MEECO'S RED DEVIL #121 Furnace Gasket Cement and Stove Sealer - High Temperature Adhesive for Fiberglass Gasketing - Ideal for Repairing Small Cracks in Stoves - 10.3 Ounce Tube Cartridge (Gray)

My 1979 Grey Vermont Castings Resolute woodstove was overfiring (i.e. burning up a loaded stove too quickly and at far too high a heat). Was waking up to a cold stove. Typically overfiring is caused by unwanted ingress of air into the burn chamber. First I tried replacing all the door and window gaskets. Then I inspected the seams. The metal plates of the stove expand and contract and ultimately the caulking between the plates is destroyed. I cleaned out the stove completely and inspected the seams inside and out. Sure enough crumbling cement caulk and light could be seen by shining a very bright light from the inside of the stove directly at certain seams.After struggling to find a grey furnace cement locally I ordered Red Devil 121 on Amazon. The black stuff would have been butt ugly!I followed instructions and cleaned, then wetted surfaces to promote adhesion. I made sure to have a stockpile of rubber gloves, newsprint for wiping, a good caulk gun, and plastic silverware knife (this flexed and produced a pretty bead). I made sure to cut the tube on the smallest cut line on the nozzle. Consistency was perfect and the product flowed smoothly. I knew from the flow rate a lot of caulk was going deep in the seams. I left the stove in place, and some of the seams were awkward to get at with the caulk gun. In these places I used latex gloves and pressed caulk into place, then finished bead with knife. Clean up is easy with soap and water.After two weeks of running the stove that has included several instances of my wife or I forgetting to close the damper and thus manually overfiring the stove to 900 degr. F plus (that's as high as our thermometer goes!) the Red Devil has worked perfectly. The grey matched the Vermont Castings Grey perfectly and aesthetics were only improved. This morning it was 20 degrees and I came downstairs to be greeted by the woodstove I packed at 9.30pm the night before still cruising along happily at 400 degr F. No sign of cracking or wear yet.I don't know how long the Red Devil will hold up, particularly if we continue to mistreat our stove. We have a kettle that is supposed to whistle and tell us to close the damper but sometimes it doesn't whistle and we overfire the stove. The good news is we have easily more than half a tube left, and I made a cap for the tube with seran wrap in case I need a second application. And it's not an expensive product to begin with though. If I find durability to be an issue and I remember I will update this post. However given our stove abuse I'm guessing it will continue to hold up well, and if it doesn't it may be our fault anyway.I'm really happy with my choice and with what I know now would definitely use this again.

If you have a fireplace which needs repair buy this. Most fireplaces have either firebricks or concretet slab inserts with brick patterns on them. We have the latter. They develop cracks over time which can be very dangerous if they become wide. Heat can penetrate the rear wall and are is a fire hazard.This material is perfect to fill both hairline cracks and wide cracks. It sets hard. Then you set a small fire which cures the mortar. Then it’s done and the fireplace can be used as normal.Saves a fortune as it’s a simple diy job so no need to call a brick layer. I understand that if you have separate firebricks not concrete slabs it is also perfect. Real peace of mind to know the fireplace has no cracks.

Used without a caulk gun, so very difficult to get it to come out although was able to make it work. That aside, worked like a charm once I was able to get it where it needed to be. Somewhat difficult to manipulate into the right places but worked very well with the bricks in my fireplace. Made several loose bricks completely solid and was pleased with outcome.

I had some moarter come off in the front of my fire box, so I got this to replace it. My fireplace has metal sides and back with fans to pump out the heat, and I noticed some gaps between the metal and stonework that I went ahead and filled while I was at it. This stuff bonded perfectly with stone, brick, and metal, and after burning two cords of wood, it still looks like I just did it. It was very easy to use, just lightly spray with a little water, and fill it in. It's even easy to finish any rough areas with a dampened finger without making a mess. I was able to fill a half inch vertical gap with no problems. Very happy with the end result.

The mortar went on smooth like butter! We repaired the crack in my chimney with one coat, and it dried fast. We were worried due to the heat and humidity this time of year, but it did not seem to be an issue. This is a really great product, and a must to have on hand if you have a chimney.

I used this product to adhere wood stove brick to the inside of the wood stove. It only worked one month and the bricks came loose again. It is possible that both the brick and side of the stove are still contaminated - not allowing the cement to work properly. However, I am still trying to find a cement that works good inside of the stove....Update 25Oct15: I re-cemented the three loose bricks inside my stove again with this cement. Going to let is dry for a week before firing the stove. I also will ensure I don't just throw my wood in while using the stove. Maybe I will get better performance this time.

I recently rebuilt my kiln that had a broken/missing piece of brick and another section where the brick was cracked all the across the back of the kiln. The Red Devil mortar saved me from having to buy expensive bricks to replace the rear bricks that had cracked. I was able to mortar them together with no problem. The other area was the top right rear of the kiln where a piece was broken off and missing. Instead of having to figure out how to cut the entire brick I just cut out a section of a new brick and mortared it onto the existing brick. I have used the kiln quite a few times since and it has held up really well, maybe even better than the original bricks.