Sound deadening on the cheap!

https://Bostik Flashband Grey 10m x 150mm (55009)

Firstly a big thanks to @Apportable for one of his brilliant idea's!
I am in no way comparing this stuff to Dynamat or any other sound deadening product but it works!
I decided I would try it on both front doors. There is limited access so it's not just a matter of cutting lengths and sticking it on.
It has to be cut in strips and fed in place piece by piece. I used a hairdryer on each piece for about 15-20 seconds which just made it stick essier.
I think the reason why it works so well is that there are two crash bars running across the door width..one top and one bottom.
They are bolted each end and Rover used a few blobs of glue between the bar and the outer door skin to stop rattle but they resonate with the door skin. 
I wrapped pieces around each bar and everywhere in between. It's a bit fiddly in places as you have to feed it through the apertures and work blind but I made sure I covered as much as possible.
I couldn't wait to close the door and as M says they clunk now without that zing or rattle. That was sounding hopeful so I went for a run and noticed the difference immeadiately. 
I have to drive down a forest road before I hit tarmac and it was so much better. Scuttle shake did not set the doors off.
I am a musician and on stage if the bass player plays a note in between songs the snare drum will rattle in sympathy and I believe those bars and the door skin were doing the same. 
It's not that this tape has miracle sound deadening properties but it did stop that resonance and in all honesty I am blown away.
To be continued...tomorrow I will buy another roll and stick it to the engine bay cover, under the bonnet and maybe in the boot lid. 

So far I have done the floor pans, behind the seats,behind the dash but the biggest difference has to be the doors. 
Instead of a rattle it "clunk's " and makes it sound like a different car.

I agree totally..a different car. 
Can't wait to get stuck in again tomorrow!

So today I did the engine cover and bonnet.
I covered the whole cover and cut around the bolt holes. It stuck nicely cos I had been out on a run to get another roll of tape. 
I filled in the gaps around the bracing under the bonnet as neatly as I could. I will do the boot lid and find places to do with whatever I have left.
Went for a drive afterwards and the car is so different. The suspension is still jiggly but it doesn't set the rest of the car off in sympathy! I lifted the bonnet to see if any had dropped off but it was all intact.
It has transformed the car so I can only imagine how good it would be with the proper stuff. 

Please can you link to the stuff you used on Ebay or Amazon ?

https://www.screwfix.com/p/bostik-flashband-grey-10m-x-150mm/55009?tc=AD5&ds_rl=1249416&ds_rl=1241687&ds_rl=1245250&gad_source=1&ds_rl=1247848&ds_rl=1245250&gclid=CjwKCAiAxea5BhBeEiwAh4t5K4q2mbjgyFo3QqqgnAAM4G5wXuapHwtVX_o2D3gn4yAsuPihqUUiGBoCxuIQAvD_BwE&gclsrc=aw.ds

I am genuinely pleased with the difference. It's not a placebo!
One roll does 2 doors and enough left for a third which I used elsewhere.
In hindsight I would have doubled up and used it all in both doors. 
The door bars are the culprit against the door skin.

When I first got the car I took my wife for a spin and asked her what she thought.
She said it was "like riding in a tin can" and although it annoyed me she was right.
Not anymore...that zing has gone and although we aren't at Merc quality the imptovement is very noticeable.
A hairdryer makes it really stick. A heatgun is too much especially around wiring!

https://www.amazon.co.uk/Bond-Flashing-Tape-225mm-10Metres/dp/B0057FU69I/ref=asc_df_B0057FU69I?mcid=705e1e13a54d38439eba36997cef9ec5&tag=googshopuk-21&linkCode=df0&hvadid=697313183651&hvpos=&hvnetw=g&hvrand=6121744564645961281&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9212541&hvtargid=pla-740920208825&psc=1&gad_source=1 I haven't used it on a car but have used a similar product to repair corrugated metal roofs, providing the surface is clean it will last for decades. What I used had a  thin aluminium foil to reflect the heat of the sun. There is absolutely no reason that due to being thicker than Dynamatt it will not be equal or even better at damping panel vibrations. 
 

I have used that aluminium backed tape but on a flat roof!
I actually looked for thst but this came up locally at Screwfix.
As you say it is the vibrations that set up a resonant frequency that pass through the car. 
This stuff tames that and I'm sure anything similar will do the same.
I really hope someone else tries it and reports back!
 

For anyone who has not yet had to remove their door card.

Almost every car I know has a square mat stuck on the door panel to deaden the panel. It can be very thin but either way it helps cut vibrations.
The TF has no such mat. It is quite a long panel and as such has quite a large surface area.
That's why this tape  or other means, has such an effect on the car. It may have zero effect on a Golf.
By removing the speaker you can gain access to half the door with a bit of a wiggle and the other half by the aperture.

wrote:

A hairdryer makes it really stick. A heatgun is too much especially around wiring!
 

You have the wrong heat gun, the best type has a variable temp control that lets you dial up (or down) to the required temp, mine goes from 70C to 600C
It's wasn't expensive as it's not even a good one, just some crap private label brand of the store.
The only reason I bought that one was I needed it in a hurry and they didn't have the good brands in stock, it came with a shit load of attachments which are useless as they don't fit properly but I've had it for years and it's never let me down. The gun itself is quite good, though a Bosch Professional (blue) one would be better.

Pro tip. some Power tool brands like Bosch have different levels of product, In the case of Bosch the green tools are cheap handyman rubbish at premium prices but the blue Professional range are very very good, they are built to last have good balance and controls, you can actually feel the difference when you use them. which is why most of my stuff is Bosch blue or Hilti (hideously expensive but absolutely brilliant), with a smattering of Metabo and some old Japanese made Makita, The old Japanese made Makita last forever and are unbreakable, the modern Makita stuff (Mostly made in China or some such) is OK but not the same quality as the old.
Oh and there are some Aldi rubbish battery tools kept in the Ute at all times in case of emergency, in there are an angle grinder, a drill, a small impact driver and a !/2" drive rattle gun (i don't really care much if they get wet, damaged or stolen)
 

My heatgun is shit! How did you know? Even from over there you knew..I'm impressed...mind blown.
It actually is..a Low and High switch meaning Burnt to Incinerate. Tbh I hardly ever need one.
The hairdryer felt safer poking it inside the holes where wiring is abundant and if it will burn you can bet I will burn it.
It's cold over here now and 20 seconds just softened the bitumen enoigh to mould it and really stick.
I have some great tools and some cheapo's that were probably only bought expecting one useage but if they made two I got lucky!

 

Well it survived a very heavy frost. Phew!