Polishing Brass – or where to get P5000 paper

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Polishing Brass – or where to get P5000 paper

Home Forums Beginners questions Polishing Brass – or where to get P5000 paper

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  • #248580
    Robin Graham
    Participant
      @robingraham42208

      Normally when I want a brass summat to look shiny bright, I take it to P2500 then Brasso and it looks OK. But the other day I did that on a piece, then it caught a glancing light which showed a visible scratch pattern. OCD kicked in and I bought a polishing set which comprised a stitched wheel with 'brown compound' for preparation and a floppy wheel with 'blue compound' for finishing. It works OK, but it takes forevever for the 'brown compound' to get the P2500 scratches out, hence my wondering if there's anywhere to get P5000 at a reasonable price – a Google search turned up a source at about £4 a sheet but I'm not as mad as that!

      Or is there a better way of getting a specular finish on brass? I realise that it's pretty pointless as you only have to touch the stuff with a less than forensically clean finger and it's scratched again, but I'm interested.

      Rob.

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      #8228
      Robin Graham
      Participant
        @robingraham42208
        #248589
        Ed Duffner
        Participant
          @edduffner79357

          Hi Robin,

          On mostly plastics I've used a product called micromesh by Alclad. The stuff I had goes up to P12000 and is used to remove scratches from clear plastic, e.g. aircraft canopies). I think I remember seeing a while back, a chemical process to surface metal to a mirror finish, possibly on youtube.

          Ed.

          #248595
          john carruthers
          Participant
            @johncarruthers46255

            Have you tried optical polishing pads as used on telescope mirrors etc? they are disposable and work quite fast.
            Otherwise the various optical 'grits' go down to cerium or tin oxide, or the old fashioned rouge. They can all be elutriated to get a finer finish.

            #248596
            Michael Gilligan
            Participant
              @michaelgilligan61133

              Robin,

              I recommend that you try using [previously Solvol] Autosol as your polish, after the abrasives.

              … It has more 'cut' than Brasso, but is capable of producing a very high polish.

              From your description, it sounds like you are 'polishing-up', rather than 'polishing-out', the micro-scratches.

              MichaelG.

              #248611
              Bob Stevenson
              Participant
                @bobstevenson13909

                At Epping Forest Horology Club we tend to either be 'Autosol Men' or 'T-Cut People'…both have their adherents who prefer one or the other for various reason. Personally, i'm a T-Cut fancier, but not by much!

                Most members of the club who are serious about polishing brass (and there are some who are VERY serious!) stop with the abrasive papers at around 3000 and graduate to 'microfinishing film' which are made both by 3M and also by some Swiss makers notably Graessner. These films are described in microns unlike abrasive paper.

                We mostly aquire our films from the large horological supply houses, Walsh or Cousins…see here for Cousins finishing films……..

                https://www.cousinsuk.com/search?SearchTerm=finishing+film

                A word of caution if you are going to get involved with finishing film,……..it's not as easy as it looks and there are several pitfalls for the unwary. Contamination quickly becomes an issue…it's highly irritating to get a superb finish on a piece and suddenly find that the surface has efects due to microscopic contaminants. For this reason its quite easy to become an obbsessive before you realise it and you are suddenly looking at a forensic white overalls and turning the shower room into a laboratory………You have been warned! Then there is the issue of keeping the films stored in utter cleanliness…….

                Unless you are aiming at the very finest work it might be a plan to polish to 3000 or so using a sheet of plate glass to hold the paper to, and then use Liberon 0000 wire wool (which is super nice and fine to use) and then a CLEAN polishing mop in the lathe with just a touch of T-cut…..

                #248623
                An Other
                Participant
                  @another21905

                  I needed to polish some brass to a fine finish, and found a kit (by accident) in a local car spares shop used for polishing out scratches in car paint. It was two (small) tubes of white polish, apparently one finer than the other, meant to be used in succession. It did a good job, but I think in future I will stick to Solvol Autosol – seems to polish anything to any standard, depending on how long you use it!

                  #248626
                  MW
                  Participant
                    @mw27036

                    I'd use some flour paper and then maybe a little bit of brasso, Incidentally, if you want to get a good finish with aluminium or stainless go for PEEK paste, works really well, slight ammonia smell to it though.

