I made 4 base traps for our music /TV room. This is a description and some pictures of what they look like. I will take some shots of them with finished with fabric and post them .
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I decided to try making some base traps to see what kind of difference it would make for music and movie watching. The room we listen and watch movies was rather boomy for all low end.
I choose 8lb cotton from Bryan at sensiblesoundsolutions.com he was very helpful with my questions. The cotton comes 5" thick
24" wide and 94" long. It comes 4 pieces to a bundle. A chunk type corner was what I chose to construct so I first had to cut the cotton into 24" squares than cut corner to corner to make 4 triangles approx. 24" on one side and 16" on the other two. The traps I choose to make are 90" tall so I needed to cut 44 triangles (I guessed at 44 because I didn't know how much they would compress once I stacked them that high) for the first 2 traps. I figured I could just cut the cotton with a long razor knife, the type wall paper installers use (the blade can be extended to about 2 1/2"). It didn't make much of a mark on the cotton to my puzzled surprise. I have cut myself so many times just by bumping the blade as they are very sharp. I then decided to try different methods on one end that would be scrap. I tried a fine tooth handsaw made for wood and it did cut it with a bit of pulling on the fibers but did prove to be rather slow. I next decided to try a circular saw with a fine blade( I know this is only cotton fiber that looks like shredded up denim jeans but it is really dense, which is why it works so well I guess). I have used power tool for 30+ yrs. in furniture making so I felt comfortable you may not want to depending on your skill and comfort level. The other option I thought of which Bryan later said he used is an electric carving knife. you know the one in the back of the drawer in the kitchen that always seemed like a good idea but is almost never used. Anyway, once I had cut 44 triangles it was time to build a frame to hold them.
I started by building a triangular frame from 3/4" x 1 1/2" clear pine. It can be purchased at places like Home Depot and Lowes. I cut the front horizontal pieces 23 1/2" long (cut square on the ends) and the other sides 16 1/2" (with a 45 deg. bevel on each end.) The pictures will make this easy to understand. I then cut 3 pieces 90" long for the 3 corners. I put the front face together first with glue and 1 screw in each joint. Use plenty of yellow glue and once it's dry you can handle it with no problem.
After the face is together(you don't have to wait for the glue to set) turn it face down and add the angled pieces flush with the outside edges. If you have ever seen a roof on a building get framed its the same process you are just using tiny rafters and ridge beam.(again the pictures will make more sense of this. Once these were together I let them set over night for the glue to cure.
I stapled a piece of plastic hardware cloth (screen with large holes) on top of the bottom horizontal frame members to support the cotton. Because the cotton does shed a little (although it's not a hazard as fiberglass could be) I chose to wrap the complete chunk before putting it in the frame. I used a material called septic paper. It is used for covering stones in a leech bed of a septic system before the stone is covered with dirt. It is very sheer and tough. I looks like gardeners shade cloth but very fine. It too can be purchased at HD and Lowes for about .03 a sq ft and comes 2',3'and 4'wide. I laid it on a drop cloth and sprayed 3M #77 adhesive on it then set the cotton triangles on it with the 24"face down. I also sprayed a bit on the cotton to hold each piece to the next. Then wrapped the septic paper around it sticking it to the cotton with #77. Then it was a matter of sliding it into the frame. You just need to wiggle it a bit at a time. When most of it is in you can stand it up and gravity will help with the rest. I have not covered them with fabric yet because I spent time this week experimenting with how much reflective surface I wanted to put on the face toward the room.
This is not difficult just takes some patience. If your ability to cut pieces of wood smooth and clean is a problem you can use construction adhesive in a tube instead of yellow glue and it will fill the joints that don't quite fit right as you assemble the frame. You will need to let the construction adhesive set longer than yellow glue, you will know because when you touch it it is hard. Once it's covered with fabric no one will know what it looks like underneath.
I hope I didn't make this to confusing. The pictures are at a yahoo site. I hope the link works. If not I will try another way to link them.
Brad
http://pg.photos.yahoo.com/ph/brock...g.photos.yahoo.com/ph/brock24252425/my_photos
