Anyone have Whispermat gluing problems?

[JonP]

Hey all... I posted this to the PE site as well.. also posting here since I KNOW there's several Whispermat fans about.

So, I've been working on a pair of speakers, and have them nearly done. Got some of the vaunted Whispermat, and used 3M 77 spray adhesive.

Well, some pieces fell off under their own weight later.. and the next day, they all were barely attached. At first I thought it a combination of not enough spray on all surfaces, and that the dampening mat surface (I bought both the foam-dampening-foam type as well as the foam-dampening) seems slightly oily. Figured I should have wiped it with something to degrease it first.

But after 24 hours, it seems ALL the adhesive can be wiped off, and is just a gummy mess, rather than a glue. It's as if some chemical interaction has happened. Anyone run into this? Anyone using Whispemat have a good glueing suggestion? The foam-barrier-foam stuff is tightly glued, you will tear foam before the joint lets go, so its not like I got a bad can of spray cement... it's completely cured.

I've read Zaph's writeup on using Whispermat, and suggests 3M 90 spray works great. I didn't think that the somewhat cheaper stuff would do so much worse, but I guess there's some compatibility problem.

Well, there's always thumbtacks and the heavy duty stapler... ;-)

[tf1216]

I ran into the same problem myself. i do not recall which 3M adhesive spray I used but I also got the idea of using Whispermat from John's website.

Suggestions I can offer are try using clamps with wood blocks to press and hold the Whispermat in place. Also, carefully read the directions on how to optimize the adhesive spray. I had slightly better results after spraying the wood and then waiting a bit to press on the Whispermat.

Since trying the Whispermat, I bought the dampening material from PE. What a difference sticking foam to mdf when it comes with a sticky side. ( :

[Dennis H]

3M Spray 77 and 90 are contact cement so you'll get the best results spraying both surfaces and letting them dry before pressing them together. Multiple coats may be necessary if the foam sucks up the first one. That said, I've never used Whispermat so I can't comment about that.

[JonW]

I haven't used Whispermat yet but am planning to with my ongoing project. I was wondering if hot glue might work well?

[JonP]

I did read the can, and followed the suggestion to spray both surfaces, and put together within a few minutes for strongest bond. I sprayed the mats, then sprayed the wood surface, then started putting things together. The 77 can implied that the strongest bond was made when you put them both together before they dry. I probably had 4-8 minutes from spraying the pads to putting the last in place.

I did get a reply on PE, that mentioned the 77 isn't as reccomended for plastic surfaces... and 90 is, so it seems likeler that I'm getting an interaction. And, the foam to wood pads did work extremely well.

I'll have to see what might clean off the 77 remains, and not melt the damping layer in the Whispermat. Any suggestions?

[kingpin]

Goof off, or Goo gone.
These are adhesive removers btw. :B

[Brandon B]

I am using something that may or may not be whispermat (bought from Sounddown acoustic products who makes the same or similar stuff). I used a big industrial hot glue gun to adhere it to the interior of my speakers, and it is NOT coming off no way no how. So that is definitely option.

BB

[JonW]

I am using something that may or may not be whispermat (bought from Sounddown acoustic products who makes the same or similar stuff). I used a big industrial hot glue gun to adhere it to the interior of my speakers, and it is NOT coming off no way no how. So that is definitely option.

BB

Good to know. I'm thinking of just using a glue gun to put a dab of glue in each corner and maybe one in the center. It sounds easier, cheaper, and less messy than the Super 90 spray adhesive. There must be a down side.

[bob barkto]

The down side is you'll lose coupling of the dampening surface to the cabinet wall when applying the "damped-foam" product.
It will be ineffective as a cabinet wall dampener when it's largely floating in free air or just laying on the surface. Nearly complete adhesion is required.

The "foam-damped-foam" won't suffer.

[JonW]

Yeah, I was wondering about exactly that. But then I was thinking about what was mentioned in the Dickason book regarding roofing felt for damping vibrations. For that he said just put a staple in each corner and one in the center. So if I did that with the foam and dabs of glue... But I don't know that it's the same thing. Nor do I know that the felt things works well either.

[bob barkto]

If Dickason is recomending that as a dampening solution I'd think he's incorrect. It might provide some absorption when just loosely attached. But it won't damp panel vibration or resonance when used that way.

Inside a loudspeaker enclosure, whatever material is used, it needs to be tightly coupled to the panel to be effective at damping the panel.

If you have a small piece of sheet metal you can experiment and hear the relative effectiveness of a solid bond and a loose one compared to the plain metal.

