Entry #4 [1/9/2026]

[Ashenstride]

Today, I'm picking up where I left off last time. I spent a good bit of time learning about FreeCAD's parametric dimensioning system using internal spreadsheets and links. With that, I can mock up some general parts with rough dimensions that I can adjust later as needed by changing the dimensions in the local part spreadsheet file. In fact, I need to look at if there is a local BOM system in FreeCAD, otherwise, I may see if I can integrate a parts-list into my parametrics spreadsheet-making Macro.

We are having a meeting later today, so I want to have a few things prepared for that. I'll start by working on the pressure vessel CAD file, then address the remaining BOM items as they are sourced.

[Ashenstride]

Brainstormed with Lawrence more. Sourced a good pressure cooker pot that's affordable and would make for a good proof-of-concept, and even a first prototype (with some modifications. Its a Hawkins pressure cooker, posted in the prototype parts considerations list.

I am considering the use of steel shot instead of magnetite/bentonite mixture. I believe the steel shot is more likely to make an excellent medium for rapid heating via conduction, as well as a good medium for cracking and disturbing the sample as a biochar shell forms, exposing fresh matter to the intense heat. Possibly a combination of large and small shot, or a mixture of all three. During our proof of concept, we can test different mediums and compare energy efficiency, proficiency, and speed of cycle.

[Ashenstride]

Meeting notes and takeaway:

Need to think of a convenient way to quickly cool down the environment and prevent over-heating of components. Liquid-cooled? Peltier boards? cooling/shunting fans?

[Ashenstride]

Next-steps:

Lock down a BOM for the pyrolysis test.
Send order request to Rob by next meeting.