Clearing Frame Guide for Sandustry Wet Seed Lines

The Clearing Frame is a research unlock in Sandustry that actively pushes material along instead of waiting for gravity and conveyors to do all the work. Its signature job is pushing Wet Seed through water, which solves the single most annoying step in the farming chain: dry seed falls straight through the floating wet layer, excess wet seed drifts to the surface, and an unaided washing pool clogs itself. If your seed washer keeps stalling no matter how much you rearrange launchers, this is the unlock that fixes it.

What the Clearing Frame actually does

Frames push materials through water columns and across gaps, replacing manual digging or launcher tricks once the research is available.

Conveyor belts and filter walls only move material that lands on them in the right way. Anything resting somewhere with no conveyor underneath, such as material piled on top of a filter wall or seeds floating mid-pool, just sits there. Players describing the division of labor put it simply: material dropped on top of a static wall will not move, and clearing frames are the tool you have for exactly that problem.

In practice, the Clearing Frame behaves like a powered surface that shoves material in its facing direction, including material suspended in liquid. That is why it pairs so naturally with water. A wet-seed column built from clearing frames and normal conveyors underneath gives wet seed that gets pushed up by falling dry seed a route to fall back down into the wetting area and be carried onward into the launcher, so the cycle never dead-ends.

The wet seed problem it solves

Wet seed floats, and that single physics fact causes the whole logjam. Dry seed dropped into a pool sinks through the wet layer sitting on top, so fresh seed keeps arriving underneath while finished wet seed has nowhere to go. The wet layer thickens, drifts, and eventually blocks the inlet or overflows the basin.

The fixes that experienced players converge on are the same three moves. Launchers take care of excess wet seed that drifts to the surface so it exits the pool instead of building up. A filter at the top lets any dry seed fall back down for another pass, with a second filter below doing the same as insurance. And the clearing frames keep the pool itself agitated so wet seed is continuously pushed through the water toward the exit instead of rafting up. The water does not need to be deep; player-tested designs use no more than about 4 blocks of water depth, and often less.

Reference design: the half-full box of clearing frames

The most-liked community answer for wetting seeds is a box of clearing frames that is half full of water, with the water at least 2 to 3 blocks deep. Dry seeds are thrown down into the box from above. The frames push the seeds through the water so they wet evenly, and the wet seed leaves the box on the far side headed for your planters.

Build it with the exit in mind from the start. Wet seed should leave the box lower than it enters, so gravity helps the frames rather than fighting them. Keep the inlet covered so nothing else falls in, and give the surface launchers clear space to flick overflow wet seed out of the pool. A wall filter above the exit prevents wet seeds from climbing back up the column under heavier bursts, which is a common failure once you scale the input rate.

Clearing Frame or drip-fed water? The debate

Not everyone agrees the Clearing Frame is the first tool to reach for. One camp drip-feeds water onto seeds instead: a low outside water inlet prevents overflow, and wet seed simply drops out of the wetting spot directly into the planter row. For a small, low-volume line, that design has fewer moving parts and no research requirement.

The counterargument comes from players who load-tested both under real throughput. Their position is that the slow clearing frame setup handles higher throughput just fine, and that anyone who has run a drip-fed line under load knows exactly why the clearing frame exists and is necessary. Bursts of seed overwhelm a drip pool quickly, while a half-full frame box keeps pushing wet seed through water at a steady rate regardless of what arrives.

The practical split is volume. Drip-feeding suits a compact early line feeding a handful of planter boxes. Once seed arrives faster than a drip pool can wet it, or when you are reconfiguring a whole refining process, the Clearing Frame route is the one that survives the load test.

Compact builds with advanced filters

Once Advanced Filters are unlocked, the whole wet-seed stage can collapse into a tiny footprint. A working compact switch combines an advanced filter set to block water, a clearing frame, and a liquid vent, allowing only seed and wet seed through the assembly. Designs this small were popular right after Early Access launched, precisely because they replace an entire wetting room with a column a few blocks wide.

The frame's job in these builds is the same as in the big boxes, just miniaturized: keep the wet seed moving through the water layer and toward the exit so nothing accumulates. Because advanced filters handle liquids and gases as well as solids, the water stays contained while the seeds pass through. Stack the assembly under your seed output and it wets continuously with no launchers at all.

Beyond seed washing

Clearing frames earn their slot in other places too. Anywhere material comes to rest on a surface with no conveyor, such as the tops of filter walls or the shoulders of a belt line, a frame keeps it moving. Players tuck them under conveyor runs as insurance, so a missed particle gets shoved back into the flow instead of snowballing into a pile.

They also show up around heat and burning chambers, where mixed material tends to stall in awkward corners. Community lava setups pair advanced filters with clearing frames to keep material moving cleanly around lava chambers without clogging. If a lane in your factory only jams when you look away, a frame under the stall point is usually the cheapest fix.

Keeping throughput under control

A clearing frame moves material at its own pace, which players repeatedly describe as slow but steady. That pace is a feature: a washing stage fed at full belt speed still clogs at the handoff, because too much material arriving at once defeats any machine in this game. Throttle the seed feed rather than doubling the frames, and let the steady push rate set the rhythm of the line downstream.

Watch the handoff points when scaling. Wet seed leaving the frame box needs a clear drop into the planter box row, and gold filtered out of the seed stream needs its own lane so it cannot pile under the washing stage. If you are new to how wet seed becomes plants, the beginner guide covers the farming loop, and the wet seed location guide covers sourcing the water side.

Sources and version notes

This page reflects Sandustry Early Access v0.5.x as of August 2026 (v0.5.5, Update #2, released August 19, 2026). Behavior here is synthesized from Early Access Steam discussions, Reddit posts, and YouTube builds: the half-full box with 2 to 3 blocks of water, the 4-depth ceiling, the drip-feed debate, and the advanced-filter compact switch are all player reports, not independently verified. The official wiki's Research page would settle the exact unlock tier and gold cost, but it was unreachable at collection time, so those numbers are intentionally omitted. The general principle that material resting on static blocks stays put comes from player PSAs about filter wall mode.