Thanks for the input everyone
Thanks Ian for your comprehensive posts. It is clear you have a great deal of knowledge on the subject. I am now thinking of a 6 stage column, and yes treated timber would be easier and cheaper, but that is not what I want. So I will have a foundation, probably 4 bar trench mesh, 8-9 metres long. A square column base easily formed by myself with reliefs made on a scroll saw. This would be made do that black ply for form work. This would be 1.2 metres high. Then there might be the relief form from American 200 mm high and a custom orb column 1-1.2m high then another American bought ($50 for postage) form on top. Then I the treated pine or concrete frame for the top. It will all be tied together. These columns will weigh about 160 kg.
I appreciate your comment about the look of a thin column. It is something for me to consider but if it is only 1 or 1.2 m over a square pillar it might be okay. I must draw it up but I am only getting ideas together. My original post was really hoping to find retailers who sell for work but I am over that now. I think the ideas are coming together and I thank you all at WWF.
ps. Where in Sydney are you. I grew up in Hornsby (Mt Colah)
1 Attachment(s)
Keeping the starter bar in the middle
Attachment 289784I have 3 bar 11 mm trench mesh in my test project. I will use 12 mm deformed bar going up inside a 150 mm PVC tube. The starter bar will be tied into the trenchmesh. I would appreciate some ideas on how to keep the 12 mm bar in the centre of the PVC. The PVC tube will be about 1.9 m high.
the foundation formwork allows for footings 0.32 m wide and about 0.2m deep. Under the columns footings are about .3 x .3 m x .3m.