Brian

 

Your ramp speeds and hold time are important. You have to give the material
time to release water and carbon dioxide. I have used limestone  and not
removed the carbon dioxide from the kiln and had it return back to the
stone. You could have some of this going on in you kiln.  After a few more
tries you should be able to tell the point where you reach red heat. If you
look at the shells it looks like you can see the red right through the
shells. This is hard to understand until you have seen it but at this point
you will have quicklime.

Do you have a kiln sitter on your lab kiln? If you do let me know and I will
get the ramp and temp settings for you.

 

Ken

 

From: The Listserv that makes holes in Manhattan schist for free!
[mailto:[log in to unmask]] On Behalf Of Brian Robinson
Sent: Sunday, April 29, 2007 5:24 PM
To: [log in to unmask]
Subject: Re: [BP] Lime burn part two results

 

Ken, 

 

Thanks for the advice. I think we will incorporate several of your
suggestions next time around. 

 

I went to the kiln to get the shells out today. I could tell that they were
underburned when I took them out. They were too heavy and not flaky enough.
Our first burn a couple of weeks ago produced some unevenly burned shell
that had some good stuff in it that was extremely light and turned to powder
easily. Even though the first batch from a few weeks ago was partially air
slaked overnight in a light rain it was still moderately reactive the next
day in the lab. What I pulled out of our kiln today was still rather chunky.
I added some water in a quick and dirty test and nothing happened. I stuck
the thermometer in and could not see any noticeable rise in temperature over
almost an hour. I will pulverize some in the lab and try again. If nothing
happens I might try to make pancake batter from the rest or try to reburn it
in a future kiln. 

 

I have some well burned quicklime oyster shell from Virginia Lime Works in
the lab. I am going to crush and weigh that product and compare it to my
stuff to see what the weight difference is. That should give me a goal to
shoot for.        

The bottom line is that it appears that we have not burned hot enough for
long enough yet. It takes a couple of hours to goose the kiln up to the
right temp range and we were on the extreme low end of the acceptible time
frame for a successful burn. Round three will happen in a couple of weeks
with the fire brick incorporated into the improved kiln design. Soon, it
will be too hot to work with kilns for a while. It was in the 90's here
yesterday. I might take the show on the road to New York when I am at Mt.
Lebanon for the summer. 

 

I got some great photos and video yesterday. I will post the urls for them
as soon as I get them posted tonight. 

 

Thanks again for the help,

 

Brian          

-- To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
http://listserv.icors.org/archives/bullamanka-pinheads.html 


--
To terminate puerile preservation prattling among pals and the
uncoffee-ed, or to change your settings, go to:
<http://listserv.icors.org/archives/bullamanka-pinheads.html>