Last year I made some new nozzles from 4" X 1" steel flatbar and cut slots in them similar to the original refractory brick nozzles, after 1 year (10 cord ) of use they have deteriorated very badly, I have included some pics. Part of one of them has been eroded down to approx 1/4" and one of the nozzles originally 3/8" wide is now approx 1 1/2". and they are warped as well. I made a new one today from stainless. I used 2 pieces of 3" X 1/4" flat bar and bent it 90 degrees and welded 3/8" flatbar in between as spacers to form the nozzles, it is all one piece. Materials and labor (bending) was $90.00 and I did the welding. I will report back as to how they hold up. As you can see in one of the pictures my ledge on the main refractory is deteriorating a lot as well.