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Guest Peter the Greek
Posted

G'day all,

 

Anyone have a good (and cheap[er]) supplier of MLV?

 

Don't need it for soundproofing, rather radiation protection/mitigation.....microwave/EMR to be precise 

 

Cheers,

Peter

Posted

I am also interested in MLV but for resonance damping of my car panels.  

How does it block EMR radiation ?

Guest Peter the Greek
Posted
  On 17/02/2017 at 2:57 AM, Nigel said:

I am also interested in MLV but for resonance damping of my car panels.  

How does it block EMR radiation ?

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From what I gather, its the Barium. They use it in sheet products for x-ray rooms etc. So it "should" work for what we need it for. I can't find any references on the internet though. Its one of those things that isn't specifically marketed for it and people sell all sorts of expensive products instead.

 

Anyone know/have thoughts on this?

 

My knowledge on this stuff is basis at best

Posted

Try an air-con installation or industrial lagging/insulation company. I sourced some years ago that came with a 15mm foam lining on one side covered by metal foil. Often used in acoustic isolation enclosures for noisy pumps, generators, etc. Excellent for constrained layer damping.

  • 1 month later...
Posted

From their website, the lightest weight vinyl is 4kg/m2 and costs about $210 - that's with a delivery - size is 1350 wide x 5m, rolled so could do maybe 2 cross corner traps floor-to-ceiling okay if aiming for 1200 wide for the blanket - their  6kg/m2 is $300, and is the same 1350 wide but only 3m long - these all contain that Barium Salts that you're thinking about, but not at all sure how it goes mitigating Microwave/EMR transmissions - I thought copper mesh screening was used for that but that might be a "James Bond' story!

 

I asked on their website and got a reply (below) from their Geoff Aldridge - very quick reply - prices pretty much the same - remember, the width is the same at 1350mm, just shorter lengths for the heavier material.

 


Please note that for the best quality Australian made Mass Loaded Vinyl, we currently have the following promotional prices on offer for the next 48 hours.

4kg 6.75m2 roll = $199 plus $20 delivery per roll
6kg 4.05m2 roll = $247 plus $20 delivery per roll
8kg 4.05m2 roll = $277 plus $20 delivery per roll

 

We also have a good quality imported MLV product that is 4kg/m2. It comes in 5 meter * 1 meter rolls and costs $110 per roll plus delivery.
 
 

They sound 'on the ball'  -  Not sure if this imported stuff has that Barium Salts you're looking for Peter ...

Posted

Peter wasn't looking for an acoustic solution, but wanted the MLV for something different...

 

My post is a little OT but is in response to jrhill's post

 

  On 06/04/2017 at 7:36 AM, jrhill said:

 so could do maybe 2 cross corner traps floor-to-ceiling okay if aiming for 1200 wide for the blanket

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I wouldn't use MLV in a "cross corner" trap - that's the wrong application for MLV.

MLV used as a "limp mass" is a pressure trap and needs to be close to boundaries to work - very different from absorption which is often deployed "straddling" corners to get an air gap.

 

The approximate maths around using MLV as a "limp mass" pressure trap are:

F = 600 / SQRT(M x D)

 

where

  • F is the approx resonant frequency of absorption
  • M is the surface density of the MLV in kg/m^2
  • D is the depth of the enclosure in cm

Don't try to reverse engineer the units - they don't compute - I did say approximate.

 

The unit needs to be sealed and the space behind the MLV should be damped with fluffy - preferably not touching the MLV so the MLV is able to move freely.

The approximations include the MLV operating as a piston - clearly not the case especially on the edges.

 

I haven't built one yet to test, but will one day.

My "ultimate bass trap" would have two limp mass pressure traps in the vertical corners of a room with absorption "straddling" the front.

View from above

58e6316544db3_ultimatebasstrap.thumb.jpg.a8a1d9ba3a85f043d8aae3156e9cfb58.jpg

 

 

best of both worlds - absorption with gapping and limp mass pressure traps against the walls

 

cheers

Mike

 

  • 9 months later...
Posted

If I remember correctly..Black builders plastic available from Bunnings is MLV and dirt cheap!

Posted
  On 18/01/2018 at 10:08 PM, Prof. said:
If I remember correctly..Black builders plastic available from Bunnings is MLV and dirt cheap!

Flooring vinyl seems to model well also.

Mike




Guest Peter the Greek
Posted
  On 18/01/2018 at 10:08 PM, Prof. said:

If I remember correctly..Black builders plastic available from Bunnings is MLV and dirt cheap!

Expand  

Not the same thing. MLV is thick, heavy and has metals impregnated in it....I've never used for acoustic or soundproofing purposes as I dont like the methodology i.e. very targeted absorbers or difficult to implement for soundproofing (relative to other methods)

 

FWIW, I've used 75 micron laminating film in the past. Sort of makes a 50mm panel behave like a 100mm panel from memory (25mm, plastic, 25mm) or used on the face in strips. I think the black builders plastic is about the same, but when using it as facing, you want it really flat under the fabric or it shows. I've found laminating film better at this as opposed to builders plastic for this purpose - unless you buy it in really, really big rolls

Posted

Where do you get laminating film from?

Guest Peter the Greek
Posted
  On 24/01/2018 at 11:52 PM, Prof. said:

Where do you get laminating film from?

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Online - I cant remember where I got the last roll. Its something like 200m+ (maybe even 500m) so it catered for the last build and will cater for the current and probably next

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