Soundproofing by Slurryguy

As found on the papercreters Yahoo! Group:

I'll toss this custom recipe that I'm designing off the top of my
head as I type this message. I've never tested it exactly this way,
but I'm reasonably confident it would work well for this
application. It should be very high insulating and good sound
supression and low flamability/smolderability. I'll list quantities
appropriate for a 200gal tow mixer.

  • 60lbs newsprint (I think newsprint will be better than magazine paper for this particular purpose.)
  • Half bag of cement. (47lbs or so)
  • 6 lbs laundry borax.
  • 150 gal water. (Enough water to fill the tow mixer, but not so much to have it slop over the side while mixing.)

Pulp mixture thoroughly.
Pour into mold or forms.
Allow to drain for 5 minutes.
Compress drained slurry into form.
Let sit for an hour.
Remove form.
Allow to dry for 3-4 weeks, depending upon the weather.
Install in the chamber.

The mix will need to be installed several inches thick. 2 or 3
inches thick will deaden a little sound. 6 inches will probably be
kinda okay. A foot thick would be good. Two feet thick would be
great. (I'm assuming it's going to be a reasonably small room.)

Don't forget to cover the floor, the ceiling, the door, and the
windows. The doorway may require some kind of removable panel or a
2nd door.

This papercrete is NOT going to be a very strong mix. It will be
fairly weak compared to many other papercrete recipies, but it's not
designed to support structural loads, so it shouldn't matter much.
It should be strong enough to support its own weight, but that's
about all. Don't expect it to hold up a roof. It should be very
very easy to cut the dry blocks with a saw.

The high borax content should keep the flamability/smolderabilty very
very low, but this mix should not be considered completely fireproof.

I repeat. I haven't tried this mix. I haven't tested this mix.
This is something I just thought up off the top of my head based upon
my experience testing various mixes and logic about what makes a good
sound barrier. It is possible my guesses could be incorrect about
how well this mix will perform. I recommend that anyone considering
this mix test it in a small quantity before trying to use it. If it
doesn't work the way you like, don't use it. Be sure to put a torch
to a dry test block to verify that it won't be a firetrap. STAY SAFE.

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