Date:         Mon, 8 Jan 2007 14:35:23 -0800
Reply-To:     Nathaniel Poole <npoole@TELUS.NET>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         Nathaniel Poole <npoole@TELUS.NET>
Subject:      Sound insulation -the easy way?
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In response to a recent thread about an expensive new sound insulation for
automobiles, I decided to make up a batch of my own. When we looked at the
ingredients of the product's "magic formula" we found latex, lime, and talc.
It sounded an awful lot like paint with thickeners added. I talked to the
paint guy at home depot, and he said that cellulose is usually used as a
latex thickener. Wallpaper paste is cellulose, but rather pricey in those
small boxes, so I looked further and found bales of cellulose insulation for
$24.00. This is the stuff they blow into attics, basically pulverized
recycled paper. I liked the look of this stuff because it would add a lot of
bulk without weight.

According to the commercial stuff, it's the elasticity of the adhering latex
that dampens the sound, not the mass, unlike the tarry stuff that's used.

I have the 5-gallon buckets of paint in the basement that have been hanging
around forever, with one half full. I really didn't like the colour, but
it'll be covered, so what the hell. I mixed up the paint first and then
started adding the insulation. I probably ended up at 5-1 volume of
insulation before the paint got really thick; stirring 2.5 gals of the stuff
was a bear and I wish I had a paint stirrer for my drill. I wanted it really
thick because I was concerned about slumping on vertical surfaces (and guess
what, I was right.) I should have made it even thicker. As it was I barely
touched the insulation as it is in a compressed bale.

Anyway, the stuff troweled on very well, although I had to redo some areas
where it wanted to slide down. As I worked the paint got thicker and
thicker, which was nice.

As to effect, I can so that so far it is a success. I tested the floor
before I added the goo, and rapping on the floor from underneath with your
head stuck in the footwell, the "clang" was so loud it was borderline
painful. After treatment, it was a dull thud. All the high vibrations were
suppressed. And then the carpet or mat will go on over this stuff, which
will help more.

Now this is with the paint still damp, the final test will be when it dries,
but I don't expect a huge difference. The evaporation of water will mean a
drop in weight, but it's not the mass that's supposed to do this. We'll see.

The big question now is how long it'll take to dry? I've got a heater in
there now.

Pics are up at my site at
http://ca.pg.photos.yahoo.com/ph/kiltman_writer/my_photos