sound deadening

Using peel and seal in a car is like smoking cigarettes - some people don't have any problems, some die a horrible death A little over the top perhaps, but several things argue strongly AGAINST using it, despite individuals reporting success.First, peel and seal  uses asphalt for its mass/adhesive layer. Asphalt is not viscoelastic. Butyl is. Viscoelastic damping is important.Asphalt is much less consistent, batch to batch than is butyl. Sometimes it is sticky enough, sometimes it isn't. No matter how strong the initial adhesive bond, asphalt begins deteriorating as soon as it is manufactured. Rubber is added to the asphalt to increase the asphalt's heat tolerance. The rubber compounds degrade at temperatures much lower than those required to melt the product when it is fresh. Heat tolerance declines with time. At the same time, asphalt is flexible because of the VOCs it contains. These compounds aren't stable and outgas from the mat over time. To add insult to injury, the gasses are toxic. People complain about the smell, but that's ujust letting you know you are getting your daily dose of VOCs.Basically when you apply asphalt inside a car, you are starting a race to see whether it will melt or become solid. It will certainly do one or the other. So you have a marginally effective sound deadener that may damage your vehicle and harm your health. Asphalt failure can occur up to 4 or 5 years after installation.So what do you do if money is tight and you need to deaden some panels? Spend your budget on a good quality butyl mat with an aluminum foil constraining layer, just buy less square feet than you planned on and spread it out over your project. The odds are very good that the results will be better and you won't risk any of the downside problems..................................................................................................................................................................................          I copied and pasted this from "Rudeboy".....Sound deadening showdown