We're not talking about dubious 1970s fashion items here, but about the features of no particular value that railway engineers put on the tops of water tanks, both tender and locomotive. Problems arise at the corners. For a sharp corner, is is usually not too difficult to bevel the edges of the flares to obtain a neat join. Much more difficult is the case of round corners, where the flare has somehow to be wrapped around the corner.
It is sometimes recommended that the flare be made integral with the sides of the tank, and subsequently bent over to the correct angle. Before doing so, at the corner, a series of saw cuts is made vertically through that part of the sheet material that will form the flare, creating a set of "fingers". The corner is made by curving the sheet around a rod of suitable diameter, the flares are bent in the straight portions, and then the fingers are splayed out in a sort of conical array. Then one fills the gaps between the fingers with solder, and files it all up to create a smooth conical surface.
I've done that in the past, but never been entirely happy with the result. Somehow the result, instead of being a smooth cone, is faceted. I think it is the difference between the relatively hard nickel silver (or whatever) and the soft solder, which results in the latter being preferentially removed. And while the outside surface of the flared corner is not too bad, in that at least it can be filed with conventional tools, the inside surface is much more difficult to work on. And of course, at the usual viewing angle from above, it is the inside surface that is visible.
So I decided to try something else. The flare is made separate from the tank sides, cut in the flat in such a way that it can be curved at the right point around a suitable conical surface in order to form the corner. Once done, it is simply a matter of soldering the flare in place on the top of the tank.
Download a
data sheet here that shows how to work out the size and shape of the flat
For flared tanks like the one above, I make the flare in two parts, each comprising one side and half the end. There is thus a join in the centre of the end, but in many cases there is a lamp bracket or something similar there that can be used to disguise the join. If not, it is necessary to make the best butt join that I can. But that is still easier than trying to make the whole thing in one piece, because getting the two corners in exactly the right place is next to impossible.