Brian:
Not sure I understand the process well enough, even to specify for a restoration project, but I made notes at a lecture by Jimmy Price. He described a traditional burning rick observed in a remote location I didn't note, as follows:
Traditional “rick” to burn lime; circle of logs, center open with a stake; tie light wood to stage as a “funnel” for the burn; mix green and dry wood packed around, spokes pointed down to center; funnel sticks through at top; stones set on top; hot coals in center to ignite the rick; burns down through entire rick; stones roll toward center;
He also said that the temperature must be between 1250 and 2150 degrees, or you don't get lime. And, he said that burning with wood creates a moist heat, with steam escaping from the burning wood.
Does that jive with your observations at the NPS demo? Some of your description seems to be consistent with what Jimmy described, although the efficiency is a good question, when a lot of lime would have been needed for a larger structure. Perhaps they were selective with its use, like only for a chimney or foundation, where mortar is critical.
Of course, the Price lecture did not even consider the tabby process, focusing only on the use of limestone sources to create lime.
Ilene R. Tyler, FAIA
QUINN EVANS | ARCHITECTS
219 1/2 N. Main Street
Ann Arbor, MI 48104
ph: 734 663-5888
fx: 734 663-5044
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From: Yes, we set off an A-bomb but we are really sorry about it. on behalf of BULLAMANKA-PINHEADS automatic digest system
Sent: Sun 11/12/2006 3:00 AM
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Subject: BULLAMANKA-PINHEADS Digest - 9 Nov 2006 to 12 Nov 2006 (#2006-230)
There is 1 message totalling 304 lines in this issue.
Topics of the day:
1. Oyster shell lime burn issues
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Date: Sat, 11 Nov 2006 21:29:11 +0000
From: Brian Robinson <[log in to unmask]>
Subject: Oyster shell lime burn issues
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Oyster burn issues
Just got back from watching a rick with oyster shell lime burn at =
Ashantilly in Darien=2C Georgia=2E I have several issues with the proces=
s and also several questions=2E =
For those of you not familiar with this historic process=2C a series of =
pine logs are stacked and oyster shells are placed inside=2E The entire =
mass is set on fire with the goal of creating quicklime which will then =
be used for a variety of traditional lime based construction products in=
cluding stucco=2C whitewash=2C lime mortar=2C and plaster=2E Photos and =
video are available at http=3A//www=2Emyspace=2Ecom/professor=5Frobinson=
=2E =
I tend to discount the current conventional wisdom that this rick burn p=
rocess was the main method of producing quick lime in the southern US fr=
om 1730 - 1800=2E I see the entire process as rather unscientific and ex=
tremely labor intensive=2E The process I saw today was conducted by a re=
tired =
NPS employee from Fort Frederica=2C a 1736 tabby fort located on St=2E S=
imons Island=2C GA=2E He was not very receptive to my suggestion that ot=
her methods could have been employed in the creation of quicklime in col=
onial Georgia=2E Despite my diplomatic inquiry=2C I quickly realized tha=
t there was little information to be gathered from this resource so I se=
ttled down to experience the process as it was being presented=2E =
First=2C this was only a =22demonstration=22 of the process=2E There was=
little pretense that the material generated from this process would be =
usable=2E I question doing a less than accurate interpretive demonstrati=
on when only a little additional effort could result in something much m=
ore worthwhile and accurate=2E One of the first problems I noticed was t=
hat the oyster shells he used were fresh=2E These oysters had only been =
eaten a few days ago=2E It is my understanding that oyster shells would =
typically be extracted from prehistoric shell =
middens in order to gather material that had been completely leached of =
salts=2E New oyster shells would have a high salt content=2E I assume th=
at any residual salts would be transfered to the mortar leading to poten=
tial future problems with mortar performance=2E Is this accurate=3F
Second=2C the entire structure burned to the ground in only an hour=2E I=
