Geno,

> Has anyone tried to spray paint rigid fiberglass. Does it mess up the absorption much? <

Painting rigid fiberglass is not recommended. A better solution is to cover it with an open weave fabric.

--Ethan

I most enthusiastically agree; open weave fabrics seem to be the optimum solution. I've also discovered the critical importance of having ones spouse participate in the selection of the fabric(s). Actually turned out to be quite providential as she knew exactly where to shop once I explained the purpose.

What type of fabric did you purchase and where did you get it? I need 5 yards or more, depends on width.

Dizzie,

> What type of fabric did you purchase and where did you get it? <

This is from my Acoustics FAQ:

Quote:
Nearly any porous fabric is appropriate, and one popular brand is Guilford type FR701. Unfortunately, it's very expensive. One key feature of FR701 is that it's made of polyester so it won't shrink or loosen with changes in humidity when stretched on a frame. But polyester is a common material available in many styles and patterns at any local fabric store. Another feature of FR701 is that it's one of the few commercial fabrics rated to be acoustically transparent. But since you're not using it as speaker grill cloth to place in front of a tweeter, that feature too is not necessary.

Shiny fabrics having a tight weave should be avoided because they reflect higher frequencies. The standard test for acoustic fabric is to hold it to your mouth and try to blow air through it. If you can blow through it easily, it will pass sound into the fiberglass. Burlap and Muslin are two inexpensive options, but nearly any soft fabric will work and also keep the glass fibers safely in place.

--Ethan

Thanks Ethan,

I already have some Guilford samples on order. Not just the FR701 but some of their other offerings as well. Depending on their cost and how I like the looks, I may have to visit my local fabric stores.

At my local shop I already found some plain white (forgot the fabric type) to make mini-curtains for my audio rack. The rack is maple butcher block with solid maple legs. Equipment is all black and it made for a nice appearance except for the schizophrenic spider web of wire. A three amp system will do that quickly. The curtains hang from the rear of each shelf and end just past the top of the equipment but above the inputs/outputs. Dowels are used for the curtain rods.

The acoustic panels I want to cover are RPG Profoam fastened (clear silicone) to coroplast. Those relatively cheap, easy to build panels work very well. I recently built the six frames needed. Only thing left to do is add fabric.

After getting the rack and four matching components (TacT preamp and three amps) I felt a sudden urge to beautify my set up. I wanted it to look as good as it sounds. Do not think I can achieve that but at least I can improve the looks.

> The acoustic panels I want to cover are RPG Profoam fastened (clear silicone) to coroplast. <

If you're going to the trouble to cover panels with cloth, I see no reason to start with expensive foam that's not as good as rigid fiberglass. Just go right to the good stuff.

--Ethan

I would if I was starting again. I made the foam/coroplast panels several years ago before I knew about the rigid fiberglass.

In my opinion, RPG Profoam is advertised falsely. What RPG claims is two inch foam is only one inch of foam in a wavy configuration that is two inches from base to peak. The "panels" are two inches thick but at no point is the actual foam thicker than one inch. Think ~~~~~

> Is it dangerous to leave exposed rigid fiberglass unexposed in the corners of the room? That is, does it become airborne if it's just sitting there? <

Probably not, but nobody I know leaves fiberglass uncovered. The most common covering is open weave fabric of some sort, sometimes with a layer of cotton batting under the fabric.

--Ethan

Those guys are probably well-intentioned, if musguided. For a dose of common sense - and science - see this page:

www.lungusa.org/site/pp.asp?c=dvLUK9O0E&b=35439

Note that this is the American Lung Association's site.

--Ethan

For a sheet of 2" thick rigid fiberglass?

Thanks,
Jim

Jim,

> For a sheet of 2" thick rigid fiberglass? <

Maybe a buck a square foot. It also depends on how much you buy.

--Ethan

I worked for a company that installed site-fabricated acoustical fabric wall & Ceiling systems using mainly rigid fiberglass.

Here is more imformation: www.whisperwalls.com

Quote:
Jim,

> For a sheet of 2" thick rigid fiberglass? <

Maybe a buck a square foot. It also depends on how much you buy.

--Ethan

Hey Ethan,
Thank you for the link. I get this question all the time. Great to give them a link instead.

Glenn

Where can I purchase 4'x8'x1" rigid fiberglass panels?

Quote:
Where can I purchase 4'x8'x1" rigid fiberglass panels?

Raw material or finished panels? If raw, where are you located?

--Ethan

In regards to the painting/fabric covering of fiberglass. My fiance likes to paint and we were thinking that if she could paint a fabric to go over the pannels it would make both of us very happy as each of us would have domain over a given asthetic, visual or acustic. Now we won't be putting any large pastoral scenes up, but more abstract "stuff" with pleasent lines and colors. for the project we have purchased some old burlap coffee sacks, and were planning on painting over them, without putting down a base of white.

what we want to know is weather the paint will destroy the acoustic transparency. It wouldn't completely seal off the fabric, and probably won't cover all of the surface area, but what effect would this have.

oh, and it will be acrylic paints.

cheers!

-Ben

I would think acrylic over gessoed burlap would make the panels rather reflective. For transparency, I'd think you'd be better off with watered down acrylic airbrushed on a much thinner cloth so that the effect is more like printed patterns on bedsheets.

mmm, I was afraid of that, specifically the "gessoed" thing. We were actually thinking about doing the painting without the prior prep, but weren't sure about the whole process. Of course experimentation is fun, but in a directed way.

thanks for the suggestion Jeff

looks like I have some research to do!