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gobo gluing issue

Discussion in 'Room Acoustics / Isolation / Treatment' started by larrytheo, Jun 10, 2016.

  1. larrytheo

    larrytheo Active Member

    I built myself three 4 ft x 6 ft gobos, each made from a framed piece of ¾ inch plywood, a layer of 1/8 inch high-mass vinyl, and three 2x4 batts of acoustical/fire rockwool. Each batt is wrapped first in light tracing paper to keep fibers in, then all the batts are wrapped in theatrical polyester muslin fabric, which is durable and fire-resistant, if not entirely acoustically transparent.

    I glued the batts to the high-mass vinyl using either Scotch 77 spray adhesive or Scotch 90 (rubber and vinyl). It was several years ago, so I just don't remember. In any event, two of the three gobos have remained glued just dandy. The third has not. The batts started pulling away from the vinyl, so I tried regluing it using Scotch 77. I was pretty liberal applying the spray adhesive and gave it a few minutes to get tacky before I put the batts in the frame and glued them to the vinyl.

    That lasted only a short while before it started coming off again. This time I tried a good bit of Scotch 90, but that hardly lasted a day or two. I'm not sure how to get these batts to stick. At this point, I'm afraid there's a lot of old glue goo that might be working against adhesion, but it's going to be very hard to remove it. I might be able to reverse the muslin so there is less glue on it, but I do not have access to more of this muslin, so I can't just get another piece.

    Anyone have any suggestions?

    Thanks!
     
  2. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    I'm wondering if maybe a commercial grade Velcro would do the trick. Maybe staple it to the vinyl/plywood, and stitch it to the fabric which is wrapping the panels?

    I've never done this, so I couldn't guarantee anything. Just thinking aloud. If worse came to worse, you might be able to use a really thing string or thread and tie it together, which if the string is thing enough might not be visible. Maybe you could just re wrap the panel, and re glue? Once that glue hardens, re application of glue never works well. I would imagine it's because all the little fibers and holes, become effectively smooth and solid.

    Perhaps maybe a painted screw and washer combo would hold them in there.

    You could also nail thru the side of the plywood, or put a trim on the front face to extend it, put finish nails through that to retain the fiberglass by there front face, and then put more fabric to cover up the nails.

    If you used a trim that was wider than the 3/4" edge of the frame, it would retain the fiberglass, and not require more fabric. You may want to modify all of them for continuity of look.

    Chicken coupe wire over the front could work too, albeit while reflecting a little bit of highs, which would be negated a bit by covering with fabric.


    Sorry I don't have an actual straightforward solution for you on this one. It's not a problem I've encounter before.
     
  3. larrytheo

    larrytheo Active Member

    Thanks, kmetal, that's a bunch of good suggestions. I think I might try the velcro. It's a simple and cheap solution that will have no cosmetic impact and not require any modification of the gobo structure.

    It's not a problem I've encountered before, either!
     
  4. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    Good luck buddy, let us know how it works, or what you end up doing.

    Cheers!!!!!
     

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