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Help - paint mismatch & rust repair advice pls?

  • 10-05-2020 10:09am
    #1
    Registered Users Posts: 1,039 ✭✭✭ MrCostington


    Hi, I posted the start of this little project in the DIY section, but putting the follow up here as there should be more experience with older cars here.

    On the roof gutters there appeared to be some rust, my original post here:

    https://www.boards.ie/vbulletin/showpost.php?p=112156908&postcount=10

    So I finally tackled one side last Monday, and made a bit of a mess I think. I removed the paint to bare metal with a drill and wirebrush. Turned out there was no rust whatsoever, it seems it was just dirt in a crack in the paint. So I put 3 coats of zinc primer and 3 or 4 topcoats. I have not applied the lacquer yet.

    The topcoat is a can made up from the paint code (EDIT MB 930 silver blue metallic - can says multicrly spraymatch/tint) and seems to be a poor match (or maybe I just did a crap job). I'm thinking that maybe the colour would match if the car was new, but maybe the paint faded over 37 years?

    Anyway, is there anything I can do to improve it before applying the lacquer, such as Tcut etc? And for the lacquer, should I try to just do the small area around the new paint, or be brave and spray a bigger area?

    paint1.jpg

    paint2.jpg


    Second question, there is some rust spots on the sunroof (keys for scale). After this experience I'm thinking my best course of action is to remove the rust and apply treatment (should I then sand that?), then apply primer and topcoat by using a brush instead of spraying, would that look better? Any advice please? Thanks :)

    sunroof.jpg


Comments

  • Moderators, Home & Garden Moderators Posts: 4,746 Mod ✭✭✭✭ kadman


    Primer colour can also affect the colour of the top coat, I have noticed when I

    have used cellulose on my cars. Darker primer colours give a darker top coat finish,

    and lighter primers, give a lighter top coat finish.

    Its almost impossible to see the difference from a small pic here. Different angles on paintwork

    also give flip tone and side tone views, showing different colours.

    I dont know what paint MB used on their cars, wait for some MB owners to chime in


  • Registered Users Posts: 1,039 ✭✭✭ MrCostington


    Thanks kadman, I edited the OP to include the colour MB 930 silver blue metallic - can says multicrly spraymatch/tint.

    The primer is fairly dark, but this being my first time painting, I'd guess it's not the darkest (it's Isopon zinc 182 says grey as colour).

    I don't think it's the primer though, as what I did was mask very close to the bare metal and apply primer. Then I peeled back the masking about 2cm and applied the colour to the primed area, and the existing paint. So, the line between old and new does not have primer under it.

    On my laptop screen, the new paint goes from the bottom to about one thumb width from the top of the rubber trim, if you know what I mean. I tried taking several pictures but the ones I posted show it best, in person it's easy to see (if looking for it).

    "also give flip tone and side tone views, showing different colours." - what do you mean by that?


  • Moderators, Home & Garden Moderators Posts: 4,746 Mod ✭✭✭✭ kadman


    Flip tone and side tone is basically looking at 90 degrees to a surface or tangentially to a surface,

    think of looking at a door panel, and looking at a roof surface.

    With a small area to spray, you need to fog in or mist lightly to blend into existing paint to

    camouflage where they meet together. This hides any variation in shade.

    Painting up to a masking tape leaves a definitive border in both colour and depth of paint.


  • Registered Users Posts: 1,039 ✭✭✭ MrCostington


    Ah, ok I see, I'll try to take better pics later today, thanks.

    Do you think I should go over it again? I just did not have the confidence to go fully free hand and not mask it. Would Tcut or similar help do you think?

    Any suggestions re my sunroof?

    Sorry to impose!


  • Registered Users Posts: 3,093 ✭✭✭ hi5


    The sunroof is a 'touch up' repair.
    Chip the paint back slightly until you have clean metal
    Use a fiberglass pen to clean the surface rust off.
    Then a drop of rust remover to get down into the pores of the metal, let it dry.
    Then a dab of primer and paint.


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