Working with green wood

[Russell]

As noted elsewhere on this fine forum we have recently felled a couple of hazlenut trees and I decided that I would make something with a section from one of the larger trunks.

With the help of a power planer and hand plane the top surface is approaching the desired shape (a bannister rail) and I now need to work out a plan for shaping the bottom half.  Anyways my question is, do I need to wait until the wood has dried out before trying to sand to final shape and to put a finish onto it?

Can I sand green wood - I doubt it!   Any tips?

Thanks


R

[Zoidburg]

Just because it's one shape now does not mean it will be that shape when it dries out.

Think "pretzel" as a possible end result.

You need to wait a long time and store it somewhere dry and with constantish temperature, or it has to be kiln dried.

[redshift]

Oh crikey, Zoidburg is right - you could end up with a very bendy piece of wood.

Green wood shrinks, often substantially, and shrinkage is not even - it depends upon the grain direction, so it will shrink more in certain planes than others.  This is one reason for splits and cracks in the first place - another is the straightening of the fibres, which often applies a torque to the piece as it dries.

One way out of your current position is to make the piece and get it in place, hoping that the fixings will hold it in shape whilst it dries.  This is how green oak beams can be done, as large beams are often too thick to kiln dry anyway.  Another possible way is PEG (polyethylene glycol) - cut and shape the piece and get it into a PEG solution before it dries.  The glycol will substitute itself for the water in the wood.  This might be expensive, but the wet wood shape will be retained with minimal shrinkage. 

Preferred method of air drying would have been to plank the trunks and sticker-stack them with air gaps for about 5-10 years, planing them flat and square after that.  I know, that's a bit like asking for directions and being told "I wouldn't start from here..."   

Simplest and cheapest option might be to simply go for it, and take any twistiness as a feature, not a fault.

[Russell]

Thank you for your replies and concern but I feel I did over state the quality of the piece of work I would like to produce!   

The piece is about 400x70x50 so the opportunity for it to go banana shaped is limited.  It is (may be) replacing a bit of sawn timber so if it ends up rustic then so be it. 

I'll roughly shape the underside and then put it to one side (airing cupboard?) for a few months then finish it.

R

[redshift]

Ah, ok. Airing cupboard is good!  I keep my good quality wood in the house anyway (Limba/korina, Palisander rosewood and some fiddleback sycamore at the moment).  Some of them are air dried, not kiln, and this way they even out to 'household' dryness, and when the finished product is made, they don't usually warp any further.

[mrcharly-YHT]

Seal the ends (beeswax is good, ordinary candle wax will work ok), don't do final shaping and sanding.

[fred the great]

Don't do anything to it at this stage except keep it dry in the house at a reasonably constant temperature. Are you able to check the moisture content? I think kiln dried is about 14% but can't remember the actual figure. When it is down to the required moisture level is the time to finish it and to seal it from any further  moisture absorption.

With this approach there will be no twisting and shaking