Fabric to cover mineral wool

[Diffusion]

does it matter what fabric i cover my mineral wool in? also i was thinking, because i dont want little bits of fiberglass floating around, should i put two layers of fabric over it or is that a bad idea? and one more thing.. does it matter what i use as a backing? so far i am just going to use plywood or dry wall...

[Gorty]

Use a material that is not to thick or tightly woven, a little test what to use is to put the material over your mouth , you should be able to draw air in and exhale easily. One layer should be suffice to cover your mineral wool as long as it is pulled tight and your mineral wool is snug inside your framework.

As what to use for a backing it is best to cover the front and back with your material. You want the sound waves to penetrate right through your traps or clouds or whatever it is you are making.

[Diffusion]

i wasnt gonna put the mineral wool in my wall... i was gonna cover the walls of my booth with mineral wool and then cover them with fabric... you know what i mean? is that a bad idea?

[Gorty]

Covering your walls with mineral wool 4" thick and then put your cloth or material over that is a good way to go. The idea is to keep sound that is in the booth in and the sound that is outside the booth out.

Using cloth to cover mineral wool is merely to keep the fibres from escaping and allowing the sound waves to penetrate into the mineral wool to be absorbed. It doesn't serve much purpose as an isolating medium itself. One layer of material will be fine or if you want two layers of cloth to eliminate what possibility there is of loose fibres floating around use a thin material doubled over to once again allow sound to penetrate and not reflect.

[Dan Merrill]

Is this a trick question? If you're using MINERAL WOOL there will be no FIBERGLASS fibers- two different products.

Mineral wool is not itchy stuff, but it's also not as rigid or lightweight as fiberglass and I suspect it may sag and bunch up if hung on a wall without proper support. I've only used mineral wool on one project (fiberglass many times) but would guess that to get a clean finished look on a wall ( or in a frame) with it would be a bit more work that using rigid fiberglass boards. The back needs no material if your frames are against a wall. In fact if future removal is not a huge factor, you could even glue/ staple /fasten securely/ etc a 2'x4' sheet of mineral wool to the wall then make a frame (2'x4'x4" I.D.) with material on one side to cover it.

[Gorty]

Dan,
I have never used mineral wool, only used the rigid fibre glass myself. I have not even seen or felt mineral wool, I assumed there would be some form of fibres present with the mineral wool.
But as the old saying goes: You know what happens when you ASSUME!
It can make an ASS out of U and ME.

[Diffusion]

my bad ive never seen mineral wool myself either i thought it was just like fiberglass... but to put them on the walls is it alright if i drill each corner of a sheet to the wall? that should stop it from sagging down or anything like that right?

[Dan Merrill]

It may have fibers ( mineral wool) , but they aren't glass so you don't get the scratchy thing going on. I used some 1" on a project and enjoyed this aspect of it. it is also heavier in weight than fiberglass board which caused me not to use it in larger cloud situations. I didn't want to concern myself with securing any extra weight on the 4' x 8' x 4" panels I was building.

as far as frames- it's easy to put 703 into a light woodframe and wrap it on one side with material and bolt it to the wall, the 703 is light enough that it just sits easily in the frame with no backing or even any sort of attachment to the frame. I'm not so sure this is true of the mineral wool as it's somewhat more flimsy in general. which is why i suggested just securing the raw mineral wool to the wall and then cover it with a cosmetically pleasing ( preferably fireproof) frame. In thinking this further i don't think I would try this hanging method with a 4" layer of mineral wool but 2" would probably do just fine.

the 1" mineral wool i used was on the wall inside of a helmholtz resonator. i used drywall screws to secure it to the wall and then built the resonator around it- using the wall as the back of the resonator.

[Gorty]

If you are going to use the mineral wool you may have to brace it with some strips of ply at say 1' intervals, however if you have not yet bought your mineral wool, the rigid fiberglass has better properties for absorption, I don't think the price difference would be to great.
You will end up with a better isolation booth using the rigid fiberglass and when covered with cloth no fibres will escape. The fiberglass will need less support as well.


Dan, I was writing my post, posted it and in the five minutes it took me to post you had replied to Diffusion, sorry if I repeated anything you said.

[Diffusion]

i think im still just going to get the mineral wool... i dont see how if i screwed it into the walls on every corner of each sheet how it could sag... then cover it tightly with fabric... but anyway how thick should i get the mineral/fiberglass?

[Gorty]

Ideally you want at least 4" inches thick, most comes 2" thick, double it up! In the long run you will definitley be better off using the rigid fiberglass, if you do a search you will find most home recordists use the rigid fiberglass over the mineral wool.

[Diffusion]

would 3" work? take a look at this...

http://www.insulationworld.com/prodV...?idproduct=395

[Diffusion]

alright look... my booth is going to be 4' wide both ways (a square) and 8' tall... the total area to cover each wall with the fiberglass i just posted a link to is 128 square feet... so, the total cost of that fiberglass will be $351... a bit more than i wanted to spend...

http://cgi.ebay.com/AURALEX-SONOMATT...QQcmdZViewItem

that is 96 square feet for only $160... what should i do?

[bileshake]

There's specs for that product if you can find em, explaining the freq. absorption across the freq. range. The way it was shown to me, you want to choose the thickness of rigid that has the most average absorbtion across the range. That way ideally the room will be flat.