What's the easiest way to repair the exterior of a clay chimney liner that is beginning to deteriorate?

The portion of my clay chimney liner theat protrudes above the main (brick) chimney is beginning to show signs of damage on the exterior, north side, where the clay looks to be friable in spots, such that clay chips could probably be easily broken away from the exterior surface.  Is there a good repair material available to fix this problem?

Burf8 years ago
If it is unglazed, there is a product called E-Z Patch for Saltillo floor tile. It comes in several colors, red, yellow, etc. and is available from most floor tile dealers.
Koosie8 years ago
I wanted to say plaster it (with cement) but rendering it would look better.
lemonie8 years ago
Rendering it?