I decided (well, to be truthful, SWMBO decided) that I needed to fix the gates which divided our front and back yards. They were about 80 years old, and I had rebuilt them soon after we moved in 40 years ago. About a decade ago I installed tensioning wires on a turnbuckle to counteract the sagging, but wear and tear and lack of maintenance painting had resulted in the main joints rotting, and so I decided not to fix them again, but to replace them.
I have been progressively getting all of the iron railings around the house stripped, dipped in molten zinc, and powder coat painted. For some reason the molten zinc dip is termed “galvanizing” here.
So the new gates would be made with steel SHS (square hollow section) frames, and aluminium slats. I would happily have just copied the old wooden frame design, but SWMBO, who is an architect, decided that would not be “right” in steel, and that the steel frame would have to be the same shape as the surrounding brickwork, which is a sort of Tudor arch. Why we have Tudor arches in Oz is a mystery. Except that back in the 20th century, there was a “British to the boot straps” cultural cringe, and lots of the aspirational class houses tried to look as British as possible. Paradoxically, although I am a confirmed republican, I quite like the “mock Tudor” design. And the house remains cool even in stinking hot weather…. but I diverge.
There has been some ground movement over the years, with the result that the arch is no longer symmetrical, so each gate is different. So I used thin MDF to trace the arch shape for each gate.
With the MDF pattern, I attempted to roll the arch shape in the 50×50 SHS (2″ x 2″), but that was a failure. The SHS did eventually eventually develop a curve, but at the cost of so much lateral distortion, bulging at the sides, that it looked terrible.
So I used a technique that I had used years ago when I made classical guitars, that is to make multiple cuts in the material leaving a thin intact edge, and then making the bends. Each gate required 13 cuts.
The curve is not absolutely smooth, but it satisfied SWMBO. Lucky that her eyesight is not so sharp these days.
The steel was hot zinc dipped, then after some finishing with a file, the steel and aluminium parts were powder coated.
The whole process took about 2 weeks.
Now back to the cannon.