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Shooting (seam sealer) in the hood

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  • Voyce
    • Oct 29 2022
    • 201

    Shooting (seam sealer) in the hood

    Had a hood nose cancer repair job on the Bird list.

    Upon removing the hood, one could really see the lost adhesion of the seam sealer disposed between the inner ribbed hood support stamping and the outer hood stamping. (After 60 years, you would lose some of your grip too.)


    However, the sealant had hardened to the point that in many, many spots it was only sticking to one side of the metal sandwich or the other. Worse, surface corrosion was starting to appear on the loose seam side. Then, there is the issue as to how much the lack of fully sealed frontal seams contributed to the nose cancer.

    So, out came the putty knife. Every old seam sealant was loosened, creating handfuls of hard sealant in all shapes and sizes, all conveniently stuck between the two stampings.

    So, out came the compressed air blaster. Much air, much turning, much grabbing, much fun?
    Now, time for the replacement seam sealant, an elastomeric urethane having a hard rubber functionality upon cure.

    So, out came the caulking gun. Tubes of sealant, circumferentially placed about all of the seam openings on the underside of the hood, using a solvent seam smoothing action:

    dataurl734613.jpg

    Luckily, the hood repair already put a repaint on the list. A few coats of color and a few coats of clearcoat:

    dataurl734612.jpg
    (Of course, the topside cancer was fixed, and it was repainted too.)

    Time to re-marry the hood and hinges. No more torsional movement between the stampings.

    dataurl734611.jpg
    Listen to that solid sound when the hood is closed!

    Who knew that shootin’ in the hood could be so rewarding?

    (No bystanders were injured in the restoration of this hood.)
  • simplyconnected
    Administrator
    • May 26 2009
    • 8909

    #2
    The factory didn't seal hemmed seams unless they potentially let water into the cabin, like cowl baffles that let air in. Spot welds are somewhat inhibited from going through sealer. They do however, put dollops of sealer between the inner and outer hood panels and 'door guard reinforcements' to eliminate sheet metal flutter. (when the car goes through the Sealer Deck). Primer Ovens cure the vinyl sealer before base coat is sprayed in 'Paint'. Back in the day, there was no such thing as clearcoat. So, you will notice that the sealer you removed was also painted.

    Nice job! Your hood is MUCH better than the factory job, now. Rust holes in the front of the hood are very common among all classic cars, especially in the North or places that get lots of rain. - Dave
    Member, Sons of the American Revolution

    CLICK HERE to see my custom hydraulic roller 390 FE build.

    "We've got to pause and ask ourselves: How much clean air do we need?"
    --Lee Iacocca

    From: Royal Oak, Michigan

    Comment

    • Dan Leavens
      Moderator / Administrator


      • Oct 4 2006
      • 6489

      #3
      Voyce great restoration on your hood. Well done. Regards
      Dano Calgary,Alberta Canada
      Thunderbird Registry
      58HT #33317
      60 HT (Sold )

      Comment

      • Voyce
        • Oct 29 2022
        • 201

        #4
        Dave:

        You are correct again. The old seam sealant was factory painted on its exposed faces.

        Thanks for the kind words.

        My main purpose in the above posting is to remind us all that no one at FoMoCo expected these Birds to be driven six decades later. I am confident that when the engineers selected the sealant material, they did not have that life cycle in mind. Nor did they have a moisture curing urethane available that remains flexible upon curing. A material that can absorb vibrational energy from the hood stampings.

        It sneaks up on you. Your hood seam sealant may not be doing its job anymore. With the hood removed, it was enlightening to see how much movement there was between the stampings due to the failure in the aging adhesion of the sealant. Once the repairs were made, then you could easily determine how much firmer the hood was, how much proper sealant adhesion assists hood functionality.

        So, to fellow stewards, think about checking out your Bird. How is your sealant doing “in the hood”?

        Dan:

        Thanks for the kind words.

        It was a lot of effort, but the reward lies in feeling and hearing the revitalized hood in action. It really sounds and feels different.

        One added detail I failed to mention can be seen in this image:
        dataurl965208.jpg
        We inserted rubber plugs in the row of holes in the lower stamping, at the front of the hood. Just gives it a more finished touch.

        Comment

        • Anders
          Super-Experienced
          • Jan 19 2008
          • 2225

          #5
          "an elastomeric urethane having a hard rubber functionality upon cure"
          Looks great!
          What type / brand did you use?

          sigpic..."Lil darling Ruth"
          http://www.tbirdregistry.com/#33158

          Comment

          • Voyce
            • Oct 29 2022
            • 201

            #6
            Anders:

            I used a 3M automotive product. As you can see from this link (3m-urethane-seam-sealer-tds-08362-08365-08367-08368.pdf), it is available in a variety of colors.

            I use xylol for a finger smoothing action.

            Thanks for asking. I would say it provides a good binding function with an ability to absorb vibration.​

            Comment

            • Anders
              Super-Experienced
              • Jan 19 2008
              • 2225

              #7
              Thanks for the answer! Looking at the picture on post #4, I have another question: What band or cord is it next to the hinge there? Some kind of "stop-security" or what? Or is it a ground? Is that original? And in what material? Never had one in my ´58.
              Last edited by Anders; July 19, 2024, 03:38 PM. Reason: Spelling...
              sigpic..."Lil darling Ruth"
              http://www.tbirdregistry.com/#33158

              Comment

              • Voyce
                • Oct 29 2022
                • 201

                #8
                Anders: You are quite observant.

                That shiny strap is an addition I made. It is simply an EMI-reducing grounding strap with lug connections. I had it on hand. It is NOT original.

                At the time I replaced the hinge springs, refurbishing the complete hinge assembly, (thanks partsetal Carl!) and decided to add it for better radio reception.

                For hood security against accidental closing, I use my Bird stick.

                Brian

                Comment

                • Anders
                  Super-Experienced
                  • Jan 19 2008
                  • 2225

                  #9
                  Originally posted by Voyce
                  It is simply an EMI-reducing grounding strap with lug connections. I had it on hand. It is NOT original.

                  At the time I replaced the hinge springs, refurbishing the complete hinge assembly, (thanks partsetal Carl!) and decided to add it for better radio reception.

                  For hood security against accidental closing, I use my Bird stick.

                  Brian
                  Nice. Think I will steal that idea instead of that little brittle piece of copper or brass that was between the body and hood on my car.
                  sigpic..."Lil darling Ruth"
                  http://www.tbirdregistry.com/#33158

                  Comment

                  • simplyconnected
                    Administrator
                    • May 26 2009
                    • 8909

                    #10
                    It's a good idea to add a #10 stranded copper wire between your NEG battery post and the firewall (when the battery is up front). Modern cars use a short green wire, usually fastened to the radiator support.
                    Member, Sons of the American Revolution

                    CLICK HERE to see my custom hydraulic roller 390 FE build.

                    "We've got to pause and ask ourselves: How much clean air do we need?"
                    --Lee Iacocca

                    From: Royal Oak, Michigan

                    Comment

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