[Stoves] possible improvements in molding holes in your ingenious clay disk grate

[K McLean]

Richard,

Thank you for your comments.

I'm not sure what got to you in the forwarding process.  Here is a link to
the video of the woman making the grate:
https://drive.google.com/file/d/1PK-ydOdtbUZM_efWWNtkaw1UiFeYINIu/view?usp=sharing.
She isn't an "artisan".  We give out the metal molds.  Any woman can use
the metal mold to make the clay grates with a few minutes of instruction.
She can then make and sell the clay grates.

That is the entire production process, all 1:12 of it.  The grate dries and
is fired in a kiln.  It's explained in greater detail in our Cookstoves
Overview:
https://docs.google.com/document/d/1ZryS7gQ1q3zKLZPM2KcXdtIHbOYQp4PbloPqMvrlZ5Y/edit?usp=sharing

She can probably make your conical holes by fixing tip of the stick in the
ground and swirling the top of the stick in wide circles.  We'll test
this.  We are also testing various hole sizes and number of holes.

I agree that a powerful press is unnecessary.

Thank you,
Kevin

*Kevin McLean, President*
*Sun24*

*https://sun24.solar <https://sun24.solar>*
*Tampa, Florida, USA*
*+1 (813) 505-3340*







On Sat, Dec 15, 2018 at 5:08 PM Richard Stanley <rstanley at legacyfound.org>
wrote:

> Kevin,
>
> Crispin suggested I look at your video but I could not find any ref. in
> it  to the production process used for the grates, so forgive me if I am
> completely out of turn in making the following observations.
>
> Our basic compound lever press would easily work for your needs but I
> think it would be a bit of over kill. Our "mini bryant" press generates
> about one ton of force which would seem like much more than you need to
> punch (??) 1 dozen odd holes thru a (??) 1" thick wet with wet saturated
> clay.  A simple single lever press would be (probably already is sufficient
> or ??
> Again,  I do not have any idea about your molding or pressing process so I
> may be entirely out of turn here.
>
> My second unsolicited comment is that it will be far easier to make
> slightly conical holes for your grates ( rather than your existing
> cylindrical ones) because;
>
> 1) it is far easier to remove a conical piston then a cylindrical one in
> the molding process, as the piston(s) will tend to break free upon
> retraction, rather than dragging back thru the clay disk.
> and, far more more important to the user;
>
> 2) A grate inserted in a stove three stone or otherwise, with  its such
> tapered holes tapering in  towards  the top / out towards the bottom, will
> tend  to minimize ash clogging /ease ash clean out. I noticed with Hugh's
> stoves in Kenya, where he began in the late 70's and again in Mali ten
> years on, that his cylindrical formed stove holes tended to clog up from
> time to time / locale to locale Of course the perfectly dry hot burning
> wood or fuel briquette will leave little   solid carbon behind and bridging
> would be minimised, but this is of course not always the case in reality,
> eh? The bits that would tend to bridge and clog a cylindrical hole tend to
> fall through the suggested tapered hole of your grate.
>
> The idea of making this is ingenious by the way; highly adaptable easily
> reproduced y local artisans and effective. Congradulations on that !
>
> Richard Stanley
> www.legacyfound.org
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