M-340GS

M-340 with 0,25% added 60-80 mesh granular manganese and an additional 4% fine grog. Not quite as smooth as M-340 and sacrifices a little drying strength to get the added texture. Since there is only 4% grog, and only a portion of that is actually coarse enough to feel, there is no gain in drying properties (the most common reason for adding grog to clay bodies). Many customers buy it on the misimpression that it dries better, however M-340 by itself is an excellent drier (mainly because of its high dry strength). The presence of the grog is also an issue on functional ware because it introduces grit on rims and edges. It is also problematic in the forming process since it produces water splitting problems, most noticeable when pulling handles or throwing bellies and lips (the grog provides entrance points for the water). M-340S is more recommended.Contains manganese so, a kiln vent should be used during the firing. 

Characteristics:
Cone: 4-6
Wet Color: Grey
Fire Color
                Oxidation: Light Speckled Buff
Texture: Coarse
Average Shrinkage
                Oxidation: 
Average Water Absorption
                Oxidation:    
COE x 10-6: N/A

* Protect from freezing.