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Panel bonding roof skin

Discussion in 'Tech Tips' started by Steamfitter87, Sep 6, 2017.

  1. Steamfitter87

    Steamfitter87 New Member

    Replacing the roof skin on a 98 dodge ram. It was recommended that I use panel bonding adhesive to bond the new roof skin on. Once I get the new skin on aligned and clamped in place do I still need to plug weld the skin on? It seems a lot of research I've done shows plug welding after it's bonded.
     
  2. crashtech

    crashtech Combo Man

    Plug weld, don't glue the front and back window openings, and don't use glue within 2" of where welding will occur, otherwise the glue will contaminate the welds, light on fire, and generate hazardous fumes. Welding the window openings is to help maintain structural integrity, the windshield in particular is part of the structure of the cab and works with the restraint system in a collision. Roofs that have been glued under the windshield have been seen to separate in a collision with bad results.
     
  3. Steamfitter87

    Steamfitter87 New Member

    Thank you for clarifying that makes sense. Do you worry about the area between the two layers of sheet metal rusting in that area? I don't know how I could get access to that area to epoxy it after it's welded up.
     
  4. crashtech

    crashtech Combo Man

    The method that seems to get approval on this forum is to epoxy both sides before welding, then clean out the plug weld holes with a cut-off drill bit just prior to welding.

    I use various methods depending on the coating and condition of the parts being welded. I-CAR and vehicle manufacturers mandate the use of zinc-rich weld-thru primer in some circumstances, especially where sanding or grinding has removed factory galvanneal or galvanizing. Domestic vehicles like your Dodge should have galvanneal where factory coatings are not disturbed.

    Some coating should be applied in the pinch weld, that much we all agree on.
     
  5. jlcustomz

    jlcustomz evil painter

    Glues like 3-m 8115 are some of the strongest metal glues I've seen, strong enough to sometimes have the metal rip rather than the glue. BUT if you were to read the product directions, it would say not for structural use.
    Factory parts designed for adhesive use large flanged areas to properly make use of the product.
    Also , 400 degrees is about the point of removing an epoxy product, which is why you can't weld right at it.
     
  6. DATEC

    DATEC Member

    State Farm is now being sued for telling a shop they had to glue a roof on and then afterwards the car was hit hard and the roof became unglued and the cars structural integrity was severely compromised and the car folded and killed he driver. Anyone who said that needs a really hard punch on the face. I have seen glue on bedsides become unglued and easily pulled off when I was working on the repairs, that was the fastest bedside removal I ever did. NEVER EVER glue a structural part of any car ever unless you have the $21K spot welders used with the glue.

    https://www.fenderbender.com/articl...farm-after-repair-traps-driver-in-burning-car
     
  7. Steamfitter87

    Steamfitter87 New Member

    Thank you for the quick replies. Very informative. One of the many reasons I like this forum so much.
     

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