There are various options in the protection of the bars, and it is up to the client to determine the system to be applied in each case. The most usual, however, with this type of structure is painting with epoxy resin or polyester, applied electrostatically in powder form and polymerised in a kiln with a solid layer of no less than 60 microns. This treatment is preceded by surface preparation, which involves, as a minimum, degreasing and phosphating in the case of there being no traces of rust and mechanical brush cleaning or even, if there is rust, scouring. Scouring can be carried out even if there is no rust, in order to increase the adherence of the layer of paint when spatial conditions so indicate.
When greater protection is required, electro galvanizing beforehand is possible, offering a higher guarantee. When the structure is going to be put in a particularly oxidizing atmosphere, it is possible to carry out a process which guarantees absolute water tightness of the bars’ interior without causing any appreciable additional flexibility in the unit.
As for the spheres, usually, procedures similar to that of polymerisation are followed. With large diameters, due to their increased thickness, these treatments are sometimes problematic. When this happens, a scouring preparation is used and one undercoat and two finishing coats of epoxy or chlorine rubberised paint are applied.
In any case, the superficial treatment of the structure is not intrinsic in the ADH system and must be arranged in each case with the client.