I reattached my tuyere today, and need to fill in cracks. there is also two slots that look like they were for a different clinker breaker. The forge I have probably had a different tuyere than this one.
I have acess to fire clay, furnace cement and some stuff at home depot that is for patching fire brick that comes in a caulking tube.
Which is the proper one to use, or can any of them work? thanks. again

I think any of them would work but as to which would last the longest....
Id start with either the cheapest or try the patching mortar

Ive read all sorts of good things about ITC-200 EZ Ceramic Fill
(the whole line in fact) ITC 213 Ceramic Coating for Metals ect

Id likely go dig a hole in the backyard for some clay and see how long that lasted
then maybe repeat that next time with a topcoat of ITC100 :p

I"ll go get my shovel! thanks.