Green glue? A scam?

I've been building my new studio for a while and I've been reading the acoustical design forums pretty regularly. Green Glue is a brand of "glue" that is used between layers of drywall to increase the STC.. It claims to help considerably more than anything else used between the layers of drywall. It's also SUPER expensive.

I have always been a little wary of these claims, but I was reading their website and came across their MSDS sheet.

Ingredients: Latex polymer, water.

That's it. It's a waterbased latex paint!

???? They want something like 180$ per case, which is 12 tubes.. 15$ a tube? You are supposed to use 3 tubes per 4x8' sheet of drywall...

Has anyone used this?

I haven't used the stuff, but I've been in construction for a long time.

It's glue, not rocket science.

I went to the local home building supply store and rummaged through their caulk/glue isle. I found a panel adhesive whose ingredients are latex copolymer and water... 40$ for 3.5 gallons..

It's a very expensive and scientific process to remove the "co" from the polymer.

Not to pump up the $180 cost, but most manufactures don't have to indicate anything that is a trade secret.... But I took a look at the MSDS, there they do have to.

Buying Auralex TubeTak I peeled away the label and it was a hard wood floor adhesive that is not available to the general public. $8 TubeTak, or $2.75 other stuff.

I do understand why you use it ( it didn't eat into the foam) so it was easy to remove off the walls. I ran out of the case of the stuff I bought so I hung a few pieces with Liquid nails. When I removed that I tossed the foam and had to restore the drywall, texture and repaint.

i specced green glue on a soundproofing job that i consulted on. it did work very well and it was easy to use. whether or not some other brand of adhesive would have also worked equally well, i don't know.

"latex polymer" is a pretty broad class of substances.

ed

I'm no expert on acoustics, but I know a bit about latex and polymer chemistry.

Saying "latex" is rather like saying "wood" or "metal".

You can engineer a latex to have a wide range of mechanical properties. I don't know anything about this product specifically, but it is conceivable to me that it might be different than a run of the mill construction adhesive like liquid nails. Off the top of my head, I can imagine a low density latex adhesive (like a foam) could decouple the drywall panels better than a stiff adhesive. It seems reasonable that a sheet of drywall, glued to a sheet of neoprene, glued to a sheet of drywall would have a better STC at certain frequencies than two sheets of drywall glued together (or a single sheet of drywall at twice the thickness). The former construction is what this product might aim to approach.

-Chris

so would it also be safe to assume that loosely screwing the drywall together would be a solution as well then?

I'd be concerned about rattling at certain frequencies then

I'm at a loss as to how adhesive between layers of drywall can have any more than an extremely minimal impact...

Visit www.johnlsayers.com and hit up the forums if you really want to get to the bottom of this green glue issue.

Personally, i think it's a complete waste of effort and money.

EDIT: SEE BELOW

OK, so i decided to do a little researching for you, as your pique my curiosity. From what i can gather, GG makes a difference, and there is not cheaper method or product that even comes close to matching it's performance.

This info comes from Rod Gervais who is a very well respected studio designed.

However; we have gone a long ass time with the double layer drywall - rigid insulation - double layer drywall method with no real isolation problems...so that begs the question, is GG really "worth" the expense.

I looked at the test data for the product, and was a little confused by it as they used r13 insulation instead of the standard rigid insulation that one would normally use for audio isolation purposes. Makes me really confused when trying to interpret all the numbers and hubble-dee-hoo i've read about GG.

I'll keep seeing what i can find out for you.

[quote author="Svart"]You are supposed to use 3 tubes per 4x8' sheet of drywall...[/quote]

I read 2 tubes per sheet, and i also read that even doing half that makes a considerable difference.

In my last studio build I used Black Bitumen, no sure the correct name for it, but it's typically used for sealing roof and gutter materials. It is real cheap, seems to stay in a pliable state, well at least 1 year on it is still pliable. I've used it between sheet floor layers and drywall layers to glue them together. Also used it to plug up joins and holes. Worth checking out as I think it is the cheapest adhesive/sealant available.

Michael

unless Green Glue cures like a rubbery foam I just don't see how it could really help..

that's exactly what it does, and it's designed to work exactly opposite of most construction adhesives. Construction adhesive has an extremely high shear strength, GG has a very low shear strength.

The more I read about it, and the more i see very respected studio builders using it, the more I am believing in it's ability.

However, we've gone this long in the recording world without it.

Sidenote, does this link work for anyone?

http://www.johnlsayers.com/phpBB2/index.php

a lot of studios use Monster cable because it is supposed to work better too.. We all know that is a lie.

i was also thinking of hanging thick slabs of drywall on the backs of the open areas between the studs to dampen resonation. If you tap on the drywall between the studs, it rings. If you hang something heavy between the studs on the back of the drywall, it thuds.

Anyone try this?

Thes folks have some products that do certain tunable damping tricks, including incorporating internal masses and springs:

http://www.msr-inc.com/studio/studio.html

yes quite like that. I was thinking more like a harmonic damper on a car, something heavy coupled by some form of rubber or foam.

I might have to try it..

What about that heavy rubber matting that people seem to use, it's about
1.5cm thick and in sheets of 150cm x 300cm
It seems to pop up in the "Sound-on-Sound" magazine insulation series.

MM