How infuriating - I just posted a lengthy response to Sue and it just vanished into thin air.
Try again.
Sue,
I inherited a large amount of Acacia/Robinia/Black Locust (Robinia Pseudoacacia) from my local council who felled two trees, I got about five tons out of it, and using my bandsaw cut most of it into four inch blanks.
Firstly is what you have a young tree or an old tree? Acacia grows fast for the first thirty years of its life and then slows tremendously. The young wood will probably move significantly although I have no experience of young wood. The quicker it grows and bends in life the quicker it will do likewise once felled rings true. If it is an older tree then the wood is much more stable. The bark, and I note you mention a potential natural edge form, can, on older trees be very soft, and bulky and has a tendency to fly off in large lumps if old and wet, be warned.
If its old you might have large lumps, and you mention a large form in your post so I suspect it might be an old tree. So large lumps will need reducing and you must cut the tree about 3/4 of an inch eith side of the pith, minimum. This will leave you two half logs and the 1 and a 1/2 inch pith section. Cut that out so in theory you have a 1 and a halg square blank with the pith in it and put that on the fire. Acacia is exceptionally good for wood burners as it has a higher calorific value than oak! You will now have two small width quarter sawn sections either side of the pith. These will not move at all, they are very stable. You will get 1% compression across the grain and about 3% along the grain and as it will all be even, it will hardly move at all. The half loge will need the top of the semi circle removing and the sides. You will get around 6-12% shrinkage around the perimeter and if you can interupt this by chopping the top and sides off then you will stop the tendency for the blank to cup and split along its length. If you want to turn it as a ntural edge bowl with the top of the log intact do it sooner rather than later.
Paint the ends if you wish but if you are keeping the wood stored in an area where the tempreature differential between day and night, and importantly the speed with which the tempreature changes is slow, then the wood, providing that it has been cut properly will not split.
The wood turned green is fantastic, the smell is not enjoyed by all though. I think it smells of a freshly cut nettle bed on a wet morning, others hate it, but if you can turn Zebrano then, aromatically, this is a breeze!
It sands and finishes superbly, try wet and dry, the water content in the wood gives a really smooth finish and the shimmer that you can get when sanding down to 1500 is beautiful. On drier pieces I have used wet and dry lubricated with a fine coat of blo which gives an amazing smooth surface.
I am not a great fan of microwaves other than a coffee reheat and would advise against the use of them for any wood! Others think otherwise, but I dry wood for a hobby and a living and the slower the wood is dried the better. You can drive off the water content of wood by heating but stabilising the stresses within is a different matter that takes time. I do not think that you will derive any benefit from putting Acacia in a microwave unless it is a cup holder with a cup of Douwe Egberts in it but cue the responses on this one. It is a strong wood and moves little.
I'll try and dig out a picture of a 14 inch natural edge vase that I turned from a piece of very fresh wood and you can see the differential shrinkage on the bark/sapwood and the heartwood and the way that despite being fresh wood the vase has kept its shape.
I've dried loads successfully and turned it, probably less successfully, but it was all good fun!
