I recently acquired a Halios Tropik B, a fine watch constructed of aluminum bronze. The watch came with a very nice, but somewhat rugged looking, straight-cut, 22mm leather strap. I wanted to fit a dressier strap that tapered from 22mm at the lug end, to 20mm at the buckle. Finding a suitable strap was quite easy, but finding a buckle was another matter entirely. You see, the world's inventory of bronze buckles is rather small, and mostly comprised of 26-24mm Pre-V style. As more manufacturers adopt bronze or brass for their cases, the variety has increased somewhat, and now it is possible to buy 22mm buckles in a more conventional rounded style with a flat prong. What I wanted was a 20mm bronze or brass buckle, in a classic style, with a slim prong. No luck. There are plenty of polished gold tone buckles out there, but they are generally a poor match for bronze.
After commiserating with some fellow bronzo nuts online, I decided to take their advice and "torch" a stainless steel buckle instead. This process requires heating the buckle over an open flame to darken the metal. I had only seen deeply torched buckles before, where the metal had been heated to the point that it developed purple and blue patterns and dark scorches. It is a great effect, but more than I wanted. I learned that with a bit of care and patience, one could heat the buckle just enough to develop an even golden tone, making it a fairly good match for bronze.
I chose an appropriate donor buckle in stainless steel with a brushed finish to match the case of the Tropik. Please note that this process will not work on a chrome plated buckle.
Because the frame and prong are different sizes, they do not turn at the same rate, and must be heated separately. I removed the prong, and used the spring bar as a grip so I would not scratch the buckle. I thought the heat might damage the bar, but it emerged from the process unscathed.
You will need a steady heat source. Some people have used lighters, but I would suggest something you don't have to hold. A gas stove top is perfect. Keep the buckle at the tips of the flame and take your time. You don't want to torch the buckle so much as toast it. The frame took about 15 minutes to reach the desired color, held over the flame in short intervals, with frequent turning, checking, and comparing against the watch case I was attempting to match.
I would have loved to show you some action shots of the buckle over the open flame, but I have learned that it is impossible for me to do two things at once, particularly when one of those things is on fire!
The prong must be done separately, and it will turn much quicker. As you can see, I learned this the hard way. The blue-purple effect is actually quite cool, but it is not what I was going for. A second donor prong was drafted into service and this time, I checked it every few seconds. It turned in no more than a minute or two. Remember, once the metal has darkened, there is no going back.
The aluminum bronze of the Halios is not terribly easy to match. In the end, my buckle was a touch darker than the target color of the case, but good enough. Particulary since it will be worn on the underside of my wrist and not right next to the head. Bear in mind that bronze and brass are "living" metals. They will darken and tarnish over time as oxidation takes its toll while a stainless steel buckle will not. Eventually, the case and buckle will no longer be an acceptable match, but while I generally like a natural patina on a bronze watch, I plan to keep the Halios in its original shiny state. All in all, I am very happy with the result.