Tissue to face Rockwool Slabs

[fitzj]

Hi
I am looking to purchase Tissue that I can put onto Rockwell but not sure what type to get. I asked a company in the UK about Glass Fibre Tissue and they said it was not suitable.
Message from Rockwool "The product does not require netting to keep the fibres together, however, if it is behind perforated panels where it will be visible then we can provide the product with a black or white tissue facing"
What is this tissue made form as I do it myself as it coming to £22 per Sq meter to get done commercially and that only one side.

[Soundman2020]

Hi. Please read the forum rules for posting (click here). You seem to be missing a couple of things!

But why do you want to cover it with tissue? For what purpose?


- Stuart -

[fitzj]

HI
Not sure what rule I missing please explain.
I need to cover the rockwool slab myself. Over time they the sound breaks up the fibers and they get very dusty. They already have a slab covered with tissue on one side and I wanted to cover all sides.
http://www.rockwool.co.uk/products/u/20 ... W5,%20RW6)

[Soundman2020]

Not sure what rule I missing please explain.

It's OK: you fixed it now. The problem was that you had forgotten to fill in your location in your profile.

Over time they the sound breaks up the fibers and they get very dusty.

Are you talking about using the rockwool inside an HVAC duct? That's the only place where the fibers are eroded, but that's due to air motion, not sound waves. That's why proper duct liner should be used inside HVAC ducts and silencer boxes. Sound does not "break up" mineral wool fibers. There is very little energy in sound waves: certainly not enough to break fibers. Maybe one watt per square meter, give or take a few milliwatts. Way short of the energy you'd need to break down rock fibers.

Like the manufacturer says: "The product does not require netting to keep the fibres together".

However, with loose mineral wool (not the semi-rigid slabs in the link) some fibers can come loose over time, naturally, and can filter down all over your equipment, which is why we recommend using thin plastic sheeting under ceiling clouds and other places where mineral wool is located overhead. You can also do that on the front of bass traps, but not on slot resonators or perf panel. For those situations, plain black cloth between the mineral wool and the slats (or perf panel) does the job very well, if you don't want to buy the mineral wool slabs that have the colored finish.

Like the manufacturer says, the black (or white) tissue is only there for aesthetic purposes, not to prevent the fibers from "breaking up" due to sound waves.

There's no need to worry too much about mineral wool shedding fibers over time, if you build your acoustic treatment correctly.


- Stuart -

[fitzj]

Many Thanks for the reply.
like the manufacturer says, the black (or white) tissue is only there for aesthetic purposes, not to prevent the fibers from "breaking up" due to sound waves.
What type of tissue paper is used for this job as I will cover the back of them to make them look better?

[Soundman2020]

I think you didn't read the above very closely! Just use ordinary black cloth across the back of the slats or perf panel, in between the wood and the mineral wool. Any type of breathable fabric is fine, and it does not need to be thick or expensive. Just black coloured, and with a fairly fine weave so that it hides the mineral wool well.

If you try to do this yourself, you stand a vry good chance of messing up the acoustic properties of the slab.

What type of acoustic treatment are you trying to build with this insulation? It would help a lot if you could explain in detail what you are trying to do, and provide diagrams or photos so we can understand better, and give you more correct advice.


- Stuart -

[fitzj]

Hi
I managed to track it down. It's Fiber Glass Tissue Interwoven 100gsm. Comes on Rockwool slabs in Black and White colours. Could not get it near my home so I will order the rockwool and the tissue separately and cover the backs myself. Looks more professional job.

[Soundman2020]

And how do you intend to bond it to the mineral wool? You can't just use spray glue... That would alter the acoustic properties of the device you are trying to build. The factory likely resin-bonds that thermally, as part of the manufacturing process, not with glue...

Once again, if you provide more details about WHAT you are trying to accomplish, then we can give you better answers. You keep on saying that you want to do this, but you haven't yet said why. There are cheaper and better ways of doing what we THINK you are doing, but if you won't tell us what that is, then we can't help you much!

