Adhesive for Constrained layer damping with nonabsorbent panels

I was building small panels for my drivers using sheets of aluminum (4mm) and Richlite (8mm). The adhesive I used was 2 component urethane (Loctite UK U-05FL) which supposed to have some viscoelastic properties but it comes only in 50ml cartridges. These panels are quite dead, more than a similar panels with Richlite and baltic birch plywood and both versions obviously much less resonant than plywood (including bamboo) alone.
Searching for adhesives for CLD I found often recommendations for green glue (tried it myself) or Swedac. These are water based products and work with drywall or wood derived panels but never cure with nonporous materials. Other recommendations are caulks like for instance Weicon flex 310 PU but thesis cure through air exposure and will cure only maximum 25mm in nonporous materials.
VHB tape would work but gets expensive for larger surfaces and I would prefer adhesives for assemblage. Also I like to avoid adhesives which are available only in large containers like Decidamp DC30.
 
for Weicon see: https://assets.weicon.de/#/asset/306597
Sikaflex 11Fc is moisture cured so needs air access to cure https://usa.sika.com/content/dam/dms/us01/6/sikaflex_-11_fc.pdf
According to my trials the different 3M spay adhesives don't work very well for CLD by themself but to attach a viscoelastic sheet.
I think PU adhesives are good candidates but several PU construction adhesives I used cure quite hard except the ones for floorboards but they are normally used in this application with nails so adhesive strength is not so good by themselves. The Loctite PUs I used (U-05 FL and U-09 FL) are according to Henkel viscoelastic but it would be nice to find a more accessible solution.
 
I was building small panels for my drivers using sheets of aluminum (4mm) and Richlite (8mm). The adhesive I used was 2 component urethane (Loctite UK U-05FL) which supposed to have some viscoelastic properties but it comes only in 50ml cartridges. These panels are quite dead, more than a similar panels with Richlite and baltic birch plywood and both versions obviously much less resonant than plywood (including bamboo) alone.
Searching for adhesives for CLD I found often recommendations for green glue (tried it myself) or Swedac. These are water based products and work with drywall or wood derived panels but never cure with nonporous materials. Other recommendations are caulks like for instance Weicon flex 310 PU but thesis cure through air exposure and will cure only maximum 25mm in nonporous materials.
VHB tape would work but gets expensive for larger surfaces and I would prefer adhesives for assemblage. Also I like to avoid adhesives which are available only in large containers like Decidamp DC30.
Look for Shore hardness scale, adhesives should have a shore number in their datasheet so you can quickly evaluate if it is suitable or not.

I think what you want for CLD is shore A 30-40 or something like that. Geddes used Innovative polymers product IE40, which seems to be have shore A 37 +/-5
IE40A-data.png


shore-scale.png
 
Last edited:
  • Thank You
Reactions: 1 user
In my last build I used nail sealing strip. "Nail sealing tape PROFI is a double-sided adhesive butyl nail sealing tape with protruding silicone paper for sealing nail, tacker and screw joints. The sealing tape can be glued directly over the rafters onto the pitched roof membrane (underlayment membrane, sarking membrane or formwork membrane) or at the bottom onto the counter batten. Thanks to its aggressive adhesive strength, the tape also adheres to rough-sawn wood. The nail sealing tape PROFI is cold-welding and offers the highest level of safety and reliable protection against moisture penetrating into the insulation due to its cold flow." https://www.heimwerker-direkt.de/alfa-nageldichtband-profi-50-mm-x-20-m

It really sticks agressively to everything, especially human skin.
 
for Weicon see: https://assets.weicon.de/#/asset/306597
Sikaflex 11Fc is moisture cured so needs air access to cure https://usa.sika.com/content/dam/dms/us01/6/sikaflex_-11_fc.pdf
According to my trials the different 3M spay adhesives don't work very well for CLD by themself but to attach a viscoelastic sheet.
I think PU adhesives are good candidates but several PU construction adhesives I used cure quite hard except the ones for floorboards but they are normally used in this application with nails so adhesive strength is not so good by themselves. The Loctite PUs I used (U-05 FL and U-09 FL) are according to Henkel viscoelastic but it would be nice to find a more accessible solution.

That's the wrong stuff. You want this: https://assets.weicon.de/#/asset/306598

I still don't where you get the idea that it will only cure an 1" in.
 
Glad to see a thread where this is being considered. So many out there think that glue is glue, oil is oil, air is air, etc. Yes, there is a best product for a specific application.
Green Glue did work for me pretty well in a construction application, but I have wondered if it was usable and successful for other applications as well.
 
I just found out that Innovative Polymers was bought by Rampf and that IE40-A is not anymore available. I try to find out if any of their PU would work.
One issue which not really directly related to Shore hardness is whether a flexible polymer is elastic (acts like a spring and returns all vibrational energy) or viscoeleastic (absorbs vibrational energy, also described as low rebound) and that is data is very difficult to find.