5-gallon tilted drum — build guide

        [ LID KIT — sub-lid in stock lip lid ]
              |  hangs open on tilt; string/latch optional
    ----------+----------  high end (open / lid)
   /                       \
  |   substrate ~~~~~        |  36° tilt — crawl uphill
   \                       /
        | harvest bottle     hangs UNDER high end (6-o'clock)
        V pointing down
         o o o drilled drains  clustered at low point → catch pan
    ========================  legs / cradle / cinder-block wedge

Tune harvest height after first cycle if larvae stop short of the port.

Tools

Drill, assortment of bits (~4–9 mm), deburr file, silicone gun (harvest fitting only), welder or lumber screws, inclinometer, marker, square. Lid kit: knife/jigsaw, strap hinges, optional string/latch (see 5-gallon-lid).

Build sequence

1. Inspect the vessel

• Food-grade plastic or clean steel pail only.
  
• Reject containers that held solvents, pesticides, or unknown chemicals.
  
• Wash and dry.

2. Build the stand

Target: high support at the lid/open end, low support at the closed bottom. Height difference between cradle centers ≈ axis × sin(36°) ≈ 216 mm for a standard US 5-gal. Leave clearance under the high/lid end for the hanging harvest bottle and for the lid to swing open downward. Confirm 36° ± 2° (band 35–38°) with an inclinometer (phone app is fine). Soften any hard edge that bears on plastic (hose scrap, rubber, folded cardboard)—point loads crack pails.

Option A — Cinder-block wedge (fastest hack)

Wedge the bucket between concrete blocks / CMUs (local “bloques”) so the shell sits at ~36°. No welding, no lumber cut list.

• Common 8×8×16 in (≈200×200×400 mm) blocks work: e.g. one course under the low/tail and two courses (or one course + a half/turned block) under the high/head, then nudge spacing until the inclinometer reads ~36°. Exact stack depends on block size—tune by angle, not by a fixed BOM.
• Seat the shell in the hollows or on padded flat faces so contact is wide. Optional scrap wood or rubber “saddle” on the block so the pail does not rock on a sharp edge.
• Keep a gap under the high end for the hanging bottle and hanging-open lid. Slide the leachate catch under the low end between blocks.
• On soft ground, put blocks on a scrap plank or packed gravel so they do not sink unevenly and kill the angle.
• Strap or string the pail to the blocks if kids, dogs, or wind can knock it—friction alone is a learning-unit compromise, not a permanent outdoor guarantee.

Best as a low-cost first standalone stand before paying a welder. Same drilled bucket becomes a rack module later; only the stand changes.

Option B — Lumber or welded frame

• See drawings/side-elevation.svg.
  
• High pair of legs at the head; low pair at the tail.

Welded frame (preferred cradle): 25–50 mm square tube legs with upper + lower formed flat-bar rings and push-on EPDM edge trim on the contact edges (same recipe as the modular open cradle). Add a head stop so the pail cannot slide downhill. Skip expanded-mesh baskets and peel-prone adhesive neoprene for outdoor damp use.

Lumber frame: 2×4, lag screws, same geometry; pad contact with hose scrap or EPDM if available. Prefer this (or blocks that are tied down) when the unit lives in a busy yard long-term.

3. Drainage and aeration (process modules only)

Collection / kitchen pails: skip this step—leave the shell intact.

Process / rack modules: follow 5-gallon-rack § drains, aeration, and adult entry. Summary: dense 4–8 mm low-corner drains; side/upper aeration (off bottom curve when tilted); ~7–9 mm adult ports in the open-end third; no interior mesh; optional barb for PVC. Slide leachate catch under the cluster. See /articles/leachate/.

4. Head access (lid kit)

Build BSF-5G-LID: cut a sub-lid into the stock lip lid, hinge so it hangs open on a 36° rack, optional string or latch. Same lid on collection and process shells. Do not cut a hatch into the curved barrel wall.

5. Harvest bottle port (process modules only)

Collection pails: skip.

Process / rack modules: follow 5-gallon-rack § harvest—near-rim underside hole ~20 mm past the metal band, threaded bottle connector, bottle hangs down under the high end. Leave cradle clearance for bottle + open sub-lid.

6. Mount and leak test

• Seat bucket in cradle or block nest; strap or string snug, not crushing.
  
• Pour 4 L water; check drains and harvest fitting for weeping.
  
• Fix before adding feed. Confirm the lid swings open and hangs clear of the stand/blocks.
  
• Re-check tilt after the first wet load (blocks can settle).

7. Startup

• Shade under roof or tarp (/articles/tank-design/ — shelter section).
  
• Start with 1–2 kg wet feed and torn plain cardboard; a few active larvae are optional (attractant smells only)—see /guides/setup/#seed-a-new-bucket.
  
• First self-harvest often 2–4 weeks (extension guides).
  
• If migration is weak, verify moisture (~70–80% wet basis) and tilt (stay in 35–38°).

Plastic vs metal