Lynn Manufacturing 1/2” Thick 12" x 16" (2-Pack) 2300F Smoke Free Ceramic Fiber Board Fireproof Insulation, 3326A

Why I reached for this board

In the shop and around the house, I keep a short list of materials that solve heat problems without drama. A half-inch ceramic fiber board is one of them. I picked up the Lynn board in the 12 x 16 two-pack to tackle a wood stove baffle replacement and to mock up a small forge liner, and I’ve since pressed the offcuts into service as heat shields and test panels. It hits the sweet spot between workability and real refractory performance, with a couple of caveats worth knowing before you cut into it.

What stands out

Two attributes define this board in use. First, the binder is inorganic, so initial firing is genuinely smoke- and odor-free. That’s a relief if you’re installing indoors; I’ve had other boards give off a noticeable smell on the first burn as they drive out organics. This one doesn’t, and the stated 0.0% loss on ignition matches my experience—no wisps, no fumes, just heat.

Second, the rating is credible for serious jobs: 2300°F short-term and 2100°F continuous. That puts it in the proper refractory-insulation class for wood stoves, gas and pellet fireplaces, pizza ovens, small kilns, and forge applications. At a density of 20–24 lb/ft³, it’s a medium-density board—more rigid and impact-resistant than blanket, but still light enough to shape with hand tools.

Working with it: cutting, fastening, shaping

This material is approachable. Here’s how it behaved for me:

• Cutting: A fine-tooth hacksaw works cleanly if you take it slow. I also had good results with a carbide scoring knife followed by a careful snap on straight cuts, but at 1/2" thickness a full-through saw cut is more predictable. Power saws are overkill and make a lot of dust; avoid unless you have great dust control.
• Drilling: Standard twist bits work, but go light on pressure to prevent breakout on the exit side. Backing the board with scrap helps.
• Edges and fit: A sanding block or rasp trues edges quickly. The board abrades readily, so it’s easy to custom-fit tight baffle tracks or slip behind a stove collar.
• Fastening: It’s not a structural panel. If you must mechanically fasten, use large fender washers and don’t overtighten. I prefer setting it in place with refractory cement or a sodium silicate adhesive where appropriate.
• Curves: It’ll tolerate gentle arcs only. For real curvature, use blanket; for gentle bends, shallow kerfing from the back can work, but cracking is easy if you push it.

As with any ceramic fiber product, I treat dust like I would fine sawdust: respirator, gloves, eye protection, and a HEPA vacuum on cleanup. Wet-sanding minimizes airborne fibers.

Performance under heat

The real test is how it behaves during repeated thermal cycling and flame impingement. In my wood stove baffle replacement, the board handled high-fire runs without any smoke, slumping, or noticeable spalling. After several weeks of daily use, the surface has the expected discoloration—off-white to light gray—with a few hairline surface checks, but no structural changes or sagging.

In a small propane forge liner mockup, the board insulates well and resists point heat better than blanket alone. That said, sustained direct flame on bare board will erode the surface over time. If you’re exposing it to blast from a burner or dragging steel across it, plan on a hot-face treatment. A rigidizer or a thin refractory wash significantly improves abrasion resistance and slows erosion while tightening up the surface. For pizza ovens, I’ve used it as an under-hearth insulation layer beneath firebrick with excellent heat retention—just don’t use it as the wear surface; it’s an insulator, not a cooking deck.

Durability and limits

No ceramic fiber board is indestructible, and this one’s no exception. A few realities:

• It’s brittle in flex. Treat it like thick drywall: support it well, avoid prying, and don’t expect it to bridge gaps without backing.
• Edges chip if knocked around. Cut slightly oversize and then dress to fit rather than forcing tight installs.
• Abrasion and flame erosion require surface protection in high-wear zones.
• Thermal cycling introduces small surface checks over time, which is normal and does not materially affect insulation performance.

Within those limits, it holds up. The board does not shrink noticeably under normal service, and the absence of organic binders means it doesn’t “cook out” and crumble early in its life.

Size and fit considerations

At 12 x 16 inches per sheet (two sheets per pack), you get 384 square inches total—about 2.67 square feet. For stove baffles and firebox panels, that’s enough for many small to mid-size repairs, or to create replacement tiles. For larger projects—pizza oven domes or full forge shells—you’ll be joining panels. Butt joints work fine if you bed them in refractory cement and support them behind.

Thickness is 1/2 inch. Check your appliance’s specifications before substituting; some stoves call for thicker baffles or specific materials. You can laminate two pieces to reach a thicker section, but I only do that when the design allows mechanical support across the seam.

Safety and cleanup

Cutting and sanding produce fine dust. My routine:

• Wear a P100 or N95 respirator, gloves, and eye protection.
• Work outside or under good extraction.
• Score or wet-sand to reduce airborne fibers.
• Vacuum with a HEPA filter; don’t dry sweep.

Once installed and fired, the surface becomes less dusty, especially if you coat it.

Where it fits best

• Wood and pellet stoves: Replacement baffles, side liners, and heat shields where insulation is as important as flame resistance. The smoke-free first fire is a big plus indoors.
• Gas fireplaces: Heat shields and combustion chamber panels where you need clean installs with predictable behavior.
• Pizza ovens: Under-hearth insulation and door cores. Do not use as a cooking surface.
• Forges and kilns: Lining panels and burner blocks, ideally with a rigidizer/wash hot face for longevity.

Alternatives and comparisons

Compared to ceramic fiber blanket, this board is easier to shape precisely and stays where you put it without sagging. It also resists flame impingement better. Compared to dense firebrick or castable refractory, it insulates far better but is much less durable under abrasion and impact. If you need a hard, wear-resistant surface, use brick or castable over this board as an insulating layer. If you need complex curves, blanket is the simpler path.

What I’d change

I’d love to see larger sheet options to reduce seams on bigger builds, and a factory-applied rigidized face would extend life in high-velocity flame environments. Neither is a dealbreaker; both are wishlist items that would save time on certain projects.

Tips for best results

• Pre-fit dry, then bed joints in a thin smear of refractory cement.
• Seal the hot face with a rigidizer or refractory wash anywhere flame or abrasion is expected.
• Support the board fully; don’t rely on screws to carry weight.
• Label offcuts. Small pieces make great localized heat shields or spacer shims near hot hardware.

Recommendation

I recommend this Lynn board for anyone who needs a dependable, easy-to-work ceramic fiber panel for high-heat applications. It delivers on the fundamentals: credible 2100°F continuous service, a genuinely smoke-free first firing, and a medium-density feel that balances rigidity with workability. It isn’t a substitute for hard refractory where impact or heavy abrasion is likely, and it’s not meant to be flexed or used as a structural part. But as an insulating, shapeable lining or shield—and especially for indoor installs where odors are unacceptable—it’s an excellent choice. Use it within its strengths, give the hot face a protective coating where needed, and it will do exactly what you brought it in to do: keep the heat where it belongs without adding complications.