Promethium Line · Buffer Tank with Removable Roof & Pressure Gauge · 28–32 mm Grimdark Wargaming Terrain

### The pressure tank of the desert refinery

B-02 is an armoured, riveted buffer tank that brings a big sight-blocking mass into the refinery. It has a walkable roof that lifts off, a maintenance platform, a red pressure tower and a pressure gauge with a turning needle that tracks the terrain action STEAM. It plugs straight onto pipe bridge A.

### Features

- Footprint 6″ × 4″ (152.4 × 101.6 mm), the base plate is the terrain area
- Roof and maintenance platform at 76.2 mm = 3″: free platform area 68 × 46.4 mm, tank roof 68 × 68 mm. A 40 mm base fits on both without overhang.
- Infantry passage under the platform: 69.8 mm clear height, a 32 mm base passes
- Roof and its railings lift straight off for transport
- Pressure gauge with a turning needle (0 / I) and a separate steam token S
- Railings with 24 mm armoured parapets and vision slits on the roof and platform
- System flange Ø 44 mm at 89.2 mm, flush with the left plate edge: connects to A without an adapter
- Rules card pocket under the base plate

### Game use

Rules for Warhammer 40,000, 11th edition. Unofficial fan-made terrain. Not affiliated with or endorsed by Games Workshop. Warhammer 40,000 is a trademark of Games Workshop Ltd.

- Category: Dense (suggested, agree before the game). The closed tank and the pressure tower block sight above 2″.
- Levels: 3″ roof and platform. The roof comes off for transport only, and the inside of the tank is not a level.
- Objective piece: no.
- Terrain action STEAM: at the start of your Shooting phase, one unit with a model on the maintenance platform can give up its shooting and charge for the turn to turn the gauge to I and put steam token S by the tank. Until the end of the next turn, models in this B have a 3″ shorter detection range (15″ becomes 12″, 9″ together with gone to ground). This works for the models of both players. It gives no Benefit of Cover and does not change BS. Then the gauge goes back to 0.
- Set-wide frame: terrain actions are optional. Each player can start 1 terrain action per battle round, across all modules and copies. Effects do not stack.

### Print settings

- PETG, 0.4 mm nozzle, 0.2 mm layers (first layer 0.2 mm)
- 3 perimeters, 4 bottom / 5 top layers, 15 % gyroid, 240 °C nozzle / 80 °C bed, fan 30–50 %, bridge fan 100 %
- No supports, no brim. Every part fits a 220 × 220 mm bed and is already in print orientation.
- 20 printed parts on 4 plates (A–D), plus the flange coupon (plate T)

Print time and filament (PrusaSlicer 2.9.6 estimate, heat-up not included):

- T · Flange coupon, print first: 0 h 28 min · 4 g
- A · Base plate + card frame: 3 h 41 min · 42 g
- B · Tank, roof, name plate: 6 h 35 min · 81 g
- C · Maintenance platform + fittings: 2 h 39 min · 28 g
- D · Pressure tower, connector, steam token S: 3 h 34 min · 44 g
- Total A–D: 16 h 29 min · 195 g (with coupon: 16 h 57 min · 199 g)

### What else you need

- 2 magnets, 5 × 2 mm discs (plus 4 if you fit them in the coupon)
- Glue. No screws or filament dowels needed.

### Assembly highlights

- Print the coupon first and check the system pin and magnet fit on your own PETG.
- Magnet polarity, the same on every flange of the set: look at the flange face with the notch at the top. Left magnet north pole out, right magnet south pole out. Test against pipe bridge A before gluing.
- The tank sits on two square tenons, the platform slides into the tank mount with a bevelled tongue and rests on the support trestle.
- Glue the small cap only onto the axle tip of the gauge, not onto the needle, so the needle keeps turning.
- Set the roof in loose, do not glue it. Keep the flange faces free of paint.
- Step-by-step instructions with all parts are in BUILD_GUIDE_B.pdf.

### Works with the rest of the set

Promethium Line is a coherent terrain set in ten modules with one story. The mountain is the promethium source, drill station D taps it, and the pipeline H carries it past pipe bridge A and buffer tank B to the refinery with tower E and the bombed tower turned drill rig F. Loading yard G closes the chain. Craters K, the tanker wreck C and field defences J show the fight for it.

Every pipe flange in the set fits every other flange: Ø 44 mm, a square system pin and two 5 × 2 mm magnets. B shares the 89.2 mm high line with A, D, E and F, and the pipeline riser H12 connects it to the 28.0 mm ground line. Placed next to A, the platform sits at the same height with a 12.2 mm gap, so the two stay separate standing areas. See the Promethium Line collection for all modules.

### Files

- Model files: all single STLs in print orientation, plus one PrusaSlicer 3MF project per print plate, named job_<plate>_….3mf (T, A, B, C, D). There is no G-code. Slice the 3MF projects with your own printer profile.
- Other files:
- rules_card_B.pdf: the module's rules card, 85 × 54 mm, for the card pocket
- TABLE_RULES_card.pdf: one card for the whole table (Core Rules reminder, objectives, terrain actions), two sides
- BUILD_GUIDE_B.pdf: parts list, plates, magnet polarity and step-by-step assembly
- RULES.pdf: all set rules in full, with Core Rules references and the balance maths
- source_B.zip: the parametric source code, to change tolerances and rebuild every STL
- Print all cards at 100 % (no page scaling). The Table Rules card has two pages: cut them out and glue them back to back.

### How it was made

Designed with AI assistance as parametric Python CAD code (build123d / manifold3d) and checked by automated tests: watertight meshes, overhangs of at most 45°, bridge lengths, collision checks of the full assembly and a PrusaSlicer run for every plate. It has not been test-printed yet. The fits are designed, not proven on a real printer, so print the flange coupon first. Makes and feedback are very welcome.