viscoelastic adhesive

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I am searching for some viscoelastic glue (or sheet) for constraint layer construction. I found Green Glue in my web searches and also used it. It uses water as a solvent (no VOC) but it therefore works only with material which can absorb water like wood, MDF or gypsum board. It also has a quite low adhesive strength. I would like to use it on aluminum or composites. I assume that the new Magico Q series uses some constraint layering otherwise these speakers would ring in spite of their fancy bracing.
I could find some polyurethane glues which are elastic but not viscoelastic.
 
I am still looking for a viscoelastic glue. Vibratec is unavailable in the US. Swedac has 2 products: DG-06 (2 component PU) and DG A2 (water based acrylic) but I did not find any supplier either. I have tried Green Glue but it is not working very efficiently in constrained layer. It is not a glue (but green) and is designed for plaster board (2 layers held by screws). Wall damp is identical in these properties.
Many constrained layer constructions use elastic glues/layers (e.g. silicone, rubber) but viscoelastic layers are much more effective. An alternative would be a thin viscoelastic sheet but most I have found are relative thick and loaded with some additives to add mass.
 
Try the 'inverted moquette'
It is the carpet with gummed base, attached to the walls of the cabinet
not by the base but by the fluffy side :)
So the gum sheet is free to absorb & flex ;)

There are a lot similar approaches for speaker building (like Black Hole 5) or for automotive applications. Most include (visco)elastic layer(s) with some mass loaded layers but any of these are not what I am interested in: constrained layer cabinet wall construction.
One option would be to coat 1 or 2 sides with a viscoelastic spray like Cascade VB-1S PRO Quiet Kote Damping Spray or similar product (thin coat - 1mm thick). When these coats are dry one glues the 2 layers together with PU. Has anyone experience with that approach?
 
I am still looking for a viscoelastic glue. Vibratec is unavailable in the US. Swedac has 2 products: DG-06 (2 component PU) and DG A2 (water based acrylic) but I did not find any supplier either. I have tried Green Glue but it is not working very efficiently in constrained layer. It is not a glue (but green) and is designed for plaster board (2 layers held by screws). Wall damp is identical in these properties.
Many constrained layer constructions use elastic glues/layers (e.g. silicone, rubber) but viscoelastic layers are much more effective. An alternative would be a thin viscoelastic sheet but most I have found are relative thick and loaded with some additives to add mass.
Try contacting Swedac directly - it's a small service minded company.
A2 is told to be very effective in constrained layer cabinets.
 
IF .. serious, one could look into construction adhesives.
As even a rudimentary start point.
For example: structural glazing utilises a variety of silicone adhesives with distinct and varying Modulus of Elasticity properties.. up to and past 100% even .
PolyU caulks/glues are another. Lotsa choices actually
Time to do some ernest looking ?
 
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Roofing Felt

I am searching for some viscoelastic glue (or sheet) for constraint layer construction. I found Green Glue in my web searches and also used it. It uses water as a solvent (no VOC) but it therefore works only with material which can absorb water like wood, MDF or gypsum board. It also has a quite low adhesive strength. I would like to use it on aluminum or composites. I assume that the new Magico Q series uses some constraint layering otherwise these speakers would ring in spite of their fancy bracing.
I could find some polyurethane glues which are elastic but not viscoelastic.

... constrained by masonite sheet. See URL: Loudspeaker construction

Did not read the other posts here; just a quick response.

Regards,

WHG
 
Most of the better constrained layer damping sheets for cars use butyl with a thin layer of aluminum.
The butyl products stay elastic, most asphalt based products dry out eventually.
It (butyl) sticks very well but I don't think its a substitute for glue. It does do the job gluing the sheets
to a car door and keep it there for years though.
 
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