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Thoughts On Undercoating

Discussion in 'Intermediate CJ-5/6/7/8' started by dane71, Oct 16, 2018.

  1. Oct 16, 2018
    dane71

    dane71 Member

    USA
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    The guy that's doing my floor pans recommends undercoating the entire bottom to prevent chips if I'm gonna off road it, I'm thinking about only coating the wheel wells though. Would I have issues with chips behind the front wheels on the floor pans? This would be with single stage 2k acrylic paint I just bought.

    I've read a little and I'm assuming an undercoated substrate would go longer before it starts rusting, but that I wouldn't easily see and repair it once it starts. So maybe paint, keeping it clean, and fluid film will be better long term? I'm young and can easily see myself having this thing 40+ years.
     
  2. Oct 16, 2018
    Chilly

    Chilly Active Member

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    Gonna drive in snow, slush, salt, brine?
     
  3. Oct 16, 2018
    sterlclan

    sterlclan Member 2022 Sponsor

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    I’ve done rust mitigation for years I vote paint and generous applications of fluid film at least twice a year. Any undercoating or liner will eventually crack and allow moisture in but not out. I leave hat channels unsealed and allow access for fluid film applications.there are several different oil type rust preventing products I just prefer fluid film being it’s organic and biodegradable
     
  4. Oct 16, 2018
    Daryl

    Daryl Sponsor

    Bonney Lake, WA
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    All depends on your location and if you will drive in salt. I am not a fan of undercoat in most situations.
     
  5. Oct 16, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Chips = superficial rust easily spotted & rectified.

    Undercoat = trapped moisture leading to hidden rust through & a PITA to repair.
     
  6. Oct 16, 2018
    tarry99

    tarry99 Member

    Northern California
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    California Born..........1965 CJ undercoated at the dealer when new......been in the snow , dirt , mud and plenty of deep water up to the door crossings while in state and out of state hunting.......not a stitch of rust anywhere...........maybe the products were much better back then............it is a PITA to remove!
     
  7. Oct 16, 2018
    dane71

    dane71 Member

    USA
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    No salt for me, except maybe a couple days a year if I take it out snow wheeling when the roads are dry. Really good input so far, it's something to think about...
     
  8. Oct 17, 2018
    sterlclan

    sterlclan Member 2022 Sponsor

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    They were better then they had asbestosis in it.
     
  9. Oct 17, 2018
    garage gnome

    garage gnome ECJ5 welder

    Western MA
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    Undercoating... :n:

    I agree with Jeff (sterclan) fluid film works awesome. I use it on my dd with great results.
     
  10. Oct 17, 2018
    Chilly

    Chilly Active Member

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    I came into my 73 about 12 yr ago. It was well coated in undercoating, obviously applied with some regularity, but completely rotted in areas. When water gets inside the tub or tool box it needs to get back out. Gravity complicates things when the BOTTOMS of the seams are sealed but the TOPS are not.

    The flat surfaces under my Jeep looked great. The body mount flange under the floor step was completely gone, as well as other areas where water could get between spot welds and pinch welds.

    This time I'm considering chip guard on the bottom then regular doses of fluid film as stated by sterlclan.
     
  11. Oct 17, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
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    Cali don't count. :)

    I've spent enough time ithere to know that you guys just do not understand rust, it's a foreign concept to you. If you think of it at all it's as "patina".

    I spent the better part of the summer fixing rust bubbles on our '62 beetlle (that we bought in LA & drove back) that also still has the factory undercoating.

    Why did we buy a beetle in LA? Because this side of the rockies they all turned to rust a long time ago, that's why.
     
    jarhead6153 likes this.
  12. Oct 17, 2018
    tarry99

    tarry99 Member

    Northern California
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    Oh we understand here............but deal with it in a much different way in how we make our choices.........I've had plenty of Cally born cars that also partially rusted away due to unprotected metals........and when faced with that restoration.........I either moved on if there was other choices or started the rebuilding process.........I've also bought and looked at allot of original restoration parts from the East ...........and your right for what we normally throw away the Easterners think it's Cherry!...............and they dumped Salt on our roads here tell probably the late seventies maybe early 80's
     
  13. Oct 17, 2018
    Daryl

    Daryl Sponsor

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    What is rust free to a guy from Michigan is a rusted out hulk to a guy from California.
     
  14. Oct 17, 2018
    sterlclan

    sterlclan Member 2022 Sponsor

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    it, like most things is all perspective. around here they rust in three years in five im putting rockers and corners on them around eight the brake lines and fuel lies fall off at ten the frame is toast. all preventable with some sort of oil-ish coating.
     
  15. Oct 18, 2018
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    When my dad bought the Tux back in '65, the first thing he did was have it undercoated, with Texaco grease! There was a place that sprayed grease with an Alemite wand setup and coated everything with a heavy amber grease. In 10 years of splashing though the surf, it was nearly rusted away by the time I got it. The cowl and hood were the only parts I was able to save of the original body. In normal situarions, the undercoat probably would have preserved the Jeep fairly well, but the salty beach was too much. The Chevy wagons he had grease undercoated back then held up really well with the salted roads of Ohio where I grew up.
    -Donny
     
  16. Oct 18, 2018
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

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    The thing with grease/oil/wax coatings is that they have to be renewed every year.
     
  17. Oct 18, 2018
    Dave Deyton

    Dave Deyton Member

    Fuquay-Varina, NC
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    We lived at the coast of NC when I grew up. We had a 66 Wagoneer that we drove on the beach all the time. It rusted away badly. My father bought a 77 Blazer and had it Ziebart rust proofed. They sprayed the rust proofing in the panels and put plugs over the holes. The only rust was from chips in the paint and I repaired them. When he traded it in on a new Wagooner, the service manager took it home because it was in such nice condition.

    I think a creeping or liquid film would work best because it would re-seal itself. I have heard of people undercoating an older car and it rusted faster because it held in the moisture.

    Dave
     
  18. Oct 18, 2018
    sterlclan

    sterlclan Member 2022 Sponsor

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    Twice a year is my prescription
     
  19. Oct 18, 2018
    earlswrench

    earlswrench Member

    Atlanta, GA
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    To be specific, what are we talking about when you're saying "undercoating?" Are we talking about the rattle can black spray or two-part, spray-in bed liner? I'm about to paint and my plan was to use Raptor Liner on the inside floor and underside of the tub. Do y'all think this will also lead to premature rusting by holding in moisture? Seems like this stuff is pretty tough. When I tore down the tub, it had a cheap spray-can undercoating that was old, dry and flaking. I could definitely see where that would be a long-term problem.
     
  20. Oct 18, 2018
    tarry99

    tarry99 Member

    Northern California
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    Any spray on Finish regardless of type is only as good as the preparation to the base metal..............
     
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