer
3. You're more likely to be working at the correct temperature

BUT...far more important than steam or water is wet/air dried wood versus kiln dried. If it's kiln dried I'll only bend via lamination, bending kiln dried wood is just a waste of time.

 

[Teckel]

All I wanted to know was "does it bend better with steam or actually putting it down in boiling water.."
I didn't want any science behind it..
Jesus this is gone off on an tangent....close the thread I'm sick to the diddies of it....

Steam's best,

1. More convenient for larger workpieces
2. On balance it's probably safer
3. You're more likely to be working at the correct temperature

BUT...far more important than steam or water is wet/air dried wood versus kiln dried. If it's kiln dried I'll only bend via lamination, bending kiln dried wood is just a waste of time.

Thank you custard for clearing that up =D> =D>