Our buddy Tim Layton (https://timlayton.teachable.com/) was working on an 8x20 project and asked if we could build him a super-sized version of our SP-8x10 tray. It sounded simple: just cut the ends off of two SP-8x10 trays and glue them together. Here's the first prototype:
It worked great (https://timlaytonfineart.com/additional-uses-for-my-ultra-large-format-daylight-tray-by-stearman-press/)
Turns out he wasn't the only ULF photographer who wanted one! So we had to refine our process if we were going build more.
Thus we designed a couple of "splices". These are 3D printed parts that glue the two tray halves (and lid halves) together. It also allowed us to add slots/holes for the dividers and hold down tabs. It's hard to get a good photo of shiny black parts, so here's a rendering:
(Parts are shown in blue and gray for clarity, actual production parts are black.)
The SP-8x20 requires 600 ml of chemistry and can process:
1 sheet of 8x20
2 sheets of 8x10
4 sheets of 5x7
Here it is setup for 5x7:
More details are in the User's Guide: SP-8x20 User's Guide
Before you ask: Why no 4x5? Several reasons: first loading eight sheets was awkward; second, we'd have to design/build a center divider that ran the length of the tray and still allowed you to use the center hold down tabs; third, we don't think the demand is there (we'll wait and see, maybe it is.)
You can order one here: https://shop.stearmanpress.com/products/sp-8x20-daylight-processing-tray