Using a Skutt EnviroVent with an L&L Kiln: Practical Guidance and Real‑World Fixes

When potters upgrade to a new L&L kiln, they sometimes try to reuse an existing Skutt EnviroVent or EnviroVent 2 downdraft system. Although the two brands can be made to work together, their designs and venting philosophies differ enough that extra care—and occasional modification—is required. Below is a condensed narrative of one potter’s experience, the challenges she met, and the steps that ultimately produced a safe, stable, well‑vented kiln.

1. Understanding the Design Differences

• Air‑intake strategy.
  Skutt’s instructions call for drilling holes in both the kiln floor and the lid, allowing fresh room air to mix with exhaust as it is pulled downward. L&L kilns, by contrast, rely on the small gaps around element holders and the two ¼‑inch holes drilled in the bottom slab; no lid holes are necessary. This distributes incoming air more evenly, avoiding weakening of the lid. (hotkilns.com)
• Mounting geometry.
  Skutt’s vent cup is held against the kiln bottom by a spring‑loaded metal post that bears upward on the floor. L&L stands are taller and shaped differently, so that spring tension can force the kiln to “float” slightly above the stand rather than sit flat.

2. First Firing: A Surprising Rocking Motion

After a successful cone‑5 firing, the potter pressed STOP and the kiln rocked front to back, as if the bottom slab had bulged into a shallow dome. Once fully cooled it rested flat again, but the movement raised serious safety concerns when loading a heavy, glazed ware load. (hotkilns.com)

3. Isolating the Cause

L&L technical support had never seen that behavior and suspected the vent hardware. They recommended firing once without the vent attached. Without the cup and post, the kiln stayed perfectly stable through a repeat glaze firing, confirming the vent installation was the culprit. (hotkilns.com)

4. A Practical Fix

Wanting to keep the EnviroVent, the potter devised a simple modification:

1. Removed the spring‑loaded post so no upward force pressed on the kiln bottom.
2. Cut a compliant fiber‑blanket gasket to cushion the vent cup against the underside of the bottom slab.
3. Braced the cup from below with kiln brick and a broken shelf that rested on the stand, not on the kiln floor itself.

With those changes in place, a cone‑5 firing (with a hold) completed smoothly—no rocking, no fume backflow, and acceptable draw through the vent holes. (hotkilns.com)

5. Recommendations Going Forward

• Drill only the two ¼‑in. floor holes that L&L specifies; omit lid holes altogether.
• Eliminate upward spring pressure. If you keep the EnviroVent, support its cup from the stand or floor so the kiln bears directly on its stand.
• Test without the vent after any installation changes to be sure the kiln sits solidly.
• Consider the purpose‑built L&L Vent‑Sure system for a plug‑and‑play solution that matches the stand height and floor construction.
• Inspect wiring regularly. Any downdraft vent that pulls corrosive fumes past the control box risks long‑term damage if leaks develop.

6. Key Takeaway

A Skutt EnviroVent can serve an L&L kiln, but only if you compensate for the structural and airflow differences between the two brands. By removing upward force and letting fresh air enter solely through the designated floor holes and element gaps, you can achieve reliable downdraft ventilation without compromising kiln stability or safety.