                    Michael W

                    #248628
                    roy entwistle
                    Participant
                      @royentwistle24699

                      Tooth paste ?

                      #248631
                      Ajohnw
                      Participant
                        @ajohnw51620

                        3M and others produce some films for both polishing and lapping that go down to a 1um grit size. There are also some discs of it around that are intended for polishing the ends of fibre optic cables – these will polish HSS and just plain water makes a decent lubricant to prevent clogging.

                        The best place I found to buy a sample pack of 3M's product was Cousins UK, watch and clock bits suppliers. Prices elsewhere were sometime a lot higher or the A4 sheets had been cut up.

                        The discs – RS or ebay.

                        John

                        #248632
                        Michael Gilligan
                        Participant
                          @michaelgilligan61133
                          Posted by roy entwistle on 30/07/2016 11:02:12:

                          Tooth paste ?

                          .

                          … In principle, probably O.K. but you would need to select a suitable product [many have all sorts of questionanble chemicals in them, and the abrasive content varies too].

                          Autosol is consistent in quality, and 'handles' nicely … Given its modest price, I wouldn't bother experimenting.

                          MichaelG.

                          #248655
                          Hopper
                          Participant
                            @hopper

                            Been using Solvol Autosol on aluminium motorbike engine covers and the like for 40 years or more with very pleasing results.  The bit of brass I have used it on showed similar results.

                            Edited By Hopper on 30/07/2016 12:32:42

                            #248658
                            Ian S C
                            Participant
                              @iansc

                              The most abrasive toothpaste I have come across was the stuff suppl;ied free on British Airways in the early 1980s. Used tooth paste to prepare steel samples for microscopic study when I was at school in 1963.

                              Ian S C

                              #248660
                              Watford
                              Participant
                                @watford

                                Good old fashioned newspaper (newsprint) works pretty well. Just a drop of Brasso for lubricant.

                                Mike

                                #248662
                                Speedy Builder5
                                Participant
                                  @speedybuilder5

                                  Very fine wire wool but make sure it doesn't grab your fingers. If you want to err on the side of safety, attach a wad to a wooden stick and use like that. then Autosol etc.
                                  BobH

                                  #248667
                                  Michael Gilligan
                                  Participant
                                    @michaelgilligan61133

                                    Forgive me if I am stating the obvious, but I think it worth mentioning:

                                    Technique is just as important as the choice of abrasives and polishes …

                                    I went on a short course a few years ago, given by Buehler, on preparing metallurgical samples.

                                    http://www.buehler.co.uk

                                    They drummed it into us that each successive fineness of filing/abrasion/polishing should be done at right-angles to the last, and must be continued until all trace of the previous work is removed. … If this is not done, then [as I mentioned earlier] you will end up 'polishing-up the scratches'.

                                    MichaelG.

                                    #248724
                                    Robin Graham
                                    Participant
                                      @robingraham42208

                                      Thanks for all your replies – plenty of leads to follow up. Pro tem, I've ordered some Autosol as it seems to be generally recommended. If it's good enough for horologists (who I know can be – quite rightly IMO – a bit obsessive about finish) it'll probably be OK for what I want to achieve but I'll follow up the other suggestions as well.

                                      MichaelG – the advice given to you by Buehler reminds me of what I was told in my first job after leaving school – I had to prepare metallurgical samples inter alia. Like every lad before and after me I expect, I thought that a tiny scratch in the wrong direction would yield to the next grade and save me some tedious work. But it never did of course.

                                      Rob

                                       

                                       

                                      Edited By Robin Graham on 30/07/2016 22:17:58

                                      #248728
                                      Michael Gilligan
                                      Participant
                                        @michaelgilligan61133
                                        Posted by Robin Graham on 30/07/2016 22:16:31:

                                        MichaelG – the advice given to you by Buehler reminds me of what I was told in my first job after leaving school –

                                        .

                                        blush So we can safely assume that 'Granny knows how to suck eggs'

                                        MichaelG.

                                        #248732
                                        Robin Graham
                                        Participant
                                          @robingraham42208
                                          Posted by Michael Gilligan on 30/07/2016 22:46:42:

                                          Posted by Robin Graham on 30/07/2016 22:16:31:

                                          MichaelG – the advice given to you by Buehler reminds me of what I was told in my first job after leaving school –

                                          .

