Brass, Sweated and Struck: Notes on Surface
Why we finish brass the slow way, and what the eye reads in it.
Modern finishing aims for the mirror. Ours aims for the record. A mirror finish erases the hand that made it; a struck finish keeps the evidence. When you run a finger across one of our ring sets you can feel where the lathe passed, where the burnisher turned, and where the maker paused to read the work before going on.
We sweat-solder joints the old way, with spelter and a blowpipe, then file the seam until the two metals read as one. There is no shortcut that survives a loupe. An apprentice spends their first year almost entirely on files, and the senior makers still sharpen and set their own.
Colour is the last decision. Raw brass is too yellow under electric light, so we tone it with a wash of liver of sulphur and stop the reaction in cold water at the exact second the metal reads as old gold rather than brown. The window is about four seconds. Two makers have done it for the whole workshop for eleven years.
None of this appears in a photograph, which is partly why we keep the visit room. Surface is the part of an instrument you have to stand in front of.