Lynn Manufacturing High Temperature Adhesive, 2000F Rated, Sodium Silicate, Water Glass, 40% Solution, 4oz bottle, 5602

I picked this up to fix a small crack in my wood stove and was honestly impressed. The Lynn Manufacturing High Temperature Adhesive goes on super smooth, dries hard, and can take serious heat. I’ve tried a few other “high-temp” products before, but this one actually lives up to the 2000°F rating — no flaking, no soft spots, just a clean, solid bond. It’s basically sodium silicate (“water glass”), but it’s clearly high-quality stuff. I used just a small amount and it went a long way. Once cured, it looked like clear glass and has held perfectly even after multiple burn cycles. You can tell this is made for real industrial or repair use — not a cheap DIY knockoff. If you’re repairing firebrick, sealing a metal stove, or just need something that won’t melt or fail under heat, this is the one to grab. Easy to use, reliable, and backed by a company that clearly knows what they’re doing.

We used it to glue a broken ceramic fire log. All we had to do was brush on some glue on each piece and let it dry and let it set until the nest day. And it's still glowing in the fire.

As the title says. It is what it is. I will note there was some precipitate that had settled to the bottom, which to be fair is typical of old silicate solutions.

This sodium silicate solution helped me restore a ceramic, flame guard (for a gas torch) that had broken into five, irregular pieces. I painted the solution onto the broken edges of the ceramic pieces, assembled them back into a cylindrical shape, and used a tiny rubber band to “clamp” the fragments together. In 30 minutes, the solution had set into a hard, clear, mineral “glass.” I could remove the rubber band “clamp” and the pieces of ceramic held together for handling without any additional support. I used more solution to fill some small gaps where chips of the original ceramic were missing. Per the instructions, I let the solution plus joined and patched pieces cure for 24 hours. Then, I used diamond files to remove the excess, hardened solution, and to shape the reconstructed areas. I was surprised at how hard the “cured” solution was, and how well it resisted abrasion from the diamond files. The reassembled and restored, flame guard was even stronger than before. I tapped on it with a small, brass hammer, to seat it into the torch nozzle, and it did not break apart. It has withstood the high heat from the blue flame of the gas jet without disintegrating. I am really impressed with this product. Its bonding strength and heat resistance on ceramic components is spectacular. P.S. I did not experience any fumes from this product, and it dilutes and cleans away well with water. Do be careful not to let it into your eyes or mouth, or to have prolonged skin contact, as the solution is a strong base (alkaline) that is caustic to soft tissues. UPDATE 05/08/2022: The cured sodium silicate easily sustains under heat from a blue flame, which is between 2000 - 3000 deg. F. However, unless sealed with a silicone or other, water-resistant coating or film, it will readily dissolve in water or upon contact with it. Also, the sodium silicate conducts electricity, and anything that is coated or permeated with it will not be insulated against electrical current.

I bought this after hearing Bob Andersen on youtube talk about repairing the gridcaps broken off old vacuum tubes. It does, indeed, work as advertised and one bottle will go a long way if this is all you need it for. Bonds to glass very well.