Reusable Steel Urn Form Plan

I’m building a concrete urn-style flower pot that finishes out at roughly 30" × 30". To pour it repeatedly I need a fully-detailed fabrication plan for a four-piece steel form held together with bolting flanges.

What I need from you
• Precise 2D shop drawings and a 3D model showing the urn profile, broken into four interlocking panels with flange locations, bolt patterns and clear assembly/disassembly steps.
• Material call-outs for a steel grade that will survive many pours and clean-downs—stainless or heavy-galvanized sheet/plate are obvious contenders, but I’m open to your expert suggestion as long as re-usability is front-of-mind.
• Cut lists, flat-patterns and bend radii so the segments can be produced by either welding, plasma, or laser cutting—whichever yields the most economical build without sacrificing accuracy.
• Moderate exterior detailing typical of classic urns (a gentle flare, lip and base ring) while keeping the inner mold surface smooth for easy release.
• Hardware schedule for bolts, spacers, alignment pins and any recommended release agents.
• Brief assembly guide and demolding sequence so one person can strip the form without damaging fresh concrete.

Acceptance criteria
• Finished internal cavity delivers a 30" ± 1/16" diameter and height.
• All four segments mate flush; no visible steps inside the mold.
• Bolting pattern allows full teardown in minutes with basic hand tools.
• CAD files provided in both native (e.g., SolidWorks/Inventor/Fusion 360) and neutral formats (STEP, DXF) plus PDF prints.

If you can combine sound engineering with practical shop experience, I’m ready to get started right away and will be close by to answer any clarifying questions.