[RedstickJP]

Opening is 3 3/8" wide and 2.5" tall, 9.75" deep. You can see torch entry port on the front view pic. Have it going in angled toward the back. Thinking about changing it to come in from the back for the new blower and just plugging the old hole. And since I have the room, I'm thinking about taking a 2.5" pipe packing refractory around it to give me more of a circular interior. Can I use the fire clay mortar I have and just mix in other ingredients to make a cast able refractory? Or would I need to use something else? I've seen tons of diff recipes online, I just don't know what would work best on a budget