[papercreters] Re: Using papercrete to insulate the chimney in a rocket mass heater

I'm a little late responding to this post, but I'll toss in my 2 cents.

I do not recommend using paper"crete" as the insulation in the riser in a rocket stove/heater.

The whole point of the rocket stove is to insulate the combustion chamber so that extremely high temperatures will be reached. Easily over 1000 deg F. This allows far more efficient combustion. That's why there's essentially no smoke from a well built rocket stove. Smoke is simply wood particles that were not completely burned.

Cement, even under the best of circumstances does not handle those kinds of high temperatures well, especially repeatedly over an extended period of time.

What you'll eventually have is the paper in the papercrete burned up, and the cement breaking down and turning to dust in the bottom of the riser of your rocket stove/heater. How fast that happens depends on many factors that would be a waste of time and typing to go into here.




As an alternative, I highly recommend using molded, very well dried, and carefully fired PAPERCLAY. This will allow you to make a genuine insulating refractory ceramic that can handle the super high temperatures you want your rocket stove/heater to burn at.

If you choose, paper pulp can easily replace the sawdust as described in the following video. I realize this is a video for a cooking stove, but the description about how to make the sawdust clay insulation brick appears to be exactly what you are looking for.
http://www.youtube.com/watch?v=YIMi0DVDvqw

If you want to substitute paper pulp for the sawdust it will work fine. Probably even better because the particle sizes for the paper particles will be smaller than most sawdust particles, yielding a better ceramic insulation. Some experimentation to get the quantities of paper and clay just right are to be expected. Try several small experiments using different ratios to see what works best for you.

I love papercrete. It's amazing stuff, but it is not appropriate for every application.



--- In papercreters@yahoogroups.com, "oystein_tandberg" <oystein_tandberg@...> wrote:
>
> Hi!
> I was wondering if anyone has any experience in using papercrete to insulate chimneys? I'm planning to make a rocket mass heater, and I see most people use perlite, but perlite is very expensive here, so I was thinking using papercrete instead – ideas anyone?
> Best regards
>




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