t burned with a tremendously intense heat for the first 15-20 minutes=2E=
The heat was so extreme that standing =
within 20 feet of the rick was impossible=2E Anyone with any experience =
with pine logs know that they burn hot and fast=2E Oyster shell fragment=
s started spitting out of the fire after about 10 minutes=2E How can a s=
teady temperature be achieved with such a process=3F There was no way to=
regulate the oxygen flow to the conflagration=2E It was essentially an =
uncontrollable fire=2E Why were the shells spitting out of the fire=3F W=
as this the result of residual moisture in the logs and the shells escap=
ing=3F Were the shells actually burning and rehydrating (with this resid=
ual steam) within the initial 10-15 minute span=3F =
Within 1=2E5 hours the entire pile had turned to ash with the white oyst=
er shells still visible in the glowing ash pile=2E Once everything cools=
=2C how do you =
separate the shells (quicklime) from the ash=3F Can you just mix up the =
mess together in a hole and make it work=3F Shouldn=27t the ash be separ=
ated=3F Aren=27t the shells on top exposed to cooler temperatures than t=
he shells inside the pile=3F How can you ensure a consistent quality of =
material=3F Should the entire mass be stirred regularly to even out the =
heat=3F Is it possible that the heat would be far too intense to create =
an effective result=3F =
I estimate that 15-20 gallons of oyster shells were used in this process=
=2E I would guess that=2C at best=2C only 5 gallons of quicklime would r=
esult from this burn=2E It seems that cutting and stacking 2 dozen logs =
5 feet long into a rick roughly 1=2E5 meters square is a lot of work to =
only create 5 gallons of quicklime=2E To construct a house the size of =
Ashantilly (3 stories=2C approx 4000 sq feet=2E walls 18=22 thick) using=
this process would require the gathering and burning of an entire fores=
t of trees=2E =
Gerard Lynch=2C our mason friend from the UK=2C has clearly demonstrated=
that with only 300-400 bricks and a little mortar=2C a small lime =
kiln can be constructed and fired up in about 8 hours=2E This kiln can =
remain on site and be reused over and over to burn calcium carbonate=2E =
His kiln burns at a managable temperature and the heat can be regulated =
by increasing or decreasing airflow and fuel into the kiln=2E At the end=
of the process the kiln can be deconstructed and reassembled on the nex=
t construction site=2E His kiln uses traditional material and techniques=
=2E It appears to me that it would be much more sensible to have a maste=
r mason build a temporary kiln on a construction site rather than fell a=
nd stack dozens of trees to achieve inconsistent results=2E The argument=
that the NPS guy gave was that there were no bricks available during th=
is period=2E The tabby c=2E 1741 Horton House located only 25 miles to =
the south of Ashantilly had bricks in the foundation that were robbed ou=
t in the post civil war era=2E Evidence of these bricks are still visibl=
e at the site so that argument does not hold water=2E Plus we all know t=
hat small loads of bricks and lime putty or dry hydrate would have been =
easily transportable by ship=2E =
The more I learn about traditional building practices the more I underst=
and that past practitioners focused on processes that were based on comm=
on sense practices that were as straighforward and simple as possible=2E=
Labor was precious and life was hard enough without doing stupid things=
to make construction difficult=2E I plan to return to the rick burn sit=
e tomorrow to gather some of the burned shells and take them to school o=
n Monday=2E We will attempt to hydrate the material and see what we get=2E=
The students will enjoy watching the material boil if nothing else=2E =
Any comments or thoughts about this process would be appreciated=2E I am=
not a lime expert=2C but this process is very interesting and anything =
I learn can be transfered to my students=2E =
Thanks=2C
Brian
Brian Scott Robinson=2C MHP =
Professor =
Savannah College of Art and Design =
School of Building Arts =
Historic Preservation Department =
P=2EO=2E Box 3146 =
Savannah=2C GA 31402 =
912 525 6940 office (Mon/Wed only) =
912 262 1202 home (students emergency only) =
brobinso=40scad=2Eedu
