final polish

Discussion in 'General Engine Discussion' started by rleete, Jan 10, 2009.

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  1. Jan 10, 2009 #1

    rleete

    rleete

    rleete

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    Well, I'm nearing completion on my first engine. So, I've been working hard at getting it looking nice. Sanding with ever finer grits (down to 1000), and then off to the buffing wheel. I start with tripoli compound on a spiral sewn wheel, and move to white polishing compound (sticks, not sure what it is) on a loose sewn wheel. All well and good. Shines up fairly nice.

    But, when I get to that last bit, I can't seem to get the streaks out. It's the last minute bit, when the light hits it just right. More or less pressure on the wheel, more or less compound applied, nothing seems to get rid of it. If I turn the part 90 degrees to the last buff, the streaks seem to go in that direction. So, it is micro scratches? What do I use to eliminate them?

    Parts are 360 brass and 6061 aluminum. Both exhibit the same hazing.

    Hints?
     
  2. Jan 10, 2009 #2

    Divided He ad

    Divided He ad

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    Aww... you gets around!! ;D (private ish joke!)

    Still... personally I think solvent type clean and then reassess... possible too much 'soap' (polish) on the mop.. or the wrong type?
    Should be non greasy and non cutting type of polish last. also very little on the mop and probable use of 'Vienna lime' on the polishing mop to remove greasy residues.


    Good luck Roger.



    Ralph.
     
  3. Jan 10, 2009 #3

    shred

    shred

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    You can also try some hand-work with Mothers mag-wheel polish; found in auto parts stores. I've seen some really impressive Al bits done with that.
     
  4. Jan 10, 2009 #4

    kvom

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  5. Jan 10, 2009 #5

    Richard Carlstedt

    Richard Carlstedt

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    The white compound is too harse for the soft metals for a final rub.
    You can try a automobile car polish which has a mild abrasive in it.
    You can try a automobile rubbing compound , which is mildly abrasive.

    For the best polish, I use "Semi-chrome'
    This is a polish made in Germany and is the absolute best Aluminum polish I have ever seen. a small dab goes a long way.
    They have another name for the same product, except it comes in a tube, not a can but i don' t recall the name
    Try this to see the product
    http://www1.mscdirect.com/CGI/NNSRIT?PMPXNO=12143135&PMT4NO=56280015

    Rich
     
  6. Jan 10, 2009 #6

    ghart3

    ghart3

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    Sounds like your doing things right, sanding to get a even flat surface first. Not sure what your white compound is, good chance it is not meant for softer metals. I have a white compound that is meant for stainless steel. I have been using a compound from a jewelry supply place called Fabulustor. My quick and dirty method is draw file and or sand with a hard backing board. Maybe use a Scotch Brite wheel. Buff with Fabulustor only and maybe hand polish.

    Like Shred suggests using a hand-work polish like "Mothers" work good as final polish. My favorite is Semi-Chrome brand. These hand type of polish seem to give some protection to the metal for awhile if the putting a clear coat on.

    Ralph, question. What is 'Vienna lime' ? Haven't heard of it and would like to try it.
    Gary
     
  7. Jan 10, 2009 #7

    rleete

    rleete

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    Thanks for all the tips. Here's a follow up:

    Being the geek I am, I decided to have a look under magnification, and then run it through the wheel and look again. I used the brake cleaner trick (I use it for degreasing everything) to get the parts squeaky clean before the test. Problem #1 is that it wasn't as smooth as I thought. The part still had small marks in it that should have been taken out before hitting the wheel. Turns out the sandpaper I used was 800, not 1000, and it looks like I need a lighter touch, too. Or, more time on the cutting compound before moving on to the finer one. Impatience on my part.

    Problem #2 is too much compound. New wheels; laid it on too thick. Hard to get it right on those loose wheels, too. Tripoli from the first wheel was getting into those small pits, and the lighter polish was dragging it out and making things worse. Do you guys clean the part in between polishing steps? Can I wash a wheel to degrease and clean it?

    Problem #3 is that the white (listed for soft metals, bought at HF) appears to have too much cutting for a final polish, I think. It might be the contamination with the tripoli as well. They are scratches, and show as a haze. Magnification reveals them for what they are.

    Testing with a hand polish (I use Tarnite) got the worst of the haze off, but it still needs a little work. I know some of the car guys swear by Mother's products. I may have to go get some to try.

    So far I've been using old t-shirts to do the hand work. Is there a better alternative?
     
  8. Jan 10, 2009 #8

    Marinesteam

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    You may be contaminating the final polish with residue from previous steps. Cleaning the part between compounds is an absolute must. Any residue from previous steps will continue to cut making scratches that are the same as the ones that you are trying to remove with the finer compound. Some use brake cleaner. I've been using denatured alcohol because that's what I had handy.

    I have started using separate buffs for each grit because it saves dressing the buff (which seems to wear them down quickly) each time you change compound. Just spin the next wheel on the buffer and your ready to go. Also, you don't mention what type of buff you are using. A flannel buff wheel works wonders on the final polish grit.

    I get all my polishing supplies from reliable sources, HF is great for lots of things but personally I wouldn't trust their quality for polish compound. But you have the stuff from them so don't go changing until you have exhausted the other solutions. My favorite supplier (the usual disclaimer applies) is http://www.caswellplating.com/. They host a good finishing forum too. On their site is a downloadable pamphlet http://www.caswellplating.com/buffs/buffman.htm that is a good resource of polishing tips.

