Fiberglass pipe cover

arthurs · « **on:** 1 Jan 2007, 04:06 am »

I have gained access to a bunch of Johns Manville fiberglass pipe covers in 9", 16" and 22" diameters that have 1.5" thick walls.

I've seen the diy sites for making traps out of these, looks pretty straight forward. Any additional advice from the experts here? Does the foil paper wrap on them work as a reflective side? Should they be stuffed with anything before I cap the ends and wrap them in fabric?

I have enough to cover all my corners floor to ceiling and a couple columns along all walls, also floor to ceiling...

Thanks for any advice or guidance...

Ethan Winer · « **Reply #1 on:** 1 Jan 2007, 02:42 pm »

Quote from: arthurs on 1 Jan 2007, 04:06 am

Does the foil paper wrap on them work as a reflective side? Should they be stuffed with anything before I cap the ends and wrap them in fabric?

A paper wrap might increase bass absorption a bit, and will also reduce absorption at mid and high frequencies. The first is always useful, the second depends on what your room needs. Either way, if you stuff the center with fluffy fiberglass it will absorb even better.

Also, there is no need to cap the ends, and in fact that can only reduce absorption.

--Ethan

TomS · « **Reply #2 on:** 1 Jan 2007, 02:52 pm »

Chris at Teres has a nice DIY on using pipe wraps for building tube traps here

http://teresaudio.com/haven/traps/traps.html

arthurs · « **Reply #3 on:** 1 Jan 2007, 03:18 pm »

Thanks Ethan and Tom.

Ethan, I suspected your suggestion on capping them, but can't quite figure out how to stuff them or wrap them in fabric without capping them (to hold the stuffing in or provide a surface to staple the cloth to) ...any thoughts?

bpape · « **Reply #4 on:** 1 Jan 2007, 03:43 pm »

You can just stuff them with standard fiberglass insulation. For wrapping purposes, you can make the caps but use a Jasper jig to route out the center so it's just maybe 1" all around with a hole in the center.

As for the facing, a neat trick is to remove it from half of the cyliner so 180 degrees is faced and the other 180 degrees is unfaced. Mark the center of the facing somehow so after it's wrapped you'll know where it is. This allows you to turn them as the room and placement require to provide some additional flexibility and control of where you're getting reflection of the highs and where you're getting absorbtion. Some existing tube type commercially available treatments use this method.

Good luck.

Bryan

arthurs · « **Reply #5 on:** 1 Jan 2007, 03:54 pm »

Thanks Bryan, it was my plan to leave 180 covered and 180 not. After looking at the Teres site, do you think the foil lined paper does the trick for reflective or do I need to remove it and use a plastic film like he recommends?

I was also thinking there must be some type of adhesive I can use to fix the cloth wrap to them so there's no need to do any type of top, just a bse for the sections that will sit on the floor....

bpape · « **Reply #6 on:** 1 Jan 2007, 04:13 pm »

If you remove the foil and go with a thinner plastic, it will provide less membrane effect and allow more upper mid/hf absorbtion even on the sides that are covered.

If you glue the cloth directly to it, you'll damp a lot of the membrane action from the foil/plastic - though with the right material, you'll still maintain most of the mid/hf reflectivity. All depends on what you need.

Bryan

Rob Babcock · « **Reply #7 on:** 2 Jan 2007, 12:25 am »

I definately wouldn't be comfortable with raw glass stuffed into a tube and left uncapped.

Fiberglass is carcinagenic and very dangerous to your lungs. I'll take a little less absorbtion to keep it safe.

arthurs · « **Reply #8 on:** 2 Jan 2007, 01:11 am »

Quote from: Rob Babcock on 2 Jan 2007, 12:25 am

I definately wouldn't be comfortable with raw glass stuffed into a tube and left uncapped. Fiberglass is carcinagenic and very dangerous to your lungs. I'll take a little less absorbtion to keep it safe.

