Six hopper conversions, six first drafts
Cut-cone hoppers built from Grade C containers are the fab bay's most-requested autumn job. None of the first six worked properly, and the reasons were all different.
- Sheet
- 45
- Revision
- 2026-10
- Scale
- 1:1
- Drawn at
- Peoria IL
A tote turned into a hopper is one of the most satisfying things we build and one of the easiest to get subtly wrong. Six early builds, six different failures, all of them obvious in hindsight.
The cone was too shallow
We cut a 45-degree cone because it used less of the bottle. Shelled corn bridged across it within two loads. Dry granular material needs steeper walls than intuition suggests — we now cut 60 degrees as standard and steeper for anything that packs.
The outlet was the original valve
Reusing the 2-inch butterfly seemed elegant. It is far too small and the seat jams on dust. Hoppers get a slide gate, cut fresh, at least 6 inches.
No cage reinforcement at the cut
Removing the bottom third of a cage removes the structure that holds the rest square. The frame racked under load. Every build since gets a welded ring at the cut line.
Discharge height ignored
Beautiful hopper, perfect flow, two inches too low for the customer's auger inlet. We now ask for the receiving height before we touch anything, and build legs to suit.
Flame-cut edges left raw
A ragged HDPE edge catches material and eventually cracks. Edges are flame-polished now, which takes four minutes and prevents a return visit.
No vent
Fill it fast and the displaced air has nowhere to go, so the fill slows to a crawl and dust blows back at the operator. A screened vent on the lid solved it permanently.
Every one of those builds went back to the customer corrected, at our cost, which is the only honest way to run a fabrication shop that is learning. The current drawing is the sixth draft and it has been stable for two seasons.
The current specification
- Base container
- Grade C used 275 gal, known dry history
- Cone angle
- 60° standard; 70° for ground feed and anything that packs
- Outlet
- 6 in or 8 in slide gate, cut fresh, bolted flange
- Structure
- Welded ring at the cut line, legs to the customer's discharge height
- Vent
- Screened lid vent, 4 in
- Edges
- Flame-polished, no raw cuts in the material path
- Capacity
- About 11 cubic feet usable after the cone
- Lead time
- 6 working days in season, 3 out of season
- Shelled corn, soybeans and pellets flow beautifully at 60 degrees.
- Ground feed, DDGS and anything with fines wants 70 degrees and a vibrator mount if it will sit for weeks.
- Salt and mineral mixes are hygroscopic — they need a sealed lid and they will still bridge if stored damp.
- Do not use these for anything you need to weigh accurately. A tote cage is not a load-cell frame.
Why Grade C is the right base
Every one of these builds starts from a container that failed grading for product service — stained beyond documentation, or with a bottle that would not pass a leak test for liquids but is perfectly sound for dry material. The cut removes a third of the bottle anyway, and the offcut goes straight to the granulator. Using a good container for this would be vandalism dressed up as sustainability.
Need one before harvest?
Send the discharge height and what you are putting in it. Those two facts determine the whole build, and we will come back with a fixed price.