So far all we know is that you are trying to prevent something from happening that won't happen anyway, for reasons that don't make a lot of sense, against the advice of both the manufacturer and the moderators here, and you are also choosing to ignore advice about how it is done in professional studios, preferring to do it your way due to some unexplained obsession.

By the time you have bought the tissue, had it shipped to you, bough the resin, had that shipped to you, figured out how to cure it thermally and rented the equipment to do it, it would have been cheaper (and faster) to just buy it ready-made from the factory, even at the higher price. At least that way you would be certain of the acoustic properties of the end product, since the manufacturer publishes them. If you do it yourself, who knows how it will turn out...


- Stuart -

[fitzj]

Basically I am making corner traps and side wall Absobers. 1200 by 600x 100. I see loads of video's of people making these devices in so many different ways. Some just buy Rockwool and wrap it in cloth, other make frames and put the rockwool inside. I have watched the video's from Ethan Winer Real Traps site and he glues on the Cloth with a spray glue. Some have a tissue also glued on. Is there any right way to do this. All I know is that ones you wrap just with cloth after a few years get very shabby looking and start to sag. if you have good method by all means let me know or point me in the right direction. I await you eager response to make the perfect corner traps and side wall absorbers. I am no expert so I am open to what you present.

[Soundman2020]

For corner traps, Superchunk style bass traps are generally considered to be the most effective by far, so you might want to consider using those, instead of a simple corner trap. Superchunks go down to lower frequencies and provide much better modal damping than corner traps, and take up about the same amount of floor space.

For side wall absorbers, yes there sure are a lot of ways of building them! And yes, if not done right, they can end up looking a bit shabby after a while. But that is often just a matter of not choosing good quality fabric for the facing. Low quality fabrics stretch and sag over time, while higher quality ones don't. So people who try to save a few dollars by buying the cheapest cloth can end up with absorbers that don't look so good, as time passes. It's OK to use cheap black cloth to cover the insulation inside slot walls and perf panel absorbers, since the pressure keeps it smooth and wrinkle-free, and the visible area is so small anyway that it's hard to notice imperfections. But for large things like bass traps and side absorbers, it is better so spend a bit more and get cloth that won't sag over time. Some people even do two layers: one of cheap black cloth to block visibility, then another layer of higher quality acoustic cloth in front, such as those made by Guilford of Maine.

In general it is best to not change the actual mineral wool slab at all: just leave it like it is, as made by the manufacturer, since the published test results are for exactly the way he made it. If you change it in any way, such as gluing something to the surface, or compressing it more, or tearing surface treatment off, then you have a different material with different acoustic characteristics, which might or might not be useful. Most likely not...

So the best idea is just to make a frame that holds the slab snugly, cut holes in the sides of your frame to improve performance, use wire mesh, string or strapping to keep the slab from touching the fabric, and carefully stretch and staple the fabric as recommended by the manufacturer. There are even commercially available plastic clips that keep the fabric under tension permanently, so it can never sag or wrinkle, even if it does stretch. But those add extra cost, and if you work carefully, following the manufacturer's instructions, then you can get very good. long-lasting results yourself, just with a stapler.

- Stuart -

[fitzj]

In all the corners I am stacking triangle pieces of RW3 from floor to ceiling with a shelf in between to take the weigh and stop it falling over. I will then put a cheap material like muslin over the face of all these triangle pieces tacked on to the wall. Then I will put one of the 100 mm deep unit in front of the stack with a space in between and I believe this will give good results in the corners. On the side walls at the left and right listening position and overhead I will put 50 mm absorbers with a 50 mm gap from the wall. The over head one will be adjustable.
On the back wall I will change these to Cylinder shapes with triangle pieces of Rockwool again stacked from floor to ceiling with diffusers on the back wall and ceilings. I am making the frames with a light alloy, powder coated and baked. I hope to use Camira material for the facing of all units as it look nice and available in different colours. Price is not important here. It has to look good, good sound room and last.