    Happy polishing

    Ken
     
  9. Jan 10, 2009 #9

    Kermit

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    I found plain (elcheapo) cotton balls to be excellent hand held polishers and with its help I have polished many brass uniform buttons and emblems to a pure mirrored finished.

    Ancient graduate of NMMI,
    Kermit
     
  10. Jan 10, 2009 #10
    One other thing to try, is make sure you are rotating the piece relevant to the wheel, do not just rotate in one direction all the time as you polish it with the wheel. Make sure you are rotating it and polishing it in all different directions, this then eliminates the drag lines from forming on the material ALL the same way.
    To clean any mop from a build up of the compounds, get a heavy hacksaw blade and run the teeth over the mop, this will tear away all the build up and get it down to new cloth. Make sure you are wearing a heavy welders gloves when you are doing this with the hacksaw blade.
    For the final polish, an empty/new flannel mop without ANY compound on it, works wonders on any material.
     
  11. Jan 10, 2009 #11

    Divided He ad

    Divided He ad

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    I'm not 100% on that answer Gary, it is just what I was told to use and it can with my polishing kit... The instructions in there say to use it too.

    Here is a link, dragged off E-blag and put here. No idea if it's cheap or whatever but it shows the stuff I'm talking about. ;D

    http://cgi.ebay.co.uk/Imops-4-x-1-G...14&_trkparms=72:1301|66:2|65:12|39:1|240:1318


    Hope that helps?

    The Caswell site and information is fantastic. Shown to many of us before by Bog's. It does a good job of explaining technique and safety :)



    Ralph.
     
  12. Jan 10, 2009 #12

    rleete

    rleete

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    More testing. I turned/faced some blanks of brass & aluminum and tried polishing them. The white stuff has certainly got too much cutting for a final on brass. It hazes no matter what I do. I get really close to the perfect finish, and it still leaves a haze. Turning the part relative to the wheel just makes the haze go in that direction. It does, however, seem to work well on the aluminum. Maybe it helps cut through the oxidation layer just enough?

    For brass, using just the tripoli and than a hand buff came out much better. Found an old flannel shirt to do the hand work, and that was a vast improvement (thanks, greenie & Marinesteam!) over the t-shirt material. I'll have to order a flannel buff - not available locally.

    Automotive paint polish was tried, but it, too, cuts too much for final. It might help to get a different grade, but for now I think that I'll stick to having to hand work the parts.

    Thanks for the help and links.
     
  13. Jan 10, 2009 #13

    ghart3

    ghart3

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    Thanks for info Ralph. Checking out Caswell's site and your link. Guess Vienna Lime is caulk. "A super fine calcium carbonate" according to your link.

    A watch maker friend told me that he had read from an old book that "French Caulk" from the cliffs of Dover was a very good polish for brass.
    Gary
     
  14. Jan 10, 2009 #14

    Divided He ad

    Divided He ad

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    French caulk!!! From our British cliffs!!!! Does HM's customs know the blighters are nicking it??? :big:

    It certainly is fine... softer than any talc I've ever felt.


    I cheat a little .... I put some on the final buffing mop... No soap at all and use it for the final buff..... it seems to work on most of my bits!

    Suppose I could have said that earlier too?... Well I forgot.... I'm like that occasionally! Specially when I'm responding at silly 2-4am times! ::) :big:

    Might help someone?


    Good luck ;D



    Ralph.
     
  15. Jan 11, 2009 #15

    Kermit

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    if you are experimenting plain - old toothpaste might be worth a try.

    I have heard stories of this substance being an excellent polish.


     
  16. Jan 11, 2009 #16

    T70MkIII

    T70MkIII

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    Good point - a friend of mine used to swear by toothpaste for polishing the scratches out of his S1 Land Rover windscreen!

     
  17. Jan 11, 2009 #17

    raym 11

    raym 11

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    Bob Brownell wrote a book "Gunsmith Kinks". It is Worth the price for all the machining tips especially the 40 page section on metal polishing.

    I got mine from the Brownells catalog here in USA.

    I hate polishing and therefore my projects are lacking in that area. This info did help make 'the medicine go down'.

    Ray M
     
  18. Jan 12, 2009 #18

    Bernd

    Bernd

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    Ray,

    I have all 3 books. Great aren't they. There's lot's of info in them. I'd say at least a good percentage could be used in model engineering.

    Bernd
     
  19. Jan 12, 2009 #19

    Kludge

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    The white stuff on a spiral sewn wheel will probably be good for the first cut with the tripoli on a loose flannel or cotton wheel for the polish. There is yet another one (brown in the Caswell kit I have) that goes in between that polishes out the haze from the white compound and is used for the first polish (cut with heavier pressure, color with lighter pressure) before the tripoli. Tripoli has no real cutting capability so can't remove scratches left by previous stages.

    As was previously stated, separate wheels for different compounds (I keep them together using the magic expedient of rubber bands and/or tape) and clean the previous compound off before going to the next step.

    Caswell's book on buffing is a true gem. I bought all my buffing & polishing wheels & compounds from them (and will be buying a few more wheels later for things like rust removal and buffing/polishing plastics), and a dead tree version came with it. The best page is the last page with the table of what wheel and compound to use with what material. That one I printed out oversized from the digital version and taped up in the shop.

    I'm not an expert by any means, and you do NOT under any circumstances want to see the disasters I created when I started buffing & polishing. (I'm still kind of there with grinding but I'm getting better. Kind of.) All it takes is some experimenting and the folks here (well, except that idiot in Hawaii) to make it all good. :)

    Best regards,

    Kludge
     

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