[Sca-cooks] Charcoal forge suggestion ;-)

[Jeff Gedney]

The cuplrit in this case was moisture... 
since you were unevenly heating the terra cotta pottery (which is usually unfired clay) any moisture in the aggregate will go to steam unevenly and the internal pressure, along with the thermal stress, will crack such a pot every time. 

Try removing the moisture by placing the pottery in a 220 degree oven overnight. then in the morning turn the heat up to 500 degrees for a couple of hours to "set" the pot. 
That should manage to protect your pot soemwhat. 
(it still neads to be heated evenly and slowly or thermal stress will crack it, but it helps on the moisture front) 
The problem is going to be that if the pot is heated evenly enough to prevent thermal stress cracking it, it will also be hot enough on the bottom to damage what it is set on anyway, so perhaps your best bet is to use a pot in conjunction with an insulating surface, such as a sacrifical wood plank, or anothe clay tile, or a metal trivet. 

Perhaps a better alternative is to line the pot with an inch or so of slighly moist sand. 


Capt Elias

--------------------------------------------------------------
If you want to build a ship, don't drum up the men to gather 
wood, divide the work, and give orders.  Instead, teach them
to yearn for the vast and endless sea. 
  - Antoine de Saint Exupery 




---------- Original Message ----------------------------------
From: Stefan li Rous <StefanliRous at austin.rr.com>
Reply-To: Cooks within the SCA <sca-cooks at ansteorra.org>
Date:  Mon, 18 Oct 2004 00:41:07 -0500

>Phlip replied to me with:
>> > I remember trying to use a clay flower pot saucer to hold charcoal
>> > for a period pewter casting demo at an event but the heat cracked
>> > it. And I only used a few chunks of hardwood charcoal. I think part
>> > of my problem was not using enough since I wasn't getting enough
>> > heat. I thought I needed a bellows then, but I think just more
>> > charcoal. And that might have reduced problems with expansion and
>> > the clay saucer breaking, but I think I'll go with a different
>> > container next time, anyway.
>> >
>> > Stefan
>>
>> Stefan,
>>
>> Of COURSE it cracked- a flower pot just isn't up to the temperatures 
>> you
>> generate when you're operating a forge.
>I wasn't forging. This was simply a pile of lit charcoal upon which to 
>set my thin, large spoon to melt pewter so I could pour it into my 
>soapstone molds. I was in fact having trouble getting enough heat to 
>melt the pewter, so that it would pour easily into the mold. It was 
>pretty thick. Not like what I was used to getting in my electric 
>melting pot. Which is why I originally thought I needed a bellows. I 
>was trying to do this demo in a period-like way instead of using my 
>modern melting pot. The clay saucer was also there to protect the 
>wooden picnic table I was doing this on. I also had a piece of metal 
>and an piece of plywood between it and the picnic table.
>
>That night I was given my Sable Thistle (the AoA level Ansteorran Arts 
>and Sciences award) for my pewter casting. This came as a total 
>surprise since I had been doing the Florilegium for a number of years 
>before that, and when I got called into court, assumed that that was 
>the reason. So some folks, or at least the king, must have liked the 
>demo and the stuff I had been doing.
>
>Thanks for the rest of the forge info. Yes, I had been told that the 
>kitty litter clay would have to be periodically reapplied to the grill. 
>There is some info in the Florilegium on making forges, and much, much 
>more out there on the web. I guess I'm going to have to do some more 
>reviewing and research before I actually try to make my forge. Because 
>of the amount of time needed on the Florilegium and other things, I am 
>probably not going to use the forge for anything but occasional 
>projects.
>
>Stefan
>--------
>THLord Stefan li Rous    Barony of Bryn Gwlad    Kingdom of Ansteorra
>    Mark S. Harris           Austin, Texas          
>StefanliRous at austin.rr.com
>**** See Stefan's Florilegium files at:  http://www.florilegium.org ****
>
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