Having tried on the metal sheeting and checked that the overlap would be sufficient, the sheets were bolted to the wooden arches and the top using self tapping 30 mm roofing bolts with integral metal washers and underlying rubber seals. These bolts did an excellent job in fixing the metal sheets to the wood along the seams and below to the steel belt that braced the ring on which the dome rested.
…caulking the edges
As the plating progressed silicone was injected in between adjacent overlaps to provide a seal before the bolts were tightened. This was eventually further supplemented from the inside where possible and revised and trimmed prior to the final painting.
A certain amount of bowing of the sheets between bolts was considered acceptable and a ‘gentle’ tapping down with a wooden mallet often improved the closure between the two leaves of sheeting. It is advisable though not to be overzealous in attempting to produce a perfect molding of the sheets at their area of contact because, as I discovered, this may result in a rather ugly kink that is difficult to put right. Some of the sectors had to be taken off and trimmed to optimize the contour but in the end the result was satisfactory.
… getting dark inside already !
…looking good, shaping up nicely 🙂