Durability check of the Ceramic fiber board in my core

Hi all;  
Watching my dragon burn over the last few weeks, I noticed as each stick of wood burned down it would fall over into the burn tunnel. New wood on top was pressing down on the old.
I started wondering about the condition of the ceramic board where it meets the split bricks of the feed tube. Seemed like there could be damage occurring at the beginning of the burn tunnel floor.
If so a spring repair would be in order... cutting out the bottom of the burn tunnel and placing one more split brick on the floor.


This morning despite the single digit temps outside. Before firing her off , I removed the peter channel and cleaned the ash from the burn tunnel...

Matt Walker had told me that the C.F. board got more durable after firing.


I am very happy to report, He was (as usual) 100% correct !  The C.F. board was as smooth as the day I installed it. Zero damage from any wood pressing down on it.

Over a very long time it could become a problem spot.  In a future build I may use 1 more split brick on the floor inside the burn tunnel just to be sure it out lives me and our grand children.

Thanks for the update Thomas. I'll be all good to go (Thanks to you) once I get around to switching over my dragon to ceramic fiber as well.

Curious if you have peeked into the bell and seen if ash has accumulated on the bricks that jut out and now are insulating (on the top side and part of the wall they jut out of) rather than extracting heat.
Perhaps not enough to worry about?

Hey Gerry;
  Although some of those bricks were solid , the largest part  had the holes in them.  Ash falls rite on thru. The little bit that is covered is not enough to worry about. Besides from the bottom up they still catch and hold heat.  
Now that I am thinking about it...(oh no) those ash covered bricks would heat up sooner...and release it slower...  

I read somewhere a comment by Peter.  Single skin bells built with many internal protuberance's, had less cracking problems than those with none.
Now I think I may have figured out why. (Light bulb flickering  temporarily)
By heating sooner than the outer skin and holding that heat longer with their insulating top, they are giving a much smoother temperature gradient and therefore the skin is not experiencing as much thermal shock ?


Ha Ha if true, I imagine it was further along in Peters comments.... I just didn't read that far.

Thanks for the timely info Thomas.  I was going to extend firebrick through the burn tunnel up to the riser anyway, but very useful info to know anyway.  As usual, you are ahead of where many of us are on our build and testing timelines.