White spots on polished aluminum hood

Discussion in 'Peterbilt Forum' started by mile marker 27, Aug 14, 2022.

  1. mile marker 27

    mile marker 27 Medium Load Member

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    1AB05792-FF73-45B8-BC4E-99DA697D71E2.jpeg FD751C12-E006-4E19-9F44-E1B06A1068DE.jpeg The hood sides on my ‘87 379, are in the process of getting polished. I started the process last winter and took it to point but not quite as shiny as I would have liked. I decided to start back on it, and noticed it had a lot of very small white spots. You can’t feel them, can’t wash them off and they wouldn’t buff out. As far as I know me or my FIL haven’t sprayed anything close to the sides but it looks like some kind of liquid has been sprayed on each side. Is it just oxidation and how can I remove them without sanding?
     
    Rideandrepair and Boondock Thank this.
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  3. Boondock

    Boondock Road Train Member

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    Did you try rubbing compound?
     
    Rideandrepair Thanks this.
  4. Coolbreezin

    Coolbreezin Light Load Member

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    I have a custom chopper and Ive battled white spots. Mine came from hard well water. If you want your metal to shine, youll have to sand it. Try wet sanding starting with 1500 grit and go up to 2000. The follow with polish designed for that metal.
     
  5. Catmando

    Catmando Road Train Member

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    Spray it with white vinegar.. and see if they will wipe off about 15 mins after your spray them
     
    Boondock, Rideandrepair, Oxbow and 2 others Thank this.
  6. mile marker 27

    mile marker 27 Medium Load Member

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    I used a 3M and a Zephyr rubbing/buffing compound.
     
    Boondock and Rideandrepair Thank this.
  7. mile marker 27

    mile marker 27 Medium Load Member

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    I’ve washed this truck, with this same water several times before and never had this happen. That’s what’s strange. This truck has newly polished wheels, washed with the same water and there’s no white spots on them.
     
  8. wore out

    wore out Numbered Classic

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    I don’t have an explanation as I would think aluminum is aluminum. I know that wheels and tanks stay polished without a treatment per say. Maybe the body panels are softer composition but every time I have seen them polished they do that. I think it’s the start of corrosion. I also think that once it starts under the paint the only way to fix it is replace that panel. It always comes back in time. Naturally I wouldn’t think that your hood is bad enough to replace them to stop it. I’d say take a DA sander and 800 then 1000 then polish. Honestly everything needs cut from time to time especially the wheels on a cow mobile
     
  9. Catmando

    Catmando Road Train Member

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    OP .. exactly what pieces are your talking about on the hood ?.. the small side pieces that bolt on to the cowl ?
    Or the actual side sheets on the hood ???
     
    Boondock and wore out Thank this.
  10. mile marker 27

    mile marker 27 Medium Load Member

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    The trucks tanks are painted in the centers but end caps and bands are polished. The end caps got polished last Wednesday and had spots on them too(front sides only) yesterday. Definitely ahead scratcher.
     
    Boondock, Rideandrepair and wore out Thank this.
  11. mile marker 27

    mile marker 27 Medium Load Member

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    56A9327B-E5BB-443F-820B-5C8E939EF4B3.jpeg
    side panels, and this pic is from last winter. No signs of these spots until 2-3 days ago.
     
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