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=3CDIV=3E
=3CTABLE class=3Dblue=5Fborder style=3D=22BORDER-COLLAPSE=3A collapse=22=
cellSpacing=3D0 cellPadding=3D4 width=3D=2280=25=22=3E
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=3CTR=3E
=3CTD=3EOyster burn issues=3C/TD=3E=3C/TR=3E
=3CTR=3E
=3CTD=3E
=3CP=3EJust got back from watching a rick with oyster shell lime=26nbsp=3B=
burn at =3C/P=3EAshantilly=26nbsp=3Bin Darien=2C Georgia=2E I have sever=
al issues with the process and also several questions=2E =
=3CP=3E=3C/P=3E
=3CP=3EFor those of you not familiar with this historic=26nbsp=3Bprocess=
=2C a series of pine logs are stacked and oyster shells are placed insid=
e=2E The entire mass is set on fire=26nbsp=3Bwith the=26nbsp=3Bgoal of c=
reating quicklime which will then be used for a variety of traditional l=
ime based construction products including stucco=2C whitewash=2C lime mo=
rtar=2C and plaster=2E Photos and video are available=26nbsp=3Bat http=3A=
//www=2Emyspace=2Ecom/professor=5Frobinson=26nbsp=3B=26nbsp=3B=2E =3C/P=3E=
=3CP=3EI tend to discount the current conventional wisdom that this=26nb=
sp=3Brick burn process was the main method of producing quick lime=26nbs=
p=3Bin the southern=26nbsp=3BUS from=26nbsp=3B1730 - 1800=2E I see the e=
ntire process as rather unscientific and extremely=26nbsp=3Blabor intens=
ive=2E The process I saw today was conducted by a retired=26nbsp=3B=3C/P=
=3ENPS=26nbsp=3Bemployee from Fort=26nbsp=3BFrederica=2C a 1736=26nbsp=3B=
tabby fort located on St=2E=26nbsp=3BSimons=26nbsp=3BIsland=2C GA=2E He =
was not very receptive to=26nbsp=3Bmy=26nbsp=3Bsuggestion that=26nbsp=3B=
other methods=26nbsp=3Bcould have been employed in the creation of quick=
lime in colonial Georgia=2E Despite my diplomatic inquiry=2C I quickly r=
ealized that there was little information=26nbsp=3Bto be gathered from t=
his resource=26nbsp=3Bso I settled down=26nbsp=3Bto experience the proce=
ss as it was being presented=2E =
=3CP=3E=3C/P=3E
=3CP=3EFirst=2C this was only a =22demonstration=22 of the process=2E Th=
ere was little pretense that the material generated from this process wo=
uld=26nbsp=3Bbe usable=2E I question doing a less than accurate interpre=
tive demonstration when=26nbsp=3Bonly a little=26nbsp=3Badditional effor=
t could result in something much more worthwhile and accurate=2E One of =
the first problems I noticed=26nbsp=3Bwas that the oyster shells he used=
were fresh=2E These oysters=26nbsp=3Bhad only been eaten a few days ago=
=2E It is my understanding=26nbsp=3Bthat=26nbsp=3Boyster shells=26nbsp=3B=
would typically be extracted from prehistoric shell =3C/P=3Emiddens=26nb=
sp=3Bin order to gather=26nbsp=3Bmaterial that had been completely=26nbs=
p=3Bleached=26nbsp=3Bof salts=2E New oyster shells would=26nbsp=3Bhave a=
high salt content=2E I assume that=26nbsp=3Bany residual salts would be=
=26nbsp=3Btransfered to the mortar=26nbsp=3Bleading to potential future =
problems with mortar performance=2E =26nbsp=3BIs this accurate=3F
=3CP=3E=3C/P=3E
=3CP=3ESecond=2C=26nbsp=3Bthe entire structure burned to the=26nbsp=3Bgr=
ound in only an hour=2E It burned with a tremendously intense heat for t=
he first 15-20 minutes=2E The heat was so=26nbsp=3Bextreme that standing=
=3C/P=3Ewithin=26nbsp=3B20 feet of the rick was=26nbsp=3Bimpossible=2E=26=
nbsp=3BAnyone with any experience with pine logs know that they burn hot=
and fast=2E Oyster shell=26nbsp=3Bfragments started spitting out of the=
=26nbsp=3Bfire after about 10 minutes=2E How can=26nbsp=3Ba steady tempe=
rature be achieved with such a process=3F There was no way to regulate t=
he oxygen flow to the conflagration=2E It was essentially an uncontrolla=
ble fire=2E Why were the shells spitting out of the fire=3F Was this the=
result of residual moisture in the logs and the shells escaping=3F Were=
the shells actually=26nbsp=3Bburning and rehydrating=26nbsp=3B(with thi=
s residual steam)=26nbsp=3B=26nbsp=3Bwithin the initial 10-15 minute spa=
n=3F =
=3CP=3E=3C/P=3E
=3CP=3EWithin 1=2E5 hours the entire pile had turned to=26nbsp=3Bash wit=
h the white oyster shells still visible=26nbsp=3Bin the glowing ash pile=
=2E Once everything cools=2C how do you =3C/P=3Eseparate=26nbsp=3Bthe sh=
ells (quicklime) from the ash=3F Can you just mix up the mess together i=
