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VHB tape Fail

Discussion in 'Installation Equipment & Techniques' started by ScottyAdams, Aug 16, 2012.

  1. ScottyAdams

    ScottyAdams Member

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    Hey Guys,

    So I used some VHB tape (3M 4910) on some 1" D-Ring hangers applied to the back of some Dibond Alupanel (20"x20" and i think 3mm thick) material that I had applied a print to with framing wire between the two hooks. After 10 minutes of hanging on the wall, the VHB tape failed and the whole thing came crashing down, leaving me with a damaged piece of dibond with bent corners. I used about a 1" x 1/2" piece of tape on the back of each hanger. My questions are:

    Is this the wrong kind of VHB tape to use for this application?

    Is there a minimum surface area that the VHB must cover to have the holding strength it is rated at?

    What else should I try using for this sort of thing (previously i used a bit of clearweld epoxy which worked great but took hours to dry and overnight until it could be hung up)?

    Thanks for any help and information!!:thankyou:
     
    Tags:
  2. Replicator

    Replicator Major Contributor

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    epoxy, glue, etc . . .
     
  3. Billct2

    Billct2 Major Contributor

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    From what I understand many tapes have a "cure" time. The bond gets stonger after it's been on a while. May want to ask the tape manufacturer if there is a "set" time. You could also consider french cleats which would have a lot more surface.
     
  4. Scott Reynolds

    Scott Reynolds Active Member

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    THAT! Or THIS! Which ever you prefer.

    VHB gets stronger to longer it sits. A day or two and its on there hardcore. Also, was the VHB sideways or vertical? 1/2" VHB is going to much stronger vertical than horizontal. You should cover the whole back of the D ring (1"x1") and maybe a dab of primer to the dibond to shorten the "set" time of VHB.
     
  5. ScottyAdams

    ScottyAdams Member

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    I left the VHB tape sitting over night. The VHB tape was on the entire back of the surface area of the hangers and they were applied at the same angle as the wire once hung if that makes sense.
     
  6. SignosaurusRex

    SignosaurusRex Major Contributor

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    Application/Installation Failure. Not the VHB. 3M 4910 does not fail when used properly. That is why it costs so much. You should have used an epoxy. 1 sq. inch of VHB to hold 400 sq. inches of 3mm Dibond?
     
  7. crystalcoastgraphics

    crystalcoastgraphics Member

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    We always tape prime first, and then allow to sit overnight. Never had a failure yet!
     
  8. i slice the hell out of it after i pull of the backer, this minimizes the zipper effect.
     
  9. Mosh

    Mosh Major Contributor

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    What was the size/per VHB you used. The ONLY prblem I have ever had with VHB is getting is back off after installed. You need alittle more thane 1/2 long piece. 20"x20" should have at least four to six 1"x1" squares and not on the "d" rings on the aluma itself. The suff is great, but not magic holding!
     
  10. Techman

    Techman Major Contributor

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    right on....
     
  11. Moze

    Moze Very Active Member

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    It's also a pressure sensitive tape. 3M specs say to apply pressure for about 20 - 30 seconds I believe it is, across the entire surface of the tape used. That's a bit overkill in my opinion, but the goal is to get the tape to wet out. If there are areas that don't wet out, the tape can gradually pull loose if there's sufficient pressure on it.

    Another thing to be aware of is if the install surface has been painted recently, it has to outgas for a couple/few days before you can apply tape to it. Otherwise the gasses in the paint can cause the tape to release from the surface.
     
  12. SignProPlus-Chip

    SignProPlus-Chip Active Member

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    I used VHB for years, hell decades even, and never had it fail. We used to used it to bond aluminium plate together when I worked in a machine shop.

    The most common reason for VHB failing is lack of surface prep. Needs to be degreased and applied to a clean surface. The smallest amounts of oil, grease etc... can inhibit the bond.
     
  13. vid

    vid Very Active Member

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    wow --- I am so ashamed. :banghead:


    That is such a stupid-simple trick --- I should have thought of it long ago. Thanks for that epiphany. :notworthy:
     
  14. TXFB.INS

    TXFB.INS Very Active Member

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    thanks for the neat trick! will be using that one


    +1
    we also use heat when possible to active the adhesive as well as the constant pressure for a good 30 secs
     
  15. nwsigns

    nwsigns Member

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    I prefer Lords adhesive or something similar - it will peel the skin off the Dibond before letting go.
     
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