Laminating plywood to MDF.....

[gbegland]

What is my best option, regular old wood glue or something like green glue? Anyone out there tried this green glue stuff?

Thanks

Greg

[Hdale85]

I'd say scuff up the MDF with some sand paper and use wood glue. Should work fine.

[gbegland]

Thanks Dougie

I've done the wood glue route before and it's fine, but I am curious if some other adhesives might offer a type of sonic benefit as well as hold the layers together. Any other thoughts guys?

Greg

[JJones]

I've done the wood glue route before and it's fine, but I am curious if some other adhesives might offer a type of sonic benefit as well as hold the layers together. Any other thoughts guys?

Greg

Yes.

It would be something that's not bouncy and springy like silicone rubber, and something that doesn't dry hard like wood glue.

Constrained layer damping offers good benefit to speaker enclosure walls. One type is this semi-viscous loaded double sided self adhesive vinyl sheet that comes in rolls. To use that, what you do is coat the insides of both the sheets of wood with contact cement, let it dry, then carefully cover one glued board with sheets of the damping material, then, press the other sheet (glue side down, of course) onto that. The contact cement forms a surface that the adhesive strips can really stick to firmly.

[Ray Collins]

JJones,
Can you provide a brand name or source for this particular type of vinyl?

Ray

[Dennis H]

In an ancient thread, and almost by accident, Thomas found that plain old rubber contact cement gave a deader panel than wood glue.

[Ray Collins]

Do you think it is preferable to a thin layer of silicon sealant?

[JJones]

JJones,
Can you provide a brand name or source for this particular type of vinyl?

Ray

I was trying to find some info online, haven't yet. I've got a roll of the stuff, but it's not labeled. On the outside is a plastic coated white release paper and on the inside is thin a translucent plastic release sheet. The material itself seems something like a cross half-way between vinyl and tar/bitumen and it's maybe a little over 1 mm thick (about 1/16th inch, perhaps).

I'll keep looking to see if I can find a source...

Do you think it [rubber cement] is preferable to a thin layer of silicon sealant?

I would think so. Silicon rubber has generally been a fairly poor material for acoustic isolation in any applications that I've tried it. It seems to be too "bouncy" to "absorb" (convert to heat through internal friction) significant sound energy. Though, I guess it is decent at isolating shock from impact, such as bushings for HD shock mounts...

EDIT: Something like this: http://www.bestmaterials.com/detail.aspx?ID=14791 is good for damping, though, not the same as the material I mentioned earlier (for one thing, it's not sticky on both sides). I would also suggest digging around to find a cheaper price, that price looks REALLY high to me.

[Hank]

Here's the Parts Express vinyl-based product:

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=268-035

I've been wanting to do a constrained layer thing with it between either two sheets of MDF or MDF/Baltic Birch plywood. One side is coated with a very strong pressure sensitive adhesive, so you'd only have to do apply contact cement to one side.
I'm intrigued by the rubber cement idea.

[ThomasW]

What is my best option, regular old wood glue or something like green glue? Anyone out there tried this green glue stuff?

Haven't tried green glue only used Titebond and as Dennis noted Contact Cement.

In instances of larger laminated panels they all dried with a slight bow. The only time I successfully eliminated the bow was when there was a plywood core and MDF was laminated to both sides of that core.

[Amphiprion]

I second/third/whatever the recommendation for plain old contact cement if you are going to do a lamination.

I've seen birch plywood bend noticeably when applying polyurethane to 16" x 8' long panels meant for shelving, so I would trust Thomas's experience with the sandwich technique.

[Ray Collins]

Thomas,
Were the results worth the effort?

Ray