Fair point Rob, I'll find some way to cover the top tube so no fiberglass floats out....

bpape · « **Reply #9 on:** 2 Jan 2007, 01:13 am »

Stretching a little bit of thin plastic over the tops will take care of that with no problem without sacrificing any performance in the bottom end. Also, the fiberglass inside without caps is no different than the 180 degrees of the perimeter without a facing directly covered with cloth. And just for general info, while fiberglass is certainly itchy and no fun to handle, it is not a carcinogen.

Bryan

Daygloworange · « **Reply #10 on:** 2 Jan 2007, 01:18 am »

arthurs,

You could search around and find materials like what they use for dust collectors. Some of them go down to very small micron filtration. You could use that to envelope the tubes once they're stuffed. There are probably some outfits that could sew them for your given diameter and length. You could always dye them after to match your color scheme. Check it out. Do a search on dust collectors.

Cheers

arthurs · « **Reply #11 on:** 2 Jan 2007, 01:26 am »

Thanks Denny, I'll check it out.

Daygloworange · « **Reply #12 on:** 2 Jan 2007, 01:46 am »

Cheers

Rob Babcock · « **Reply #13 on:** 2 Jan 2007, 03:28 am »

Quote from: bpape on 2 Jan 2007, 01:13 am

Stretching a little bit of thin plastic over the tops will take care of that with no problem without sacrificing any performance in the bottom end. Also, the fiberglass inside without caps is no different than the 180 degrees of the perimeter without a facing directly covered with cloth. And just for general info, while fiberglass is certainly itchy and no fun to handle, it is not a carcinogen.

Bryan

Ooops, you're right. I was somehow thinking of asbestos.

I still think keeping the fibres in is a good idea.

bpape · « **Reply #14 on:** 2 Jan 2007, 04:05 am »

Agreed. It's definitely wise to use a respirator or mask when working with it - especially if you do it all the time. Realistically, the amount of fiberglass in the air from a static sitting tube with a cloth covering is basically zero though. It's when you disturb or cut it that it becomes an issue.

All I was trying to do was clarify and help dispell the myth that fiberglass and mineral wool are carcinogenic. Heaven knows everything else in the world is supposed to cause cancer.

Bryan

arthurs · « **Reply #15 on:** 2 Jan 2007, 04:17 am »

Since these will end up being 3 sections high, I'm going to have a solid bottom for the floor, connect the middle two sections with some type of finishing wrap (likely a 2.5" vinyl slat from a vertical blind) and finish the open top of the highest cylinder with whatever fabric I end up with, should keep anything from floating out on the off chance it wants to....

Daygloworange · « **Reply #16 on:** 2 Jan 2007, 04:18 am »

It's worth mentioning.....don't need people in a panic. There are much worse air pollutants in the average home that never hit the radar.

Cheers

Ethan Winer · « **Reply #17 on:** 2 Jan 2007, 04:45 pm »

Art,

> can't quite figure out how to stuff them or wrap them in fabric without capping them (to hold the stuffing in or provide a surface to staple the cloth to) ...any thoughts? <

I meant only to avoid a rigid cap made of wood or MDF, as those plans often show. You can certainly cover the end openings with fabric, or fabric over cotton batting.

--Ethan

Red Dragon Audio · « **Reply #18 on:** 2 Jan 2007, 07:37 pm »

Perforated Metal.

Cut perforated metal into a circle to fit the end of the pipe.
Pack your pipe.

(if you don't like cheap pink stuff - then you can always do polyfill I guess or wool).
Use liquid nails to glue perforated metal circles in place.

Once liquid nails has dried, sand down to smooth finish.
Cover with fabric.

arthurs · « **Reply #19 on:** 2 Jan 2007, 07:44 pm »

Good suggestion Ryan....I'm probably going to go with something simple like that, but cut it, wrap it in fabric and then just glue it to the top. The shortest tube I'll have is going to be 7' the average will be 9' so what the top looks like aesthetically isn't that critical, no one will see it....