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Old 11-24-2008, 09:13 PM   #23
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Join Date: Aug 2006
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Part VI - How to treat a typical residential space for less than $100 in a single day.

Materials needed:

- 2'x4' Rigid fiberglass insulation panels (aka Owens-Corning 703 or 705, aka rockwool, aka mineral wool, aka mineral board, aka ductboard). This is the key ingredient and is NOT available at Home Depot, Lowes, or conventional hardware stores. You have to order it from insulation companies or industrial supply houses. Denser and thicker is better, but if you're doing corner traps with air gaps behind, pretty much any of it is fine. In the US, a company called SPI (Specialty Products Inc) has a lot of semi-retail branches that sell 2"x2'x4' panels for around $40 per bundle of 6. Check the yellow pages and make a couple calls.

Total $40

- Fabric. this is important to wrap the panels in, since you don't want mineral fibers floating around the room. Pretty much anything is fine. Burlap is great. If you can blow through it easily, it's acoustically transparent, but that hardly matters until you get to leather or something. Fabric typically comes from rolls that are about 2 yards (6 feet) wide. 36 linear yards gives you room to make mistakes. Ikea sells plain beige light canvas for 99c per yard. I'm guessing it's similar in metric countries.

Total $76

- Big wire ties (aka zip ties). Anyone used to coiling wire should be familiar with these. They are the same as the plastic zip-tie handcuffs you see on TV. They are great for hanging stuff because they are super-easy to adjust. Buy 50 or more of the longest ones you can find. you'll need four per panel (24), but it's better to have extra. Figure $10.

Total $86

- Fender washers. Four per panel for a total of 24. Purely for strain relief so you can use duct tape or anything else if you feel like it. Under $3.00

Total $89

- Glue gun. Whatever. You don't actually need a glue gun, you just need some way to affix the fabric to itself. A stapler can work, too. If you're good at sewing or something, that's better. If not, a glue gun is super-easy way to just shove it all together and it doesn't matter how messy the back side is. Buy the cheapest one-- there's nothing heavy-duty about this job. $7

Total $96

- Eye hooks. You need 12 to hang six panels, but buy 20. At 10c apiece.

Total $98

Stuff you should already have:

Tape Measure
Something to poke through fiberglass with (screwdriver or chopstick is good)

So now that you have all your materials, put on a pair of gloves and some work clothes (you are about to handle fiberglass, and it's wicked itchy if it touches skin, so wear long sleeves and prepare to do laundry after).

Start with just one panel so you get the hang of it, then you can go production-line on the next five.

1. Measure spots for 4 holes about 1/3 lengthwise and about 1/3 crosswise on the panel. punch through the panel with a poker. Small phillips screwdriver or chopstick works great. This is not precision work, just get them roughly centered, or at least far enough apart so that there is enough fiberglass so they won't rip through.

2. pick one side of the panel to be the clean "front." Through the back, stick one of the zip ties through, then put two fender washers for strain relief on the front side, then loop the wire tie back through the other hole and loop it through to the bare minimum to fix the loop. There should be a generous loop in back left over. One fender washer should fall flat against each hole on the front, in case you are not smart enough to figure that out.

3. Spread out a generous stretch of fabric and set the panel, front-side-down, upon it. Pull the fabric up and and wrap it like a present, hacking it so the zip tie loops stick through, and seal it up with the glue gun. Nobody is ever going to see anything on this side, so don't worry about being messy. Have a beer or three.

4. Back in your control room, pick the spot for your first panel, and screw two eye hooks into the ceiling, approximately 6" from the wall and spaced about the same width as your zip ties are, maybe leaning slightly towards the corner so you get a good seal (this does not have to be precision work-- the adjustable zip ties will let you finalize it by eyeball).

5. Loop two new zipties through the eyehooks, but don't connect them. Lift up the panel and loop the eyehook-hanging ziptie closest to the corner through the ziptie that's already glued into the panel. Zip it just enough to close the loop (don't pull it tight against the ceiling just yet). Do the same with the second ziptie and then step back and take a look. There should be some slack. If your zipties don't easily reach all the way through the loop, use a third ziptie in the middle (like a chain-- eyehook ziptie, joiner ziptie, panel ziptie)

6. Reach under and pull each side tight just until the panel is touching both the ceiling and the wall. Pull the ties that are run through the eyehooks, not the ties that are run through the panels (this way you can re-use the panels). Don't over-tighten or fold the panel up into the corner, just get it more or less even with both the ceiling and the wall. This can be an awkward job, reaching behind and under the panels, but it's not complicated. Aesthetics are a bigger consideration than acoustics at this point. Keep in mind that wrinkles in the fabric will tend to even out over time, assuming your gluing was not *too* drunken.

You're done! Repeat with the other five panels, sticking them wherever you can, keeping in mind that three-way corners are best. The before-and-after difference will be HUGE in a typical residential room.

Last edited by yep; 11-24-2008 at 09:27 PM.
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