G'day All,

Not sure how many people frequent this section of the forum but I suppose that will limit the responses to those who know what they are talking about!

In any event, I am after a quantity of lead sheeting, no more than 1mm thick.

I'll be using it as a noise blocker on the floor pan and baffles (inner door) so I will be in need of a fair bit of it.

Does anyone know where abouts you can aquire such material at a reasonably cheap price? I am willing to travel to Sydney if there are major outlets up there that will doe the job.

Thanks in advance

Plumbers use lead of about similar thickness for flashing. There might even be an adhesive version so I'd give your local plumbing supplier a go.
The only thing is it won't be overly wide, so you will have to do a fair few strips.

Why don't you just use normal SD sheets dude?

We use (Plumbers) Lead Sheeting All the time, most Plumbing supply stores such as Reece and Tradelink for example should have all the standard sizes in stock...

Bob it is available in up to 600mm wide...Maybe wider but i have never bought anymore than that..

I do not like the thought of a lot of heavy, toxic lead in an enclosed environment...but hey...

Liquid
lol - well it is toxic if you consume excess amounts - kind of like salt!

Sorin
Normal sound deadening is a mass loader rather than a sound barrier, which is what lead is. So whilst SD will lower the pannel resonance of larger pannels, applying this to your floor pan which is braced by the chasis rails, made of relatively small pannels, and which resonates at frequencies outside fo the effectiveness of SD sheets means that the overall process is time and money intensive and ultimately useless.


Moose & Bob
Thanks guys, I wouldn't have thought to look for it at a plumbing shop - will give that a burl and see what sizes/prices they have.

Just a thought, SD followed by foam underlay may be much lighter and just as effective. *shrugs*. If you are dead-set on lead though, i'll be interested to see how it all turns out

I can only see lead being a problem if your in constant contact with it. It's not exactly going to break off and float around into your blood stream.
After applying it, you could cover it with some form of tar if you are concerned as Liquidity is.

Liquid
You raise a common point and one which I have been thinking about for quite some time now.
The common misconception is that SD sheets (such as dynamat etc) actually absord or reflect sound in any great mount. In actual fact they don't this at all weel, with the thin foil layer on the Dynamat being the only part of the product dedicated to this. Instead these sheets act as mass loaders which lower the resonant frequency of the particular pannel (I have read through some of your explanations of SD so I know that you are aware of this). However on the floor there are very few pannels which require this kind of treatment as most pannels are well braced, small, and have resonant frequencies outside those that the SD mat can cure.

There are two options that remain then - block the road noise from coming in, or absorb the road noise coming in.

Absorbing the noise is the job of foam and the like - however for an abosorber to be usful it needs to be as thick, or thicker, than 1/4 of the sound wave that they are absorbing. This is great for the higher frequencies, but when we are talking about the lower frequencies this renders them impracticle in the extreme. (The example that I have been given is that of an 80Hz wave which is 4.25 meters long. For an absorber to be effective to such a wave it needs to be 1.06 meters thick!!!)

So then I am left with blocking the sound waves from entering the car in the first place. To this end there are a number of products which I could use - but mass is highly important in all of them.
Lead or rubber then are most effective in this area.
1mm of lead has the blocking ability of 90mm of MDF!!! 4mm or so of rubber is in the vacinity.

So if I can find some lead sheeting at a reasonable price then I will go with that. If not, then some thick rubber and some aluminium foil will be the order of the day!

Regards

100% Agree!

I just bought sheet lead for my floor pan, wheel arches and firewall (whatever's left will maybe go in the doors). It's $147 (trade price) at Tradelink for 1.8 square metres. It comes 300mm x 6m or 600mm x 3m i.e the same area, but the 600 wide is $30 more! It's 1.7mm thick as well.

1.8 square metres has ended up being 37kg, so yes it's MUCH heavier then Dynamat etc, but like was said it plays a completely different role...

Hmm..i may look into some thick rubber then, as a key element of my future SD'ing efforts, and audio equipment, is going to be keeping mass low. Not only in terms of gross weight, but centre of gravity.

Thanks for the info

G'day CoinSlot,

Good to see that I am not alone in this particular pursuit!

I am assuming that as you got this from Tradelink this wasn't any kind of specialist plumbing lead sheeting and as a result did not have an adhesive backing?
If that is the case, what did you use to stick the lead down? Obviously a contact adhesive of some description, but if there was a brand that stood you in good stead I'd love to know!

Regards

Well I hope you dont wanna dB Drag.. lead sheets arent considered a sound deadening material.

Hey Steve,

Yeah not really interested in the DB Drags side of things. Whilst the events I have been to a fun, I don't think there is much damage that I would be make with a Ford Sedan and my SQ efficient subs!

Thanks for the headsup though - I hadn't considered this

It's just a roll of lead, no backing, no covering. I haven't put it in the car yet because I'm waiting on some brackets to be welded in first. I honestly have no idea how i'm going to stick it down. I thought about laying down some cheapo deadener and glueing it to the deadener so that it isn't stuck to the car itself.

Maybe look into the dissimilar metals contact also. I'd tried and isolate it with some form of barrier from the metal of the body, as you really don't know if it will have any anode/cathode effects on it.

http://www.jaycar.com.au/productView.asp?I...eMax=&SUBCATID=

Would this work??

most floor pans already have the sound deadener applied (on newer cars, anyway) so the lead would sit on this, and not contact the vehicle body.

