Dynomat

Just to correct this post...the material is called "Dynamat."

ok, I have given this secret to a few people and they have been very pleased. Go mcmaster.com. The sound/vibration damping stuff starts on catalog page 3266. On page 3270, you will find adhesive backed dmping sheet. CHEAAAAAP. I used the polymeric mastic (item# 9709T19). IT IS THE SAME AS DYNAMAT.  IT IS NOT SIMILAR, IT IS THE SAME!!  32"X54" sheet is 14.62. NOBODY can match that with dynamat. This stuff works great. And being so cheap, you can double and triple layers easily. Above this product is a 5 gal bucket of roll on damping compound. I haven't tried it but, I am sure it works.  Quit supprting Dynacrap and go get it cheap. It is black and doesn't advertise dynamat all over it.

Ok, I am the man!

It has very little odor. I did my whole car and could barely smell it for about a week. Then it was gone. I used to do competetive SQ contests and used Dynamat. I think it is every bit as good as Dynamat. The only problem is that sometimes the adhesive can be a little weak for spots like the trunk lid where you are constanly slamming it. I am sure you will be happy. I assume you mean a 12' square sheet.

no offense taken. No one here is obligated to trake my opinion either. If you choose to take the cautious route (and I guess you would be smart to) , just order 1 sheet to check it out.  They  take returns, so you can send it back if you would like. I am simply saying it is a cheap effective alternative to Dynamant, Brown Bread etc. All the sound damping stuff on the market is great, however, I think it is all pretty much the same. It is all based on a simple concept called mass loading. To stop excess vibration, you make the surface heavier or more dense. It is that simple. You could cover your entire trunk with about a gallon of roofing tar from home depot and it would work great. It might stink like hell, but it would work. The ice guard is a great idea, except you get all the granular coating all over everything. I did a search on yahoo and came upon this site. I have some experience in sound proofing recording studios and the specs of this stuff seemed great. I decided to take a chance on it and was very pleased. Some people may say I am wrong, but hey, that is opinion right?? And you know what they say about opinions......

"opinions are like a$$holes--everyone has one and they all stink.  "

true enough.  Recording studio?  You don't say...  I noticed they had the foam panels as well, except at a huge fraction of the cost if you bought them from any pro audio retailer.  I'm gonna buy a bunch of them for for my studio!!  People can be very blind when it comes to that stuff as well, myself included...

P.S.  I checked the specs on Dynamat original and the industrial stuff, and strangely enough, they were identical in weight, thickness, and temp range was very close. 

Once again, thanks for the link.  If the damping sheet works out I'll be able to buy from them for my installs and my studio, and the studio savings alone make it more than worth it.

Okay, so I'm done.  Having only used Brown Bread (BB) until now, it's what I'll have  to compare with "mcmat" (MM).  The temp where I am was 1-0 C today, and the vehicle was a 1997 grand prix.  I did the trunk lid with roughly 1.5 layers, and in the trunk were 2 10" subs.  Before starting, I listened to the system with the car off to get an idea of what to reference.  Tools used were; mastercraft heat gun, 2" wallpaper seam roller, my fingers, my thumbs, and a utility knife.

Just before typing this I checked the Dynamat website and found out that the original is adhesive backed, just like mcmat.  I always figured that it would be like BB, but I was wrong.  So here we go:

Before starting, I gave the lid a good wipe to get rid of the dust.  Lucky for me, since it was only after that I had discovered MM had an adhesive backing.

When doing the first layer, I found MM easy to cut and 'pre-place'.  I was using a heat gun, but I can say without a doubt that you shouldn't even bother trying to put MM on without one, regardless of the temp outside.  A hairdryer might work, but the temp needed to bond and mold is fairly high.  My gun blasts out 450C at the high setting, and that's what I was using (you can get one at canadian tire for $35, or $50 with acc.).  Compared to BB, MM was slightly harder to form around the bumps and curves, but much more forgiving when stretching or working around them.  I find that BB is much more likely to split when doing this and MM wasn't, leading to a more cosmetic install.  The downside of course, is that you need some skill if you want to get the MM on the entire surface.  I managed to get it on about 90%, with the other 10% being some of the drastic insets on the trunk lid.  Overall, I'd give MM a 7 or 8 out of 10 for ease of use. 

After putting on one layer, I did the following tests: close trunk, feel trunk vibrations, listen to music.  When I closed the trunk I noticed more of a thunk, but nothing drastic.  When I listened to the same songs I noticed a slight increase in bass output, but once again nothing drastic.  During some songs I could hardly tell a difference and during others it was apparent.  This was quite similar to when I did BB on the lid of my own trunk.  I didn't really feel that the time and effort was worth it.  When I got out to check the lid, I noticed that it was still vibrating as well.

Before starting the second layer, I gave the first a good wipe.  It actually looked pretty good, better than the crinkled aluminum appearance you get with BB.  As soon as I started the 2nd layer I noticed that the MM doesn't like to stick to itself nearly as much as steel, but the heat gun changed its mind.  In a few days or so I'll check to make sure that its still holding, but I don't think It'll be a problem.  Once again, I should stress the heat gun. 

The sheet was 32"x54" (12 sqft), but the grand prix's trunk lid is exceptionally large.  If you planned ahead and tried to cut precise pieces, you could probably do it twice over, but I wasn't planning anything other than finishing since I was cold.

Once again, I did the same tests.  The thunk was more pronounced, but the lid still vibrated.  When I did my sunbird with BB the same thing happened, but the lid was relatively heavier after and vibrated a bit less.  Part of this was probably due to the small size of my lid compared to the grand prix's.

When I sat and listened in my sunbird for the first time after the second layer of BB, the difference was amazing.  4 12's and 2000 rms had taken a whole new meaning.  When I sat and listened in the Grand Prix (2 10's and 200 rms), the difference was easily felt.  My guess is a 3 or 4 db gain.  The subs were almost as loud at no bass boost after using MM, than before with 6 db bass boost at 90hz.  Though not as dramatic as my own car with BB, I guess you have to keep in mind that bigger results should be expected from a bigger system.

So to summarize my lengthy, long-winded review of 'mcmat', I'd give it an overall 7 or 8 out of ten compared to brown bread.  Perhaps not quite as good as BB, the price more than makes up for it, and from what I've read it's the same as dynamat original.  If feel the real difference between MM and BB is the damping factor with 2 layers.  I'm buying a 2004 right away, and I'll be doing most of the car with 2-3 layers of MM.  I will be using one layer of BB in the really tight corners, and probably 2 layers of BB under one layer of MM on the trunk lid.

So I'd say buy 'mcmat' for almost all of your damping.  With a heat gun the adhesive works fine, and @ $14 US for 12 sqft you can do 2 or 3 layers for less than one layer of anything else.  The only bad thing is the inability or difficulty to do tight corners, insets, and what not.  For that I would recommend using just enough BB to fill the corner and then continue with MM.  The trunk lid is also another place that I'd use BB since it's a bit heavier and in my opinion, damps a bit better.  Other than that, I'm all 'mcmat'.  Buy it, you won't be sorry.

i dont know. never used that.

I used some fatmat and was happy with the price. However I ordered the hood kit of theirs and it took 3 shipments and almost 2 months to get the whole kit. First time they sent it it was missing half the fatmat material and the tools. Then they shipped me a second box that was supposed to be the remainder of the material...this time it was only half of what was supposed to be sent. I called them back and notified them of this problem and almost a month later I had a 3rd package with the remaining fatmat in it.

poor service I think