Dynamat - Opinions

[Waspy]

I would post this in the audio section but a) It's not technically audio related and b)That section doesn't see much action.

I have finally got my mk2 watertight (fairly sure, more testing will be done) so have decided to rip out the old water damaged carpet and felt and do some sound deadening while in at it, as it is fairly loud on the motorway.

Been reading loads about products such as dynamat and alternatives and a lot of people suggesting flashing tape as it is "just as good, and much cheaper" the just as good part I get as the physics behind it makes sense. It's almost identical weight per metre squared. But cheaper?! Here are my sums.

Dynamat: Amazon, extreme bulk pack £140, 30m square. £4.60 per metre squared.

Flashing Tape: Butyl version (screwfix, don't want a bitumin smell) is £19 for 10m x 15cm roll. So 1.5m squared. £12.60 per metre squared.

What am I missing?! Flashing tape is way more expensive.

 How have others deadened their mk2s?

[VW BUSH]

Used to use old carpet tiles on old Ford floor pans.
They cut to shape and work a treat, hint of bodge about it but who cares when its under your carpet.
Can be had for free if you dive the skips at a building site

[Waspy]

Haha, I'm not bothered about what's under the carpet as long as it works. But do carpet tiles really add enough weight to stop it vibrating?!

[Santiago]

I've got a feeling that you could do about half a dozen Mk2s with 30m², so your price per m² only makes sense if you know a number of other people willing to buy your surplus @ £4.60/m² + P&P  (or you have half a dozen mk2s that need doing  ).

[Waspy]

In all honesty i have no idea how much I need. It comes in 9 sheets of 32" by 18" so to get 30%+ coverage I was thinking 2 sheets to get good coverage in the boot (obviously a loud part of the car). 1 for each rear wheel arch. 1 for front left and right floor pan. 1 on the roof. Leaving 2 for the doors and misc. Might be wayyyyy out with that estimation though.

[Santiago]

Some dodgy maths in here somewhere.

32" x 18" = 576 square inches = 0.3716m²
9 lots of that comes to 3.34m², not 30m²

 

[Waspy]

Some dodgy maths in here somewhere.

32" x 18" = 576 square inches = 0.3716m²
9 lots of that comes to 3.34m², not 30m²

 

Yep. I was out by a zero. Excellent, I knew I was missing something 

Ashamed to call myself an accountant 

Anyway, that makes the flashing tape much cheaper. As the internet already told me.

[Sgt_Lemon]

There are some other versions on eBay, from people who have done it how much coverage is needed? I thought it would only require a complete cover onnce over and didn't consider double layers being needed.

[Waspy]

Dynamat recommend minimum coverage of 30% (same should be for a similar product) . So if all of your panels are completely covered, you probably have 3 times that. Doubling up isn't normally required really.

I'm reading a lot of good things around "silent coat", which is about half the price of dynamat.

[Sgt_Lemon]

If there is a bulk buy that would cover two cars do you wanna go halves?