I totally agree with this. If you look at the plots on any chart for the DLF of a damping material (ASTM-E756) you will see a drop in performance starting at about 90*F and slowly dropping off as the temp goes up. Optimal performance seems to be centered right around room temperature (70*F).
One of the primary surfaces that is of benefit for CLD products are the outer door skins of an automobile. Direct sunlight is obviously going to play a major roll in the performance, especially with a parked vehicle. But, if you garage your vehicle or park it in a ramp...away from the sun, I don't think it's a MAJOR consideration and therefore I agree that there are other things to worry about IF the skin of the door reached 200*F...primarily burning your hand when you touched it. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif Also, the movement of air across the skins will undoubtedly cool the surface as you drive down the road.
Testing above 200°F has nothing to do with damping performance. As you may recall, at the time of last publication, many manufacturers were making deceptive claims about the composition of their adhesives. Almost none admitted to being asphalt. testing at 200°F and above resolves that question very quickly. In addition, manufacturers using butyl where making high temperature claims that I wanted to verify.
Since doing those tests, industry scientists have been kind enough to explain that they routinely test at temperatures that are significantly higher than the products will ever see. With polymers like these, exposure to higher than normal temperatures models lower temperatures for much longer times so it is a way to do accelerated aging tests.
I think Don just did the best he could here, but I agree it's not all that valid. It seems to me that adding weight would impose an elongation stress to the foil. But CLD products are known to work better for naturally stiffer, thicker substrates that undergo shear stress. Seems to me that hanging weights would be more valid for a free layer/extensional damper which is a better product of choice for a substrate undergoing extension/compression stress.
I think those that have been convinced or are under the illusion that heavier "deadener" is better....or feel the need to go overkill by multi-layering CLD products, might be the ones hanging weights from their deadener. //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif
Hanging weights from strips of deadener also turns out to be a sightly cruder version of a standardized test done by manufacturers. It is not intended to mimic real world conditions but instead gives you a way to compare relative adhesive bond strengths. This has proven very valuable in trying to get to the bottom of adhesive failures like those some people have experienced with some of the new butyl versions of eDead. In that case, weak adhesion combined with a Mylar facing with a strong inherent curl has caused the product to peel itself off of the substrate.
A secondary characteristic of butyl is that it has a relatively weak initial bond that increases in strength with time. Generally speaking, the higher the quality of the butyl, the greater the difference between immediate and delayed measurements. All of my recent testing has been done immediately and then after 96 hours.
In almost every case, the people who have insisted on taking the heat and adhesion tests literally have been more interested in discrediting the results than in getting to the truth. I originally had tests that showed the results of soaking samples in acetone and in mineral spirits. Both showed interesting features of the products, but I got really tired of explaining that these tests were not designed to show what would happen if you soaked your car in either solvent so I just eliminated them.
I'd love to see some DLF figures on RAAMmat and DP. It seems that the testing is too expensive?? Not sure about Ant, but I know Rick a)doesn't like them b)probably doesn't want to afford them?? Again, can't speak for the guy....just going by what he's said in the past.
My personal opinion is that if you want to say you are the best, you need to lay down some objective figures rather than piggy backing off others in the industry and undercutting them on price. //content.invisioncic.com/y282845/emoticons/wink.gif.608e3ea05f1a9f98611af0861652f8fb.gif
I investigated having Oberst bar testing done to develop ALF numbers for each product. At $600 per sample, I wasn't going to pay for it myself, but considered offering myself as a middleman. The manufacturers could pay to have their product tested and the results could be sent directly to me for publication. After talking to a lab that not only does this testing but also develops vibration damping solutions for aerospace, I concluded that it wasn't worth the effort. As it was explained to me, ALF differences really only have meaning when you are testing solutions to the problems of a specific part. In the after market sound deadening market where people just slap this stuff on, the subtle differences between aluminum foil/butyl products that testing would reveal are all but meaningless.
One of the reasons that ALF testing hasn't been embraced by most manufacturers for marketing purposes is that there is a lot of bogus information out there. Some of the published numbers were achieved by tweaking the tests and others were simply made up. This was first explained to me by Doug, the owner of Cascade, so I'm not suggesting that their numbers are wrong, just that you can't learn much by comparing results between companies.
When it comes to comparing constrained layer viscoelastic dampers like those being discussed the key factors are thickness of foil and quality of adhesive. Beyond that, they need to be pliable enough for our purposes. The gold standard in general purpose products is probably 3M's product that has a 15 mil foil and 5 mil adhesive, but that's just in terms of pure CLVED performance. In our application it gets more complicated.
There are three basic mechanisms we have to deal with panel resonance. The first is viscoelastic damping already mentioned. These products can also stiffen the panel which raises its resonant frequency and adding mass which lowers it. To some extent, these mechanisms are going to offset each other, but that misses another important consequence of adding them to the panel - both stiffening and mass loading increase the energy required to excite the panel in the first place. Even products like Peel & Seal will be better than nothing - if they don't fall off or melt, which bring us back to the first two points above.
Debating which is better, Damplifier or V-Max, is coming close to arguing about how many angels can dance the head of a pin. Both are at the very top of the quality scale. I doubt that anybody will be able to tell the difference in actual use. Mass actually does matter, so Damplifier and Damplifier Pro have an edge there. Damplifier Pro has thicker foil. V-Max has an attractive anodized surface and the ceramic spheres in the adhesive may or may not enhance performance. Who knows? More to the point, who cares? At this level, both are going to do a very good job. Dynamat Xtreme isn't that far behind either. If you have a butyl adhesive with decent bond strength and a reasonably thick foil, how you use the product is going to be at least as important as these details. Both companies can be proud of themselves. Arguing about who is the true innovator is like arguing about whether Microsoft or Apple invented the GUI - neither did, Apple took the idea from Xerox PARC and Microsoft followed Apple. In the same way, CLVED's have been in use, in other industries, before Cascade or Second Skin even existed. Silly argument.
