Marvin Bartel on mon 15 apr 96
SORRY, I lelft out an item in the castable batch. Here is the corrected batch.
>from:
jims@connect.ab.ca Edmonton/Alberta/Canada
>Hi Folks,
> For the last several years I've been threatening to cast an arch (to
>replace the existing brick one) and possibly some blocks for the door -
>instead of re-doing everything in 2600's.
In the 1970's we used a homemade castable developed by potter by
the name of Leach in Albion, Michigan. Heis no longer living. Here is the
batch used. Do not wiegh the ingredients. Use a scoop or can to measure
by volume.
Sawdust (granular, not fine) --------- 1.5
Vermiculite (as used in potting soil) 1.0
Course grog (A.P Green P grog ----- 2.0 THIS ITEM IS THE CORRECTION
Fire Clay (A.P. Green) ------------------ 2.0
Portland Cement ------------------------- 1.0
Alumina ----------------------------------- 0.5
Water -------------------------------------- 1.5
This material is mixed dry first. Add only enough water to make it clump
when packed. We packed it in the forms using the end of a 2x4 tamper.
Mixing it quite dry reduces shrinkage.
We made a 2 chamber catenary soda vapor kiln with cast walls 4
inches thick. Expansion joints are left by placing paper in the castable
after forming a compound notch in the tamped material. The joints are
about every 18 inches or so. Door chuncks are done the same way. We fired
to cone 8 to 10 with gas.
CAUTION: Ours gave way after about 30 firings because we added 1
inch of mineral block insulation on the outside for fuel saving. This
caused the area between the two arches to begin to melt.
The portland cement makes it quite weather resistant, but it also
lowers the temp. Calcium Aluminate cement is made by LA FARGE CORP
someplace in NW Ohio. I can't vouch for the strength, but it has a higher
melting temperature. Kyanite is fairly inexpensive material high in
alumina. Adding some kyanite might help. It comes from Virginia Kyanite.
Hope this helps.
* * * * * * Marvin Bartel * * * * * *
Art Dept., Goshen College
Goshen IN 46526
marvinpb@goshen.edu
phone 219-535-7592
fax 219-535-7660
http://www.goshen.edu
* * * * * * * * * * * * * * * * * * *
See Goshen College Alumnus
Dick Lehman on Ceramics Monthly Cover
* * * * * * * * * April, 1996 * * * * * * * * * *
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