Don't waste your expensive Whispermat, use some vinyl floor tiles or roofing felt or similar material. You should be able to hear the difference, or lack of.

[Dennis H]

Whispermat and the PE sonic barrier stuff don't have the 'cabinet damping' mass layer of Black Hole 5 so how you glue it on doesn't really matter as long as it's stuck enough to stay in place. The PE stuff already has a stick-on glue on it so you don't need to sweat how to attach it.

[bob barkto]

Hmmm. May be a semantic argument but according to Whispermat's description it does. The WM1 has a "barrier layer" on one side and foam the other.

Some of the PE Sonic Barrier does too, but it's sandwiched between foam so strictly speaking it isn't a panel dampener but more of an isolation barrier/decoupler.

[Brandon B]

No, the whispermat as well as whatever I have does not have the 5 layers of BH5, it is missing the densest layer which goes against the cabinet. I bought the PE stuff that is similar with PSA on it and put that on the inside of my cabinets first, then hot glued the whispermat to that pretty thoroughly. 1.5" MDF cabinets with with some bracing and that stuff, ended up pretty dmn dead.

When in use (these are the Orca Design Aria 5A with the Accuton tweeter and 2 focal 5" midwoofs) and up reasonably loud, I can feel the surface the speakers are sitting on resonating with the bass frequencies pretty significantly, but the cabinet sides are dead quiet.

BB

[JonP]

OK, to clear up things a bit on Whispermat, there is a version (WM1) that has a 1/2" foam layer and a massy plastic or rubbery layer on one surface. You glue the rubbery damping layer to the box. There, I agree, total bonding will have the best effect. The other version (WM2) has 1/2" of foam, the same massy layer, but with another 1" of foam above. The massy layer is suspended between. You glue the 1/2" foam layer down.

(edit to clarify the WM2 version of the stuff)

I have used the heavy roofing felt/tar paper approach, and in knuckerapping around, it did seem to use many staples was slightly worse than one every 3-4". Kinda counterintuitive, (and not totally scientific of a test, as well) but it might show that several loose layers perhaps is more absorbant and dissipative than a single heavier one, due to the layers moving independantly.

I noticed that a lot of what I was hearing was higher frequency ringing, rather than lower frequency boominess... (box was pretty well braced) I'd guess that a more solid layer might help with the LF, and the "fluffier" layer might do better with the HF box resonances. With the Whispermat, you probably get the heavy layer lowering the LF, and the foam soaking some HF.

Still wish I had an accelerometer to see how much of what I have and what's changing...

[Paul Ebert]

Where can I buy whispermat?

Thanks.

[Hank]

Try our #74 foam adhesive: http://solutions.3m.com/wps/portal/3...izePageHandler

[JonP]

OK... I'm reporting back.

Did a bit of editing on my last post, it still was a bit confusing about the WM types.

I talked to a Rockler store guy who's the finishing expert... and he suggested Lacquer Thinner as a solvent. He had had some experience with the 3M spray adhesives. We tried some on the gummy result, and it does dissolve the adhesive remains without dissolving the Whispermat mass layer. (at least very fast) We tried some on the foam to see if it would damage that. The foam dosen't seem to dissolve either, but it swells about 25% and feels softer than before, so something's going on there. Just avoid getting any solvent on the foam.

So with a lot of wiping, I was able to clean my Whispermat pads, and the inside of my boxes. I bought some 3M 90, and successfully glued them down. Looks like you need to have both surfaces well covered for this one to work well.

Sounds like we have a 3M employee here! Hi Hank... Is it normal for 90 to come out in threads rather than a fine spray? More like a drizzler than a sprayer, but perhaps that's normal. I didn't see the #74 at my local HD, but did see a 60 (?) that was for vinyl and rubber products. I probably should get in touch with the Whispermat folks to find out, maybe we can come up with a few options for a good bond.

(edit on this one for the right spray I used)

[---k---]

Would regular contact cement not work well also? Maybe not as easy to get good coverage inside a box as a spray is though?

[Hank]

Hi Jon - yes I work at 3M - Sourcing Manager for Visual Systems (overhead and electronic projectors). I've used a can of 90 and it does come out in more of a stream than mist. It's usually used for fairly large areas and it's fairly thick, so a fine mist would take longer and some would be lost in the air. As I recall I used it on trunk liner. Retail stores carry 77 and 90 more than 74. If I knew exactly what the Whispermat material was, I could get a chemist's recommendation.