chevysurfer

I do commercial waterproofing and caulking for a living I work with these materials everyday. I have spent the last 2yrs working on a military base doing large scale jobs. The core of engineers are very **** and spare no expense so the materials and procedures had to be top notch. That being said I have learned some things. First any time you by material that serves multiple purposes, the trendiest one will be most expensive. I mean "flashing", "perma-barrier", "peel and stick", are construction materials bought in bulk used in bulk by the thousands of feet there for are cheaper. Dynamat which is extremely popular still has a smaller market there for is more expensive. The asphalt based peel n stick is that way for a reason, there is a expensive primer that you are suppose to apply to the concrete foundation first, it activates that butyle asphalt chemically when that happens it melts, filling the little voids on the surface of the concrete, permanetly adhering to the concrete(letting of way worse of a asphalt smell than you smell on it normaly). Both styles of peel in stick buytle or asphalt will degrade if expose to uv rays for to long. asphalt base will tend to gummy if extremely hot, but so does the other kind. My opinion is why are audio guys paying for the aluminum backing on dynamat its not on your roof, and the aluminum is to deflect heat to keep the rubber from getting soft and melting. Its weather proofing material and in that it will keep in heat during the winter and cold during the summer(by sealing passage ways blocking air and moisture) the aluminum in a car is pointless. In a vehicle it works by insulating thin metal that would transfer cold or heat thru it. But since we put it on the inside and cover it with carpet the aluminum is useless. Alright last point dynamat is the other brand, go get some GRACE, HENRY,CARLISLE and a dozen other construction brands whatevers cheaper its all the same. Also the primer we use is about a 150 bucks a bucket you could do 20 cars with that. What I would suggest and I have used it is get a bottle of loctite spray adhesive, cheaper and as good as 3m spray, spray back side of material and metal wait till tacky 1 to 3 minutes and apply press out real hard. In curvatures cut slits, dont let it fold or wrinkle. Dont lay over voids in metal cut slits, if not that will later cause problems for lifting. making it look real good(by using big peices with no breaks) is not as important as just making sure it has contact to metal every where thats whats important. But stay away from real small peice not enough surface contact to stick. Im not a proffesional car audio installer, but I am a proffesional waterproofer. I can bet I lay out in a month what installers might lay out in 1 to 3 years. A cars about 150 sq ft and takes a day, I lay twice that by lunch. All jokes aside I understand cars are labor intensive. I did mine and it sucked and I took my time. Much props to installers. Final note when its all done know one can see it do the installing of it right and it will do what its designed to do. The car dont care what brand names printed on it so save some cash and get the real stuff or get the other real stuff with cool recognized name and pay more.

1ADan

iTrader: (4)

while i agree that dynamat is a bit overpriced, many of the other brands are higher in cost due to materials; only the lower end stuff is still asphalt based. The higher end products are butyl based and have better dampening properties than the older and messier asphalt stuff.

you should check out this page: http://www.sounddeadenershowdown.com/cgi-bin/index.cgi

granted, he's selling products now, but the page is very informative on the subject

chevysurfer

Im not even sure why I wrote this up, it was late and I was bored. I was searching thru the audio forum looking for ideas, and alot of guys where asking for (approval) or asking if the lowes stuff was ok. I guess some of the responses just irritated me. You know like if it is not dynamat its wrong thats bad information. I have worked with both butyle/asphalt in the middle of the summer in 100+ weather they will become almost impossible to work with by 1 or 2pm if left in the sun. It will stretch and stick to anything if barely touched especially its self. But on the wall both kinds will fall from its own weight if really hot even with primer. Long story short if your on a budget you can use asphalt based just I would suggest some type of extra adhesive, loctite 4 dollars a can you probley need 2. I get mine for free, some for the house, some for the cars, some for the dog house. I use it on everything.

jchaussee

I use same stuff for windows. Moistop is same as grace correct, but I never see it in sheets, just rolls, but maybe I never looked

chevysurfer

yep, same stuff I have never seen sheets of it, we usually get pallets of it containing boxes that are 4' wide by like 60' feet are something. I used the window flashing which is same thing but in rolls 12" wide. I use to have a ton of it. Now I only have about 3 rolls of the 4' wide stuff. Just did my car with the last of the narrow stuff. We use a lot of other materials thats good for sound deadening/weather proofing car. I used a bunch of left over "back n rod" to seal up the back pillers and wheel wells, also roof seams. They also sell a sloppy paste to deadin rattles, we use same **** but I would never put that on my car its rediculious. When im done my car will weigh in a few extra pounds but will maintain the heat and air, and will not have so many creaks and rattles.