Right from the start of mixing bottle bottoms with copper-foil designs, I’ve used a 3mm UV-bonded clear circle blank as a backing piece for the bottle ends, as I’ve always felt it adds strength though a fully soldered joint and overall appearance improvement. Occasionally though, despite very careful bonding, and neat soldering, a few drops of water have sneaked through into the enclosed bottle bottom cavity when washing away the patina. I’ve managed to dry them out using natural sunlight, open fires and even industrial desiccant, but it’s not without some water streaks left inside to drive me mad! No-one notices them, but I do. I still think it’s by far the best way to make them though, but out of curiosity for the alternative, I thought I would try one without backing as an experiment.
I begun by foiling the cut edge of the bottle bottom, which , with care, wasn’t as untidy as I thought it could be. I lifted the bottle end up towards the front surface using some 3mm glass, ensuring the front solder was as substantial and visually neat as the backed centres method. This ensures a good looking front face, which is the most important thing in a window hung design. This leaves a step between the two rear foiled surfaces, for solder to form a sloped join. The result is ok, but does need the sort of working that puts a lot of heat in during smoothing. It’s pretty strong, but what I don’t like about this method is that it leaves a tinned edge on the upper edge of the round, which is a little bit vulnerable to careless cleaning. From the front, you wouldn’t really tell the difference between the two methods, and it looks good hanging on a window surface. I guess time wise, it probably saves a good half-hour or so from by cutting out the need for a 3mm circle and the UV bonding, but I still prefer the end results from the backed method I’ve been developing over the last year or two. It’s been useful to try it out, and I would use this method again on a design that is very one-sided in viewing orientation.