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Imco 800 Fireclay

Alternate Names: IMCO 800

Description: Smooth plastic red fireclay

Oxide Analysis Formula
CaO 0.18% 0.01
K2O 1.69% 0.06
Na2O 0.15% 0.01
Al2O3 28.60% 1.00
SiO2 53.20% 3.16
Fe2O3 4.51% 0.10
MgO 0.67% 0.06
TiO2 1.27% 0.06
LOI 7.30%n/a
Oxide Weight 321.94
Formula Weight 347.29


The manufacturer claims this is a milled and air floated Lincoln fire clay. It is an excellent all purpose clay with high strength and plasticity.

Ground to 200 mesh, this is a refractory plastic smooth tan burning very smooth plastic clay with kaolin-like working properties. Although referred to as a fireclay, it bloats by cone 11. It is yellowish in the raw state.

To formulate a substitute for Newman fireclay we mixed this 50:50 with Carbondale Red and added 15% silica and made a body having a recipe containing 50% Newman. The results showed that this mix has less color than Newman and is quite a bit more vitreous. Much more silica will be needed to cut the maturity and this will result in loss of color making the addition of iron necessary.

Physical data can be found on the link to the product information web page of the manufacturer.

Related Information

IMCO 800 Fireclay fired bars

Tap picture for full size and resolution

Cone 10R (bottom) and cone 10, 8, 7 and 6 oxidation.


Materials Imco 400 Fireclay
Materials Fireclay
Materials Lincoln 8 Clay
Materials C-Red Clay
Materials Newman Red Clay
IMCO information on their mined clays
Typecodes Fireclay
Fireclays are non-kaolin non-ball clay materials similar to stoneware clays but lacking fluxing oxides. Many fireclays have a PCE of 28 or more.
Typecodes Refractory
Materials that melt at high temperatures. These are normally used for kiln bricks, furniture, etc. or for ceramics that must withstand high temperatures during service.
By Tony Hansen
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