Sheets/plates of lead

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Sasha,

Use care if you are working with lead, as it is poisonous.

http://en.wikipedia.org/wiki/Lead#Health_effects

You have an interesting idea, but the acoustic properties of lead may not be as favorable as its weight might suggest. If you are trying to dampen the walls of your enclosure, I imagine there are better performing materials for this task which are safer and easier to work with. Thick rubber or something with similar elasticity would do a better job of dampening vibrations in enclosure walls, I should think.

J.F.
 
I failed to mention this in my first post, but my brother and I had the idea of using lead sheets for this very purpose.

We would use different layers of material and bind them together through some "rubber type material". We're still working on finding a decent "rubber type material" for the job. We tried some asphalt based roof sealant, and that seems to work pretty well. Other then it took forever to dry, and was petroleum based.

If your not planning on doing some type of layering, to help dampen your added mass, then i would choose some other material as J.F. mentioned.
 
SpJonesKSU said:
We're still working on finding a decent "rubber type material" for the job. We tried some asphalt based roof sealant, and that seems to work pretty well. Other then it took forever to dry, and was petroleum based.

You can try real tarmac tar. It's basically the same except that it's not even liquid before heated to about 50-60 degrees (celcius) and therefore harden pretty quick.

For those considering using lead plates. Please remember that it's both extremely poisonous and inviromentally hazardous. Make sure you clearly mark your speaker as containing lead and make plans for how to dispose of them safely after you are done with them.
 
I am a roofer.

I too am building my own speakers.

I too will be lining my speakers.

Any big Roofing supplier has many options.

SBS membrane, soft, 4mm thick, 1 meter by 10 meters, $60.00, smooth surface or granulated, prime your wood (with their primer), use a plumbers propane torch to heat up the back of the membrane, stick it to the wood. Remember to keep the corners really rough and non uniform.

APP membrane, slightly harder, same cost and installation procedure as above.

Peel and Stick flashing, softest, 6" and 12" widths, simple to use, more expensive per square foot then the above, easy to make triangles for all the corners. This is what I will be using. I will also install it really poorly and un-uniform, many kinks and over laps.

Roofmart, Spar Marathon roofing supply, Hermans building products, Convoy roofing supply, and many more.
 
Well, I was thinking of applying borosilicate paint to the internal walls, then a layer of lead, followed again by borosilicate paint, and finally by some absorption layer such as the one in the following link:
http://www.parts-express.com/pe/showdetl.cfm?Partnumber=260-530
Reasons for borosilicate paint is that many manufacturers use it with apparently good results (for example, Totem, VMPS), same goes with lead, Wilson Audio does it for example.

Now, what do you guys think about the actual installation, how do I make sure lead sticks to the wood and does not come off later on?
Do I simply glue it using some universal “crazy” glue?
Would the borosilicate paint hold it?
Or should I nail it to the wood? Screw it in?
 
I too am in roofing and the only thing I can add to Billy's comment is to add EPDM (synthetic sheet rubber) to the mix.

Also, APP is not readily available on this side of the country but can't comment on the east.

Do not use any cut back asphalt type product (mastic, roof repair in a can, etc) as it will continue to gas off for a long time. Be careful with the peel and sticks for the same reason.

6 pound sheet lead (used to interface with roof drains) is very expensive and very heavy.
 
Decades ago, recording and broadcast studios often had a layer of sheet lead in the walls. Pound for pound (or kilo for kilo) sheet lead is a very effective sound absorber.

From the 1969 "Audio Cyclopedia"

It has been demonstrated that if two equally effective barriers are constructed, one of lead and the other of conventional building materials, the lead barrier will be the lighter of the two.
 
My father worked with lead for years years ago along side his father. It really isn't as dangerous to work with as some would want you to beleve. You really just have to wear protection if you cut it or anything that would cause it to become powered. Also don't lick it or eat it., that is why kids used to get lead poisoning, lead is sweet tasting so they pick it off the walls and eat it. Just use some common sense and you won't have to worry.

Also as theAnonymous1 hinted at a bit, think of the shipping cost, lead is very heavy! Of course you cannot line with it but lead shot works good to dampen. You can pick it up at your local sports store that sells reloading stuff, no shipping and fairly inexpensive. Again don't eat the little marbles, wear some gloves if you want, at least wash your hands before you eat if you don't wear gloves.

My 2 cents

Cheers

James
 
theAnonymous1 said:
I wonder how effective a layer of lead shot held in place by something like "green glue" would be.

You could build a frame that holds a single layer of lead shot, spread a layer of glue on the speaker panel, and then lower the panel onto the shot.

Green Glue, despite it's name is not GLUE!
You really need sheet lead, lead shot would be no better than steel ball-bearing and I don't think that ball-bearing would do anything.
 
You could also maybe check into the fishing industry for an economical way to make your own sheets of lead.. You used to be able to buy molds to make your own fishing weights and cannon balls etc.. If a person was so inclined, you could look into making a structure and pour your own small sheets, to whatever thickness you desire etc.. Of course you would have to take it very seriously, with all safety practices to ensure everything is done properly.. We used to melt lead in metal shop in school also, and make stuff with it, it's not rocket science and quite easy once your schooled in all the safety procedures etc...

Also there really shouldn't be any health issues once the lead is installed inside a cab or sandwiched etc.. If you had lead inside a wall in your house your not going to have any probs with health.. The main issues with lead started with stained glass workers and water pipes that were made with the stuff ,and also lead solder on water pipes and food cans,plus lead paint that people or animals may chew on.. Same with asbestos, it's not a prob until it becomes airborne and breathed in, same with coal dust etc.. You could eat a small piece of asbestos and be ok, its only harmful when in particles.. Same with mercury, its ok in your thermometer, but if you get it on your skin or heat it and breath in the vapors, or eat it, your in big trouble.. Same with lead!!

In the old days lighthouse's had the light floating on top of a mercury bath, and slowly over the years lighthouse keepers would become poisoned by it and also most of their family also etc, bad stuff... Dave:)
 
Here's a paragraph or two from a book I have called "Keepers of the Light".. The paragraphs are about mercury, but one should pay attention while working with lead also, so while "off topic", it's still kind of neat info..

The primitive though highly effective use of mercury for bearings posed a sinister threat. Even today doctors can easily misdiagnose mercury poisoning as rheumatism, senile dementia, emotional instability, or psychosis. Whether it was absorbed through the skin or entered the lungs, metallic mercury wound its way through the central nervous system to the brain, short-circuiting the processes of emotional response and rational thought. Silent, insidious, incurable, its effects compare in their severity to long-term exposure to radioactivity. Lewis Carroll did not invent the "Mad Hatter"; there were lots of them around in his day, driven mad over time from rubbing mercury into pelts to stiffen them into top hats.
There were at least five hundred pounds of mercury in the tub under the light. Log books describe how a keeper would routinely lower the bath, wipe dust and debris off the gleaming surface with a rag, drain the deadly metal off, strain it through chamois leather, then top it up as required. At a temperature of twenty-five degrees celsius or more in the summer, he was inhaling mercury vapour in the beacon room like steam in a sauna. Family members could be contaminated by residue on clothing, wives through intimate contact. No one will ever know to what extent lightkeepers fell victim to the ravages of contamination. There was insanity enough on the lights, but the tendency was always to dismiss madness as "cabin fever," contracted through prolonged isolation. Dave :)
 
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