John Carmichael wrote: > >I now polish the engraved brass compass rosettes that I often inlay into my >dials. I have been using an electric palm sander with 1500 grit sandpaper >wetted with water and a tiny bit of detergent. I want the surface to be as >shiny as possible. > >This procedure works fairly well but the gloss isn't quite as bright as it >could be. Even using this fine grit, I can still see very small scratch >lines from the abrasive. Do you think emery sandpaper would give a higher >gloss than 1500 grit? Also, do you prefer electric or hand sanding?
There is a time when you have to leave abrasive papers and move on to much finer 'polishing soaps' and a revolving polishing 'mop' made up of cotton discs made up into a thick sandwich. Polishing 'soaps' are bars of hard grease/wax containing abrasive powder. They are applied to the spinning mop and the heat/friction transfers them. They need frequent application. The sequence I use is:- Try not to put any scratches into the metal in the first place! :-) Successive grades of 'wet & dry' paper on a cork block by hand as used for auto bodyfinishing e.g. 400grit - 600 grit - 1000 grit - 1200 grit for as fine as they go with plenty of running water as lubricant. Each grade should be applied at right angles to the previous one and continued until all previous scratches are removed before starting the next grade. At one time this was followed by 'Tripoli' polishing soap on a cloth mop again followed by Jewllers' Rouge soap and then liquid metal/brass polish. Tripoli/rouge 'soaps' continue in use but have been supplanted by modern soaps which do not leave a greasy deposit. A jewllers/dental supply company will advise. DON'T try to polish scratched metal on a mop as all you will get are shiny scratches! If it takes a long time to get a satisfactory gloss then your preparation stages have been insufficient and you will polish away detail and round off clean edges. Dwelling overlong on the mop can produce an 'orange peel' surface especially if you apply high pressure with the coarser grades. For a very fine finish a 'swansdown' (very soft cotton) mop is advisable. For flat surfaces a Selvyt cloth and fine alumina powder in distilled water is an alternative final stage or, if your pocket will stand it, 6 micron and then 1 micron diamond paste. The good thing about diamond paste is that it never wears out - the Selvyt cloth just disintegrates around it eventually. No doubt others have equally successful procedures. Tony M. P.S. Have you considered gold plating?....it may be cheaper than you think and the platers will do the fine polishing for you! ;-)
