Green glue sub

[wkrbee]

Would regular old silicon RTV work just as good as Green Glue? Seems it would work as long as you put on a thick bead

[norton]

you would think it would... but apparently nothing comes close to green glue in tests.

i was just involved in a project working for the lab that tests green glue and nothing else they've tried works. i asked a pile of questions, and they tried and tested pretty much everything out there. traditional, non-traditional you name it.

we got to use a bunch of it... and it's a little messy, but pretty cheap when you think of the amount of materials it takes to get the same results, and that you don't have to give up so much floor space to crazy thick walls.

[Rod Gervais]

Would regular old silicon RTV work just as good as Green Glue? Seems it would work as long as you put on a thick bead

Wrkbee,

they work in a totally different manner.

Silicone RTV would actually glue to pieces together - creating (for all intent and purpose) a single piece of board.

This is not how green glue works.

Green Glue does NOT actually glue the pieces together - rather it creates a constrained layer damping system (CLD).

In a constrained layer damping system (CLD), a damping material is sandwiched between two other (usually stiff/rigid) materials. Damping occurs
when the viscoelastic center of the ?sandwich? is sheared.

When bent, shear forces pull and stretch on the damping material.
Energy is lost when the damping material is sheared. The vibration energy
is not isolated, it?s destroyed, and converted to heat at a rate defined by the
efficiency of the damping material.

This is totally different than using an adhesive to glue multiple pieces
of material together.

When two pieces of drywall (for example) are joined together (through the use of conventional construction adhesives) they bond, forming (essentially) one thicker piece of material. The effective isolation created from this type of assembly is less than the sum of the individual sheet themselves.

Thus, by gluing sheets together you decrease (rather than increase)isolation.

However - with Green Glue, the bonding actions that take place with
conventional adhesives never occur, and the isolation is greater than the sum of the two sheets themselves.

I hope this helped,

Sincerely,

Rod

[wkrbee]

I was thinking of using the RTV just like you would use the green glue-a thick bead spread on the surfaces to make a damping layer just as you described.

[Rod Gervais]

I was thinking of using the RTV just like you would use the green glue-a thick bead spread on the surfaces to make a damping layer just as you described.

The problem is that it would not make a damping layer - it cures - it sets up - and it adheres - when all is said and done - it would glue the pieces together.

I understand what you're thinking - but (as I keep telling you) you cannot make it from A to B with this product.

In fact - I do not know of any product that does what green glue does except green glue.

If you want the bang that comes with green glue - then make the investment - if not - then just buy enough mass to make up the difference.

Sincerely,

Rod

[wkrbee]

Must be some magic stuff. Went to the Green Glue site and saw all kinds of third party data-but nothing comparing it to RTV,(not to beat dead horse Rod).Now I have to convince my wife that spending $180 a case,(need 4-5 cases),is cost effective.Last time i bought something,(Hammond A-100),I had to buy her a new sofa.

[Rod Gervais]

Must be some magic stuff. Went to the Green Glue site and saw all kinds of third party data-but nothing comparing it to RTV,(not to beat dead horse Rod).Now I have to convince my wife that spending $180 a case,(need 4-5 cases),is cost effective.Last time i bought something,(Hammond A-100),I had to buy her a new sofa.

bee,

that's because they wouldn't bother wasting the money to provide tests for a product that isn't made for the purppose, that they knew would never compare. These tests are very VERY expensive - so why compare it to an adhesive when you know what the results will already be?

Their comparisons are related to products being sold for the purpose of performing the same task as their product - which makes all the sense in the world.

As far as convincing the wife goes - just let her know that in the long run - it will be a heck of a lot cheaper than using the wrong product in the first place.

Ripping things apart to fix them is always more costly than doing it right the first time. And gluing sheets together lowers your isolation - so tis not a good idea.

BTW - I have more than a few dollars in construction under my belt - I wouldn't send you in the worng direction.

Sincerely,

Rod

[wkrbee]

Thanks for the info Rod