So glad to find this! Ok, Paul, here is my list of questions concerning the riser.
I noticed that Erica and Ernie's riser (video) was made of whole firebrick and not insulated. Are whole firebricks sufficient without being additionally insulated? Won't they eventually get too warm and deter the cooling effect on the outside of the riser inside the bell?
When collecting my supplies to build my RMH, I obtained a quarter inch thick 8" steel pipe to use as my riser, having read that the metal pipe used as a riser will burn out overtime because of the the stresses of extreme temperatures. My plan was to use perlite/clay as insulation around that riser as thick as possible within the bell. I found a 15 gallon barrel a 35 gallon barrel and a 55 gallon barrel. I thought maybe if I used one of the smaller barrels around the 8 inch steel riser and insulated the riser with perlite/clay, I would get a longer-lasting riser with that configuration. And of course, then next I had read that the thicker metal takes longer to warm up and charge the system. Overkill? I guess.
So then I had opportunity to come to the workshops! I feel bad for those who weren't able to make it. You missed out on a great learning experience. Yet, having had the experience of the workshops I now have a new set of questions.
) So much of those workshops was highly experimental that my questions are limited. But I have read about wrapping the riser in Rock wool. How do the insulating qualities compare between perlite/clay and rock wool? What about using the Dura board? I am also concerned about attaching the insulation with metal screen or wire where such high temperatures are involved. And have you yet cast a riser using Erica's ingredients? Or are the risers you're using made of the same material? It didn't seem to be the same to me.
I love the idea of the shippable core and I am definitely on board with that. I also would like to work on designing a more solid configuration that would piece together or that would be solidly cast to thwart those weak areas we saw. I think given the weight of the material will be sufficient for a thicker core.
Oh! One more question. This one concerns the second bell. Sending a pic of a design I'm considering. I am thinking that this will work just fine. I am concerned with the second bell because it is a 16 foot bench. Will the second bell capture that much heat so that it would radiate or am I just overkill?
Thanks again Paul!
I hope you like my pineapple story~