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Technical Another panel adhesive question

Discussion in 'The Hokey Ass Message Board' started by KenC, Sep 28, 2020.

  1. KenC
    Joined: Sep 14, 2006
    Posts: 473

    KenC
    Member

    I posted the following in another thread. I don't think that one got a lot of looks so I'm reposting here. Hijacking threads like I did never works well.
    \
    Concerning 3M or other panel adhesives: I have a possible use for that stuff, see what you think:
    My56 Dodge PU has the normal rust in the front fender, vertical strip next to the edge of the rear. To do a 'proper' repair would mean a complete rear edge replacement. That means a bent strengthening lip on a curved edge that must match the door curvature. Not easy for me to do. So, I was thinking of trimming off all the really thin stuff, sandblasting the inner surface and applying a patch to the back. That way I could use the very rear of the original to maintain the curve, and meet the door. Then grind off any exposed adhesive and finish with Kitty Hair filler, Rage and primer.

    The finished filler would only be the depth of the original metal thickness.

    Whatcha think?
     
  2. BJR
    Joined: Mar 11, 2005
    Posts: 6,517

    BJR
    Member

    It might work....... for a while.
     
    Tman likes this.
  3. pkhammer
    Joined: Jan 28, 2012
    Posts: 549

    pkhammer
    Member

    I have used 3M DP810 epoxy on projects at my workplace where welding is not a good option. It works extremely well on parts that have a good fit (no gaps) but I'd still prefer welding in a patch if possible. I'm not sure how the vibration/movement of a body panel would effect the bond over time. It seems to me spot welding would be an option to consider.
     
  4. KenC
    Joined: Sep 14, 2006
    Posts: 473

    KenC
    Member

    A little info please. What would you expect to fail? Rust come back 'cause I didn't prep it well? Or adhesive to turn loose? Maybe a show through at the lap? The last is my fear.
     

  5. Dino 64
    Joined: Jul 13, 2012
    Posts: 1,879

    Dino 64
    Member
    from Virginia

    I’ve used 3m panel adhesive with good results, read the instructions, I think filler over the adhesive is a no no
     
  6. What he means is that is a hack repair. Do it right or do it again sooner rather than later
     
  7. I tried to say that very thing in the last thread he asked the same thing tman



    Sent from my iPhone using H.A.M.B.
     
    Tman likes this.
  8. coilover
    Joined: Apr 19, 2007
    Posts: 616

    coilover
    Member
    from Texas

    Have had very good results with panel adhesive even on stress areas where it isn't recommended. On non stressed areas it saves much time and has zero warpage. Used to take a week to smooth a really riddled firewall that can now be done overnight. Did a tudor Model A roof insert eight years ago and a termite special 34 Chevy Town Sedan six years ago and both have no issues.

    A insert has ribs to strengthen and cut vibration:
    IMG_4335.JPG



    34 Chev has smooth insert:
    IMG_4787.JPG
     
    DdoubleD likes this.
  9. 2OLD2FAST
    Joined: Feb 3, 2010
    Posts: 2,728

    2OLD2FAST
    Member
    from illinois

    While certainly not the same this reminds me of when plastic plumbing pipe started to be used ,it won't last , the glue will deteriorate ,the plastic will get brittle , it won't hold up to hot water , etc , etc . the world will come to an end ! Not only is plastic pipe & the adhesive still being used , as an example , mine has been in service for over 40 years ! The only way to find out is to use it ! Take what all the naysayers say with a critical eye ...
     
  10. When kitty hair is mentioned the end result is always wrong
     
  11. KJSR
    Joined: Mar 7, 2008
    Posts: 2,298

    KJSR
    ALLIANCE MEMBER
    from Utah
    1. Utah HAMBers

    I wonder how many the people doubting the repair method have actual experience. I have actually used epoxys for body repairs and have had good luck.

    The most important part is the prep (as with any repair) and it seems like to you have a good plan.

    Filler over the epoxy is fine but it needs to be prepped properly for the filler to adhere. I have no experience with "kitty hair" but there are many fillers with fiberglass added.
     
  12. Filler over panel adhesive is not fine. I work for a filler company and that would never be an approved process (@lippy posted that 3M said it was not an acceptable process as well when he called them) and I have seen it fail on numerous occasions even when "prepped properly".

    Luck is not a good methodology for suggesting or following product recommendations because eventually it runs out. I see it everyday. "I have always done it this way" has to be the phrase I hear the most when I get calls about product failures and it's probably about 99 times out of 100 that their methods were incorrect and they had been lucky up to that point in time.
     
    Last edited: Sep 30, 2020
    Dino 64 likes this.
  13. Well, I have also used adhesives IN THE RIGHT APPLICATION. I also know and have done proper metal repair. in both classics and late models. There is no easy shortcut to a repair that is done well and will last.
     
  14. whiteknuckle
    Joined: Feb 6, 2007
    Posts: 42

    whiteknuckle
    Member
    from Dryden, NY

    I used 3M adhesive to put full quarter panels on a Mustang GT350 clone over 15 years ago for a guy. It is driven regularly in decent weather in upstate NY and there is no evidence of a seam all these years later. Read the instructions, do the prep correctly and if used as intended the adhesive products can do a great job.
     
  15. KenC
    Joined: Sep 14, 2006
    Posts: 473

    KenC
    Member

    Good to hear. My 97 F150 has an alumimum hood with braces 'glued ' in place also has the roof panel glued on from the factory. Only 23 years of testing, but seems ok so far.
     
  16. KenC
    Joined: Sep 14, 2006
    Posts: 473

    KenC
    Member

    I never mentioned filler over adhesive as I specifically stated the adhesive would be ground away.

    The instructions specify clean, properly prepared metal.

    My mention of 'Kitty Hair' just refers to the generic nickname for fiberglass reinforced filler. I guess in my case it wouldn't be needed on second thought. It is often used over welds that may have some porosity because it is more water resistant that finish fillers, and have some strength if used in thicker layers. Neither would be needed in my repair.

    Still thinking it over, may weld it up, but that would probably mean an investment in a shrinker/stretched to get the curve right. This fender has a lip about 1.25 inches wide, bent about 135deg. Bending the lip is easy, putting the convex curve back into the repair after the lip bend may require the new tool. I'm just not good enough with hand tools to do that reliably. I've seen some similar done with notches, saw cuts etc. That is a hack repair even if welded and new metal used, IMO.

    The reason I ask about experiences with adhesive repairs is because I don't want a hack repair as someone mentioned. but, if the glue works permantly, it's not hack.
     
  17. And I didn't quote you that you did. I quoted another member who said it was ok. If you are not already set up for the adhesive you will probably be into it for not much less money as an inexpensive shrinker.
     
  18. BJR
    Joined: Mar 11, 2005
    Posts: 6,517

    BJR
    Member

    I would expect it to shadow or maybe even crack within a year or until you paint it.
     
  19. DdoubleD
    Joined: Nov 18, 2009
    Posts: 222

    DdoubleD
    Member
    from Michigan

    I love reading all the input from the "experts" when it comes to this subject. LOL
     
  20. Let’s see pictures, I’m very familiar with those trucks and everyone I have seen that folded edge is fine, they rust in from it, mine had patched welded in an the factory edge was left intact, then it’s almost a flat piece


    Sent from my iPhone using H.A.M.B.
     
  21. Let’s see pictures, I’m very familiar with those trucks and everyone I have seen that folded edge is fine, they rust in from it, mine had patched welded in an the factory edge was left intact, then it’s almost a flat piece


    Sent from my iPhone using H.A.M.B.
     

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