[Stoves] Grass Fireballs burn cleaner than wood

[Kevin Chisholm]

Dear Crispin

There are two mechanisms involved:: 1: Crushing, and 2: Grinding.

If the mill is operated primarily in the cataracting mode, then the 
particles will be crushed as the stone falls on them. However, very soon the 
sharp edges will be worn off the stones, and they will become rounded.

The slurry sticking to the stones is abraded by other stones rubbing against 
them, to yield a fine ground product.

I think you would be just as far ahead by starting with rounded pebbles. It 
is very important that the chosen rocks or pebbles be both abrasion 
resistant and tough, so that the media does not wear away, or shatter.

Best wishes,

Kevin
----- Original Message ----- 
From: "Crispin Pemberton-Pigott" <crispinpigott at gmail.com>
To: "Stoves" <stoves at listserv.repp.org>
Sent: Thursday, December 28, 2006 11:32 PM
Subject: Re: [Stoves] Grass Fireballs burn cleaner than wood


> Dear Jeff
>
> I think ordinary granite crushed stove would be perfect.  Rounded gravel
> from morains (etc) is not at all the right shape.
>
> The hardness of stove put onto tar roads is (Treton Impact Value) between 
> 12
> and 20.  If you have a stone good enough to put onto a tar surface, and it
> was crushed from larger rock, it is going to do a pretty good job 
> grinding.
>
> Regards
> Crispin
>
>
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