ok im after answers from people with actual experiance/results.

car: 1996 accord wagon

im very interested in the cost savings of using "flashing" tape like you would dynamat. now i have dynamatted my doors very thouroughly, and loved the results. i am looking at using the flashing throughout the boot, where i already have a fair amount of bostic applied already.

do you think i will get any results with the flashing?(the flashing will be applied over the bostik)

also for the floor pan, i have access to a variety of carpet underlay's, will i get much road noise cancellation by adding a layer under the factory carpet? maybe flashing + underlay, then the factory underlay+carpet.

i did exactly this a few weeks back

the difference was huge, total cost about $300, that will vary depending on how cheap you get the flashing tape for
I also put 11mm heave duty house underlay behind all the panels, esp. around wheel arches, and stuffed all the spare bits into places that were hard to get to with the flashing tape

you will need 2 layers of flashing tape, and lots of free time, i suggest afternoons are good, as you can leave the tape black side up in the sun for 30 secs to warm up before applying it


about half way down
http://www.nzicemag.co.nz/forum/viewtopic.php?f=11&t=23369

I'd say be careful of the product you use. After 4 years my flashing tape has turned to a sticky mess.

To be totally honest, for ease of use and piece of mind, I'm only sticking to Dynamat from now on.

i was wondering what the long term life expectancy of the tape was, also why ive only used it in the boot area
and ive covered most of the edges in aluminium tape too, so hopefully any bleed will be minimised

im planing on using dyanmat on the doors, in case

Now I've read the question properly...

You have already mass loaded with the Bostik. The further benefit you'll get from flashing tape is a little more mass loading, and some blocking properties from the alloy layer. Unless it is the boot floor, I wouldn't say blocking is going to be a great benefit.

At least with the flashing tape I used, if you stick that on your boot floor, it is just going to be a foul mess. Stick to blocking materials there.

Underlays can be used to absorb sound, but unless they are closed cell, they're also going to absorb water and introduce other problems. I used some underlay on my cabin floor... can't say I noticed a great deal.

hmmm mixed results then.

so my rear quaters are currently standard, would you recommend bostik or flashing?

where your flashing has turned to a sticky mess, was any of that on a vertical surface? did it stay adhered to to the surface?

for the underlay, i talked to our carpet guru, and he is getting me a sample of a special underlay that is reccomended for noise cancelling between floors. it apparantly has an air bubble layer thingiemajig which is meant to help. but the closed cell thing is definitly something to make sure it has.

what im basically trying to do in my vehicle is cut out as much road noise as possible without spending thousands on dynamat.

I'd be using Bostik on the rear quarters. When I did my rear doors/quarters I didn't notice as much a drop in road noise as more detailed sub bass. It is also very quiet outside the car, even with two 12" pumping dubstep.

Sticky mess is vertical. It's semi-adhered, but on the move. Needs ripped off and done again with Dynamat. I'll be using something other than MDF to seal the holes this time. Even with copious amounts of paint it has turned to Weetbix.

With regards to the floor, from what is said on here, lead seems to be the ultimate to use. Pauls Audio stock a product that is a foam sandwich with lead filling. Supposed to be good (not that I've experienced it).