Thanks for the help thus far lads!

Teg:
Thats a very interesting link! I had been referred to look at some mass loaded vinyl sheeting, but the cost of that was more than the lead sheeting itself - for similar results.

The sound transmission class (STC) is pretty high for a product of that density and thickness too which is a plus. I will ask around some more to see if these figures are reliable and comparable to those parameters that I was initially seeking.

The upside would then also be not having to decouple the lead sheeting!

BMW & Coinslot:
My thinking behind the lead sheeting would certainly be to decouple it from the floor pan or the pannels that you are working with. Obviously this will be much easier on the floor pan as gravity will hold everything in place.
That said a think layer of closed cell foam or rubber would be my number 1 choice, and both of these can be attached with a spray on adhesive, before the lead is moulded to shape and stuck with a contact adhesive.

Mind you those are just my initial thoughts on the installation!

Just picked up a few bits of that Jaycar stuff (ok, everything they had in stock! lol) also a few of the heavier (4.5kg sqm) dense foam backed stuff. I'll post up when I get a chance to try it, but it feels heavy. Its like fake leather, cloth back and textured front.

Well have been doing some research.

I have calculated that I will need in the order of 7.5m^2 in order to apply one layer to the floor pan, doors and sub box baffle.
I did some ringing around about pricing on some different products and found:

7.2m^2 of 2mm Lead = $440
7.0m^2 of 5mm Rubber = $301
7.0m^2 of 1mm Aluminium = $165
7.0m^2 of 2mm Aluminium = $302
7.0m^2 of Jaycar Sheeting = $279 (the one linked above)
7.0m^2 of Jaycar Xtra Sheeting = $465 (an improved version found here)

So lead would be more expensive than its counterparts (with the exception of the new product Jaycar is bringing out!) but is it worth the extra?

The density of a material is the key property in blocking sound energy as this is what helps the material convert the sound energy into small amounts of heat. What then is the comparatable densities of the above materials?
Lead = 11.34 g/cm^3
Rubber = 0.92 g/cm^3
Aluminium = 2.70 g/cm^3
Jaycar 1 = 1.74 g/cm^3
Jaycar 2 = Not specified

So then the lead sheeting is in the order of 5-6 times more dense than the Jaycar product listed above and more than 12 times as dense as rubber! Of course the increased thicknesses of the rubber means that it would actually block more that the Jaycar 1 product, as the Jaycar product is only 2.3mm thick.

So as things stand at the moment:
Floor:
~ The lead is a hands-down winner as it is maliable enough to mould into the shapes required. It is also thin enough so as not to significantly get in the way. The only down side is there may be the need for decoupling from the floor through the use of a thin layer of closed-cell foam.
~ I would prefer to spend the $30 extra dollars on the rubber matting over the Jaycar product as it will simply do a better job because of it's increased depth. That said this is a drawback as I don't really know how well the carpet will go back over something that is 1/2 a centimetre higher!
~ The aluminium would give the rubber and Jaycar product a run for their money, but as these sheets aren't as maliable they are probably unsuitable for this application.

Doors:
~ The lead again will provide the best blocking here as well. Again being maliable is a huge advantage and it's thickness should not impact on the ability to re-position door-trims etc.
~ The rubber matting in this instance would be significantly too thick for my application.
~ The Jaycar product here might just come into its own as it is fairly thin but is also lightweight compared to the lead. This will mean sticking it in place will be much easier.
~ The aluminium would provide better blockage than the Jaycar matting, but again maliability of the product might mean that it is unsuitable. In my application the inner-doors are all but flat which means that the aluminium sheeting would probably be alright.

Obviously if you aren't concerned with fuel efficiency, the fact that you are driving a boat, or the fact that you just threw ~$500 at sound barriers then the lead is still my choice.
That said, car audio is all about compromises so whilst I am seriously considering the lead in the floor pan, some compromises, perhaps in the form of Jaycar sheeting or aluminium sheeting, might well be in order...

Whoops!

I forgot to add that with the Aluminium sheeting on the doors that you would have to be careful about it resonating. SD would probably be required!

Big thanks to Abmolech also for his technical advice thus far behind the scenes!

Go the lead you pansy!

Ablomech is a crazy man with crazy ideas. Also my inspiration for the lead

lead is used in industry for a very good reason - for it's thickness, it's very hard to beat. (in terms of noise reduction - duh!)
and very easy to beat with a stick

lead huh, is your car nuclear or something

Mine is...

Only way to move all the lead around hahaha

some very strong glue will keep your lead sheeting down.. i've seen it done in NZ.. very quiet car

what i would suggest if ur trying to source lead. make a friend who is evaprotive aircon installer. he will then source u rolls of 1-2mm 900mm or 1200mm by 1.5m rolls. he would be able to get them through his work far cheaper then u could imagion. i know as i run a warehouse that supplies heating and cooling products lol. ie if u are in perth ring up Advantage Air or Air group Australia and say i need some rolls of lead to do some flashing for a ducted breeze air. they will say sure that will be 32 cents sir.


chris

Ya known, weight and thickness isnt the be-all and end-all of sound absorption.

its been a month, have u guys tried these products yet?

I haven't yet. But then again my car won't be on the road for ages so it doesn't make much difference to you.