sac

Just finished coating the wheel wells & trunk lid of my Miata with Spectrum liquid from Second Skin Audio. First time I have used it.

The Miata is very noisy, and a lot of the tire & road noise comes through the wells & floor. So I figured I would try to do something about it (dampening inside the cabin is coming soon).

I'm very impressed. 2 gallons, brushed on, gave me 4 VERY thick coats on all 4 wells, the trunk lid (did only the cutouts), AND the insides of the front quarter panels. Also put some on the plastic covers inside the wells -- and yes it bonded fine.

Seemed to take at least a couple of hours to dry (remember, were talking thick coats in an underground garage, so no wind, no sun, no heat - 65 degrees tops). I was able to put a couple of coats on the trunk lid each evening (one at the beginning of the evening, one at the end), and one coat on each wheel well. Because I was putting on such thick coats, I waited a day between coats, but overnight would have been fine. And the trunk had to be closed at night, so that slowed the curing time there.

I noticed that Spectrum really sticks well to itself. So (using a brush) the first coat was not too thick, but each coat thereafter could be made really thick.

Results: My trunk lid & the front fenders seem much more substantial now. I actually walked around the garage tapping on a few cars (carefully, only with my knuckles!) to compare the sounds. Everything else (including my doors & hood, which haven't yet been done) sounded like tinfoil in comparison. They're next on the agenda.

And BTW, Anthony (the owner, a good guy to do business with) confirmed that Spectrum can be used under the hood -- the heat is not a problem.

Haven't taken the car out yet. Will do so soon, and I'll post observations then. Keep in mind that I have yet to dampen the cabin, doors, trunk. May use some Spectrum for these, but more likely mat, as I can't afford to have the car in pieces for several days.

Clean up was easy. Kept a pail of soapy water handy, and the brushes (and my hands) cleaned up with water. Just like latex paint. No problems.

Would I use it again? Yes -- I've already ordered more. As for its effects, I should have more to say in a week or so. But I suspect that the true benfits will occur once the whole vehicle has been done. And that is a month or so away.

xxPunk0Ramaxx

well, this is not the first positive review i've heard about the liquid deadener. most people have had great experiences with both the liquid deadener and the mat.

my question is how much heavier are the parts, particularly if you put on as thick coats as it sounds like.

JohnVroom

To adequately dampen sheet metal you have to apply a similar amount of mass to the sheet metal itself. This is an ugly but true principle you almost double the weight of the sheet metal.

What you are doing is attenuating the amplitude of the vibrations and shifting the resonant frequency of the panel. If you were to apply a product that hardens or has a high stiffness to weight ratio (adding fiberglass for instance) then the resonance frequency shifts upwards and hopefully out of the area of concern, adding the soft dampening material should lower the resonant freq and hopefully away from the resonance applied to the panel (road noise).

I am not sure there is a lot of weight savings over any other product but if you are coating the entire car with 40 mils... I would look for manufacturer proof that their product works as well as the competitor and weighs less. I would also treat it as an unsubstantiated claim since there are no formalized testing (ASTM) or performance parameters for comparison (the only real parameter that every manufacturer of dampening materials use is price).

JohnVroom

You are correct and I tried to say that too but tripped over my wording. There is ASTM testing but the manufacturers do not always post them or the same ones... From experience, ASTM testing can cost big bucks and these are small companies, so many probably don’t do it

The solid products do not loose weight after application, the liquid products loose water or VOC's as they dry. The only question is how much evaporated?

Also how 'finished' is the outer coat? If you put it under the hood will it chip/ flake off over time? How easy is it to damage?

Surface preparation is VERY important for ALL types of dampeners so the stuff will stick.

sac

Not quite Ettore -- remember that the full pail contains water as well as the lime (adds weight) and polymer. Once the product dries the water is gone. Approx total weight (dry) is 4kg/gal. I suspect that all of the deadening (mat + liquid + closed cell foam) will add maybe 60lb to the weight of the car. Wish I could avoid this but the soon-to-be-installed turbochrger should help that little issue...

As for the actual sonic benefit -- this really is an experiment. Logic suggests that all of the effort will pay off. I suspect that the mat/foam for the doors and interior cabin will provide the most benefit. The rest is just to see what happens. Like I said I'll know more this week once I actually drive it again.

And ambient noise at freeway speeds in a Miata is 94+dB. So I could use all the deadening/insulation I can get.

Rick McCallum of Raam Audio has provided a good tutorial for deadening: http://forum.elitecaraudio.com/showt...hreadid=106016

And I'll be getting my first shipment of Raammat & Ensolite foam in the next couple of weeks. Was thinking of using B-Quiet but it costs 50% more. Should have it installed by July 1. Then I'll have a better able to comment on the value of the whole deadening project.

[ May 30, 2005, 12:10 PM: Message edited by: sac ]

sac

John it looks only as good as you make it. Just like any paint job. Spraying gives the cleanest finish. And I was more concerned with layering on a thick coat rather than making it pretty (after all, who ever sees it?) But with some care you can brush or roll on a very clean coat.

The stuff feels like rubber. Pliable but not really soft. So it can be chipped off (with effort). But I don't expect that it will come off on its own (I'll know more after driving for a season and observing any stone chip effects in the wheel wells). So far the under-hood and under-floor pan applications are going smoothly (will finish this week).

And yes surface prep is key. I used plenty of diluted degreaser to prep the surfaces. But it didn't take long to do.

[ May 30, 2005, 12:12 PM: Message edited by: sac ]