n a hole and make it work=3F Shouldn=27t the ash be separated=3F=26nbsp=3B=
Aren=27t the shells on top=26nbsp=3Bexposed to cooler temperatures than =
the shells inside the pile=3F=26nbsp=3BHow can you ensure a consistent q=
uality of material=3F Should the entire mass be stirred regularly to eve=
n out the heat=3F Is it possible that the heat would be far too intense =
to create an effective result=3F=26nbsp=3B
=3CP=3E=3C/P=3E
=3CP=3EI estimate that=26nbsp=3B15-20 gallons of oyster shells were used=
=26nbsp=3Bin this process=2E I would guess that=2C at best=2C only 5 gal=
lons of quicklime would result from this burn=2E=26nbsp=3BIt seems that =
cutting and stacking 2 dozen logs 5 feet long=26nbsp=3Binto a rick rough=
ly 1=2E5 meters square is a lot of work to only create 5 gallons of quic=
klime=2E To construct a house the size of =3C/P=3EAshantilly=26nbsp=3B(3=
stories=2C approx=26nbsp=3B4000 sq=26nbsp=3Bfeet=2E walls 18=22 thick) =
using this process=26nbsp=3Bwould require the gathering and burning of a=
n entire forest=26nbsp=3Bof trees=2E=26nbsp=3B
=3CP=3E=3C/P=3E
=3CP=3EGerard Lynch=2C our mason friend from the UK=2C has clearly=26nbs=
p=3Bdemonstrated that with only 300-400 bricks and a little mortar=2C a =
small=26nbsp=3Blime =3C/P=3Ekiln=26nbsp=3Bcan be constructed=26nbsp=3Ban=
d fired up in=26nbsp=3Babout 8=26nbsp=3Bhours=2E =26nbsp=3BThis kiln=26n=
bsp=3Bcan remain on site and be reused over and over to burn calcium car=
bonate=2E His kiln=26nbsp=3Bburns at a=26nbsp=3Bmanagable temperature an=
d the heat can be regulated by increasing or decreasing airflow and fuel=
into the kiln=2E At the end of the process the kiln can be deconstructe=
d and reassembled on the next construction site=2E His kiln uses traditi=
onal material and techniques=2E It appears to me that it would be much m=
ore sensible to have a master mason build a temporary kiln on=26nbsp=3Ba=
construction site=26nbsp=3Brather than fell and stack dozens of trees t=
o achieve=26nbsp=3Binconsistent results=2E The argument that the NPS guy=
gave was that there were no bricks=26nbsp=3Bavailable during this perio=
d=2E =26nbsp=3BThe tabby c=2E 1741 Horton House located only 25 miles to=
the south of Ashantilly had bricks in the foundation that were=26nbsp=3B=
robbed out in the post civil war era=2E Evidence of these=26nbsp=3Bbrick=
s are still visible at the site so that argument does not hold water=2E =
Plus we all know that small loads of bricks and lime putty or dry hydrat=
e would have been easily transportable by ship=2E=26nbsp=3B=26nbsp=3B=26=
nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nb=
sp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=
=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=26nbsp=3B=
=3CP=3E=3C/P=3E
=3CP=3EThe more I learn about traditional building practices the more I=26=
nbsp=3Bunderstand that=26nbsp=3Bpast practitioners=26nbsp=3Bfocused on p=
rocesses that were based on common sense practices that were as straighf=
orward and simple as possible=2E Labor was precious and life was hard en=
ough without doing stupid things to make=26nbsp=3Bconstruction=26nbsp=3B=
difficult=2E I plan to return to the rick burn site tomorrow to gather s=
ome of the burned shells and take them to school on Monday=2E We will at=
tempt to=26nbsp=3Bhydrate the material and see what we=26nbsp=3Bget=2E=26=
nbsp=3BThe students will enjoy watching the material boil if nothing els=
e=2E =26nbsp=3B=3C/P=3E
=3CP=3EAny comments or thoughts about this process would be appreciated=2E=
=26nbsp=3BI am not a lime expert=2C but this process is very interesting=
and=26nbsp=3Banything I learn can be transfered to=26nbsp=3Bmy students=
=2E =3C/P=3E
=3CP=3EThanks=2C=3C/P=3E
=3CP=3EBrian=3C/P=3E=3C/TD=3E=3C/TR=3E=3C/TBODY=3E=3C/TABLE=3E=3CBR=3E=3C=
BR=3EBrian Scott Robinson=2C MHP =3CBR=3EProfessor =3CBR=3ESavannah Coll=
ege of Art and Design =3CBR=3ESchool of Building Arts =3CBR=3EHistoric P=
reservation Department =3CBR=3EP=2EO=2E Box 3146 =3CBR=3ESavannah=2C GA =
31402 =3CBR=3E=3CBR=3E912 525 6940 office (Mon/Wed only) =3CBR=3E912 262=
1202 home (students emergency only) =3CBR=3Ebrobinso=40scad=2Eedu =3CBR=
=3E=3CBR=3E=3CBR=3E=3CBR=3E=3C/DIV=3E
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End of BULLAMANKA-PINHEADS Digest - 9 Nov 2006 to 12 Nov 2006 (#2006-230)
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