Prepping etched brass....

mtntrainman Sep 9, 2018

  1. mtntrainman

    mtntrainman TrainBoard Supporter

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    I bought some etched brass 3 rail fence.

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    Are there any suggestions for prepping them prior to painting ? I dont want the paint to chip or rub off. I plan to paint them white...from a rattlecan. Any and all suggestions appreciated. TIA
     
  2. RBrodzinsky

    RBrodzinsky Staff Member TrainBoard Supporter

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    I just do two coats, a grey primer and then whatever the color will be. I tried sanding, once, with fine grit, but just ended up bending the brass.
     
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  3. Eagle2

    Eagle2 Staff Member TrainBoard Supporter

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    As long as they're not dirty, nothing special should be needed. However you plan to paint them, I would suggest some form of solvent-based paint for the first coat as it will grip better.
     
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  4. Maletrain

    Maletrain TrainBoard Member

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    I have not personally done it, but I have read that a quick soak in white vinegar will slightly etch the surface and let paint adhere better to raw brass surfaces. Anybody else know whether that helps or has "unintended consequences?"
     
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  5. Inkaneer

    Inkaneer TrainBoard Member

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    I have read that somewhere myself but have never done it either.
     
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  6. JoeTodd

    JoeTodd TrainBoard Member

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    I would bend the fence to the desired shape first, then clean the parts before primer, then paint.
     
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  7. MK

    MK TrainBoard Member

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    Since you are going to paint it white I would get white primer instead of the gray so you don't have to use that much paint to hide the under coat. On the other hand, if you use gray primer you'll know where you missed a spot or two. :)
     
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  8. John Moore

    John Moore TrainBoard Supporter

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    I have done two things trying to prep brass. The first one was using a chemical blackener that left the brass dark with a rough feel and the other has been to soak it in straight a straight vinegar solution for overnight. Both seemed to work for me in both cleaning the brass and leaving a slightly rough surface.
     
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  9. mtntrainman

    mtntrainman TrainBoard Supporter

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    Thanks guys. I will keep all those suggestions in mind as I move forwards (y)
     
  10. Pete Nolan

    Pete Nolan TrainBoard Supporter

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    I use a large amount of brass, which I have etched by PPD over in Scotland. My sheets are typically 12" x 15". I just pour a few inches of warm water into a kitchen sink, add a squirt of detergent like Dawn, swish them around for a while, rinse them with plain water, and let them dry thoroughly. Then I paint them with Krylon flat spray paint. Never had a problem. PPD advised me to do this wash to get any remaining chemicals or oils off the surface. When I have a number of sheets to do, I will use a bathtub, just not the one my wife uses. If I don't wash the parts, I might get a ropey surface on rails--I keep this in mind in case I want a ropey finish and want to use a lot of spray paint to achieve it.
     
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  11. mtntrainman

    mtntrainman TrainBoard Supporter

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    Thanks Pete. I think I remember hearing abou washing them in saopy water. Using Dawn rings a bell TIA
     
  12. Maletrain

    Maletrain TrainBoard Member

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    There may be a significant difference between freshly etched brass and etched parts that have been around for a time - surface corrosion or tarnish. Perhaps that is coming from the residual chemicals that Pete is washing off with soap and water, or maybe from other reasons. But, the point is that soap and water will not take off tarnish or even light surface oxidation. But, a mild acid wash will clean off oxidation. Just be sure to do it when you will be painting it soon, rather than when you receive the parts before you throw them into the back of the drawer to be used later for some project you haven't started yet. Also, I would not soak brass parts in straight vinegar overnight. A minute is probably plenty of time for relatively clean looking parts. If you need longer, I suggest that you watch for the tarnish to disappear and then remove and rinse the parts immediately. Straight vinegar could completely dissolve away some of the fine details on etched brass parts if exposed for hours. I once put a whole .30-'06 brass rifle cartridge case in a cup of vinegar and forgot about it for a few weeks - the whole thing disapeared!
     
  13. Pete Nolan

    Pete Nolan TrainBoard Supporter

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    I haven't run into tarnish as a barrier to paint. But then my brass is stored between thin sheets of paper and usually not washed until just before use. Tarnish can be a significant barrier to electrical conductivity! Except for locomotive parts, I haven't experienced tarnish as a problem, and I have some stuff from 40 years ago. Residual chemicals and oils will indeed keep paint from sticking--the ropey effect. I think Krylon (which I believe is acetone-based) cuts through any leftover oil better than enamels. BTW, i often use primer covered by an acrylic coat--depends on what I have at hand, I guess.
     
  14. r_i_straw

    r_i_straw Staff Member

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    I use gun blue treatment to give brass tooth and a flat black finish that paint adheres to quite well. I get a bottle of it at a sporting goods store. Things like brass wire hand rails, step boxes and stirrup steps are always getting bumped on my heavyweight passenger cars. If the paint gets chipped off on a corner, the bright brass on untreated pieces shows through. I suppose under bright colored paint a vinegar etch would be a better choice.
     
  15. mtntrainman

    mtntrainman TrainBoard Supporter

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    The reason I asked is that the instructions simply says to 'paint with and airbrush or aerosol spray can.

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    no mentionof prepping it.

    I srayed one fret with the aerosol spray can and let dry for about 6 hours while we took care of some other things needing done. When I cut one fence panel off the fret...the painit chipped and you could actually rub it with your finger and it would flake off. :(

    I need to get this fencing painted and planted ;)

    Thanks again for all your suggestions.
     

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