Need help from mineral wool users!

  • Thread starter Thread starter Diffusion
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Diffusion

Future Astrophysicist
Ok, I am definately considering buying mineral wool rather than 703, since it is so much cheaper, but I am a little confused. First, I have heard a lot of complaints that it is difficult to work with, but then, I have also heard comments that it is not at all difficult. Secondly, I have heard complaints that it sags over time... is this true? Basically I am asking those who have used the mineral wool to tell me of their experiences using this stuff, whether it is difficult to work with or not, it crumbles or not, the difference using this stuff made, anything...
thanks...
 
It doesn't crumble - think of it as a stiff blanket. If you hold it from only one end it will fold - but can return easily to its original shape.
The middle will sag if it is only suspended at either end. I can't think of a situation where that would be the case though.
I found Roxul much easier to work with than 703, which can dry out and get very crumbly and "sharp." Think of it as a cookie made with not enough butter, except that it stings.
 
haha.. nice metaphors... so how good does this stuff absorb? how much of a difference did it make when you first used it?
 
My entire room is treated with mineral wool (to be more precise, with Rockstud 204 panels). I don't know the ratings on these things, but here's some facts that I've found out through use:
- Itchy stuff, wear gloves.
- Fragile, looks somewhat like very stiff cotton candy. If it bends far, it breaks. Can't take much weight either.
- To my ears, it absorbs like a mofo. Probably not so much in the lows though.
- Yeah it's a bit nasty to work with but nothing too bad. I used gardening gloves and a breadknife to cut the panels to the right size, then made a wooden frame around them, and covered that with cloth. Once it was all done, the panels are very handlable and won't break that fast. Don't lean agains't them though.

I don't have any experience with 703, since it's not available where I am, but I highly doubt it will be much different to work with (on the nastyness scale that is). Get whatever's cheap where you're at.
 
ok thanks for the advice... would you suggest getting a 4" thickness to absorb more lows?

Also, what density are you guys using?
 
I'm using 4,5cm stuff, that's 1.8". Me thinks 4" would do much better on the lows, but I would have a tiny room left if I used 4" stuff.
 
I've used both. I personally find the 703 much easier to work with (purely relative - both are a PITA compared to acoustical cotton.) Both materials will perform very well if the appropriate thickness and density is selected for the application.

Once they are up, I find very little difference in them over time. I simply hate how much the mineral wool sheds when you're working with it. This is not to say that the 703 is clean by any stretch - just cleaner than the rockwool.

It's really personal preference and your willingness to trade ease of use for cost. If the mineral wool is considerably cheaper in your area, it's certainly a good option.
 
ok... i thought i found a good supplier of mineral wool but it turns out the stuff they were selling doesnt have very good acoustical properties... what brand and model of mineral wool are you guys using and where did you get it from? If you could tell me exactly what brand it is and what model that would be great..
 
I think most people use Roxul. Seems to be readily available.
 
I used Roxul AFB (acoustic fire batts), 3 lbs per cubic foot density. I used 16" wide, 3" thick panels in between the studs during construction and 2'x4'x2" panels for acoustic treatments. I used two panels per trap, so each trap is 4" thick.

The Roxul will shed in clumps but it's easy to clean up.

I used 703 for ceiling clouds since they are more stiff and hold their shape. This way I could just hang fabric-wrapped 703 panels from the ceiling without building frames for them. I figured the lighter the better for ceiling traps so it's easy to support them and if there's ever a failure, I'll get a nice light tap on the head instead of a resounding thump.
 
everywhere ive looked though roxul only seems to be available in cananda... i have been looking for roxul for a while but cant seem to find a dealer within the US... could anyone help me out with this? I live in georgia...
 
ok this is frustrating... i have tried that link before (saturday) and I still havent heard from them... i tried again yesterday but still nothing... this is the stuff I know I can get... will this stuff work as good as Roxul?

Sound Attenuation Fire Batts Data Sheet

another link (same stuff)

Pics

I can get a pack of 4 4" boards of that stuff (2'x4') for $24...

or should I look for something else...?
 
Looks like it should work fine. Nominal density is just slightly less than OC 703 but no big deal - it just won't be as rigid. Performance wise, it looks fine for a variety of applications.
 
:( I hate that word... "fine"... its just isnt very assuring... its nominal density is 2.5pcf... I have been told that there is barely a difference between 3pcf and 4pcf, so I dont see why .5pcf will make much difference... it states in the description though that these are flexible, not rigid... will this affect anything?
 
Roxul is made by Rockwool. Maybe that's available in your area. If you are able to go with Roxul, the Safe n Sound is better than the batts, it's more dense.
 
Is Rockwool the same as Rock Wool Manufacturing Company?

http://www.deltainsulation.com/index.html

The company I am trying to go through carries this stuff... I asked them if they carry Rockwool Safe Insulation and they said yes, but earlier they told me they dont carry Roxul products... Im not sure if they think I am meaning Rockwool not Rock Wool Manufacturing Company...???
 
When I say 'fine' I just meant you should have no problems with it - other than the lack of rigidity. The only time that would really be a huge issue is when doing ceiling panels. In that case, I'd get something a bit more rigid. Even 3lb 703 works just 'fine' for that ;)
 
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