                                          blush So we can safely assume that 'Granny knows how to suck eggs'

                                          MichaelG.

                                          Sorry if that came over wrong – this Granny certainly doesn't know how to suck eggs! T'was a long time ago and it sparked a memory,

                                          #248734
                                          Michael Gilligan
                                          Participant
                                            @michaelgilligan61133
                                            Posted by Robin Graham on 30/07/2016 23:21:37:

                                            Sorry if that came over wrong – this Granny certainly doesn't know how to suck eggs! T'was a long time ago and it sparked a memory,

                                            .

                                            Not wrong at all, Rob

                                            MichaelG.

                                            #248749
                                            Sandgrounder
                                            Participant
                                              @sandgrounder
                                              Posted by Michael Gilligan on 30/07/2016 14:00:21:

                                              Forgive me if I am stating the obvious, but I think it worth mentioning:

                                              Technique is just as important as the choice of abrasives and polishes …

                                              I went on a short course a few years ago, given by Buehler, on preparing metallurgical samples.

                                              http://www.buehler.co.uk

                                              They drummed it into us that each successive fineness of filing/abrasion/polishing should be done at right-angles to the last, and must be continued until all trace of the previous work is removed. … If this is not done, then [as I mentioned earlier] you will end up 'polishing-up the scratches'.

                                              MichaelG.

                                              That's taken me back to the early 60's, something I'd forgotten about, Selvyt cloths and diamond paste polishing of steel samples for examination under the microscope, not one of my favourite jobs at work.

                                              John

                                              #248758
                                              Steve Withnell
                                              Participant
                                                @stevewithnell34426
                                                Posted by Michael Gilligan on 30/07/2016 14:00:21:

                                                Snipped…

                                                They drummed it into us that each successive fineness of filing/abrasion/polishing should be done at right-angles to the last, and must be continued until all trace of the previous work is removed. … If this is not done, then [as I mentioned earlier] you will end up 'polishing-up the scratches'.

                                                MichaelG.

                                                Thanks Michael, that's a really good learning point for me.

                                                Steve

                                                #248828
                                                Robin Graham
                                                Participant
                                                  @robingraham42208

                                                  Well, the Autosol arrived today – ordered off Amazon about 5pm Saturday, and with me by Sunday noon! How do they do that? Anyhow, it's pretty good stuff – thanks for the recommendations. The scratches on my work are now shiny scratches! I think Bob Stevenson's caveats apply to me – trying to get a mirror finish in a dusty home workshop is unlikely to be successful because of cross contamination. It probably doesn't matter, the guy I'm doing this for is hardly likely take a microscope to the work and cancel the cheque because of a 5 micron scratch – but I've got a bee in my bonnet now.

                                                  Rob

                                                  #248850
                                                  Neil Lickfold
                                                  Participant
                                                    @neillickfold44316

                                                    Some really good info in the above posts. What can cause scratching and effect your finish is the polishing cloth you are using. Home paper towels are terrible at scratching. Lens wipes are very good and so is Hydraulic lint free wipes. Cotton cheese cloth that car polishers use is very good as well. Very soft balsa wood makes for a great lap and very fine polishing compound holder as well. A little bit of very fine diamond in balsa wood lasts a long time and works well. The hardest part of it all is to keep the contaminants away from one process to the other. You just can not ever be too clean when it comes to polishing. Cleaning is essential between grades . The finer the finish the more it is involved, especially at keeping the contour to form is definitely easier said than done. There are lots of little tricks to keep the form correct and each situation will use a combination of ways to achieve this. Like polishing in 2 directions to ensure you have the scratches from the previous grit fully removed before going to the next level, etc.

                                                    Neil

                                                    #248862
                                                    Jon Gibbs
                                                    Participant
                                                      @jongibbs59756

                                                      Hi Neil,

                                                      I'm not sure whether you know this site or not but there's a lot of good info and products here… **LINK**

                                                      I've no association with them, just a satisfied customer.

                                                      I use tripoli on wooden items but it's original purpose is as a first stage abrasive for brass polishing I believe.

                                                      HTH

                                                      Jon

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