North Star 18" Porta Roller Slab Roller Mason It has a more diversified

It has a more diversified selection of fluxes than other feldspars but also has one of the highest silica contents

Because of the back pressure generated by a large amount of clay being forced through a small orifice

Because it has such a low iron content

borax has been shown to improve the fit of glaze on greenware and bisque

M340S is alternate where the speckle is wanted

North Star 18" Porta Roller Slab Roller Mason It has a more diversifiedThe PortaRoller was designed for ceramic arts teachers who are moving from classroom to classroom and for studio potters who need a fully functional slab roller but have limited space. The PortaRoller has two rollers, much like the wringer of an old fashioned washing machine. Both rolls have a small diamond pattern ("knurling") machined directly into the metal to grip the canvas. The bottom roll is turned by the handle, but cannot move vertically. As