Well I’ve just unscrewed mine to see what I did 20 or so years ago.
Looks like it cut and rolled the mesh around a bit of bar. Inserted it into the banjo bolt and fitted a turned top cap. I would think I fluxed the bolt and cap and then used a blowlamp to heat it and solder. (might have tinned them first) The blobs down the joint look more like they were done as a second operation with a small electric iron and cored solder. good job it is out of sight.
I suppose if I were doing it now it could be rolled with a bit of an overlap, some JBWeld spread into the bolt and cap then just push it all together.