This is my first post here. Before I start I want to thank you Matt for the way you have shared your work and growing skill with RMH's. You have been respectful, encouraging and inclusive.
I'm moving toward building castings similar to the ones you have done Matt and am still looking for ideas and info on the recipes people are using. It seems that your recipe-- 14 perlite, 14 fireclay, some furnace cement-- is the most quoted and probably used at this point. I would like to see more talk about recipes and what their ingredients do, how they interact with each other, and how to get them. For example, i'm in the midwest and still don't know what fireclay is or how to get it.
The other area I'm looking at is material availability and reviews: furnace cement, fiberglass rolls, fiberglass reinforcers in mixes, ceramic glass, door frames for side loaders, etc. If there was a way to categorize some of these areas such as "recipes", "materials" which included ongoing reviews (stories of success and failure), cost, availability, that would help me greatly and i think others would appreciate it as well.
One last comment about shipable cores.I know there has been lots of talk about the need for/interest in a shipable cast core but honestly I think most people who frequent these websites want to do it themselves-- I know I do. That's where the open source free flow of ideas comes in and accelerates the learning process for all of us as we share our experiences instead of hide them and try to sell them. I'm not against selling cores but I think this technology is so recent and the dangers are so extreme I think we are still in the experimental phase. I envision that more skilled RMH builders and workshop leaders will emerge as time goes on just as there are skilled masons in every town. I'm not as sure about shipable cores.