Firebrick

[Ben Discoe]

Responding to my own message with more info:

"Found some firebricks in Hilo at the "Fireplace and Home Center". They
just got a shipment of 500 in. If you buy a large quantity like 200 brick
they cost $3.99 a pc. Call Mel or Mary. (808) 961-5646."

Apparently these bricks are popular for home-made wood-fired ovens. Too
expensive to make a whole charcoal kiln out of them, but perhaps if you
build carefully to use them only in the spots that receives the most heat.
I've ordered some to experiment with. I know Josiah might say, why use
expensive brick when you can use a simple unlined hole in the ground, but I
am still quite attached to being able to scoop out my char quickly and
cleanly without any soil or rocks mixed into it, especially rocks as they
make trouble for grinding.

I've also got some possibly-crazy ideas about baking my own bricks from the
local clay-like soils of Hamakua. Presuming I can determine the right
amount of sand to add to keep them from cracking to pieces, then they could
form the clean walls of an inexpensive pit. Perhaps they could even be
baked in the pit itself, then once hardened they take the place of the
fragile CMUs or expensive imported firebrick.

-Ben

> -----Original Message-----
> From: Ben Discoe
> Sent: Thursday, August 09, 2012 9:27 AM
> To: biochar...@googlegroups.com
> Subject: Re: Biochar Bob goes to Hawaii
>
> ...
>
> I'm still looking for fire brick anywhere in the state of Hawaii. It
seems hard
> to find even regular brick, let alone higher-temperature brick.

[Bobby Grimes]

All sounds good. I like the idea of bricks from Hamakua Clays or possibly another BI Spot?

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[Ben Discoe]

I know for sure that on my land in Ahualoa, if you dig away the top foot of
topsoil, what's underneath is frequently sticky, slippery clay. I suspect
this is true for much of Hamakua. You can play with it in your hands and it
feels a lot like pottery clay. If I remember correctly, Jonathan Deenik
told us that our soils here were formed from weathering of aluminum-rich
volcanic ash - a huge ash explosion of Mauna Kea many thousands of years ago
formed most of the soil from Hilo to Waimea. Whereas the "good" clay that
potters use is from glaciers scraping rocks together, which is probably
entirely different under a microscope. So, i have basically no idea what
will happen if you bake the Hawaiian clay-like soil, or how much drying it
would need, or what temperature might work. Will find out soon!

As far as I know, the native Hawaiians didn't make pottery. One online
reference says "..pottery-making did not persist in most of Polynesia,
mainly due to the lack of suitable clay on small islands", another says
"Polynesian peoples were not potters because wood had become the preferred
material for bowls and jars." So, our 'clay' may not work for general
pottery, but ... hopefully well enough for simple building blocks.

-Ben

[m a]

I live on hamakua and i tried making my own clay for sculpting. no
luck trying several times using the separation method. not enough clay
in the soil. it looks sticky and feels sticky, just not enough clay to
actually make something usable.

[Josiah Hunt]

Hi Ben,

For our Kilns (built by Bob Ely) we have successfully created fire
brick type stuff. The basic recipe is :

Find the most porous cinder you can find (I can help), mix with
hawaiian cement, harden and dry. Bake at lower temps before full
going full tilt, the moisture leaving can do a lot of damage.

These work well enough for thermal purposes, though are not as
structurally tough as other options. Another trick learned from a
pottery kiln builder - cheap ceramic tiles. Any basic ceramic tile
from your local hardware store was fired at high temperatures, can
easily withstand them again, and does a fairly good job keeping heat
on one side.

Hope this has been helpful,

- Josiah

[Bobby Grimes]

Thanks Josiah, Bobby G

Bobby Grimes
PO Box 107
Paauilo, HI. 96776

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