Meeco's Red Devil 610 Refractory Cement - Pre-Mixed Fiber-Reinforced High-Temp Silicate Mortar for FireBrick & Masonry Joints - Withstands Temperatures Up to 3000°F (0.5 Gallon) - Made in The USA

I bought this refractory cement to use for constructing a home made gas fired smelting oven. The cement is a dark gray color and has the consistency of warm peanut butter. It spreads nicely onto fire bricks and is easy to work with. When it dries, it has the same gray color, but slightly lighter. The cement air dries in 1/2 hour or so, good enough to handle something that was cemented together, but to really CURE the cement needs to be heated. For example, cementing one fire brick to another, after an hour of drying time, the two bricks can be (with considerable force) pulled apart. However, if the same setup is heated (I baked mine in the home oven at 500F. for a few hours) the same bricks will crack elsewhere before the joint fails. In summary, this cement works great, it's easy to use, easy to apply and cleans up with water. It dries "well enough" to handle assembled items, but for a full strength cure, the cement must be heated. (Added info 23 September 2014): One important thing to know: Do not "scrape off" excess, partially dried cement from a trowel back into the container. The scraped off pieces will cure even with the cover on the tub, resulting in hard chunks mixed with good cement. I suggest using a sheet of plywood or some other inexpensive, disposable item and scoop out the cement you need, then immediately cover the tub of cement. When you need more, scoop out more and re-close the tub. Never put any unused cement back into the tub, or it will ruin the whole batch. Another important thing: When this cement is not used for a while, the solids and liquids will partially separate, leaving tiny puddles of brown liquid on top of the gray cement. Do not dump this liquid out! Thoroughly re-mix up the cement and it will be fine. Yet another important thing: This cement is highly alkaline (caustic - like lye or drain opener) when wet (uncured). If you get some on your hands and it stays there for a few minutes, you will know it because it will start to sting. This will not cause any injury, it just hurts a bit. So if you do get any on your skin, immediately wash it off with a lot of cool running water (or better yet wear gloves when working with the cement). Note that the cement is NOT caustic and it is COMPLETELY safe once it is cured (dried). The fact that wet cement is caustic is not unique to this brand or item. Almost all "cement" type products (grout, concrete, etc...) are caustic when wet.

I needed to tuckpoint my fireplace, and rather than pay hundreds of dollars I decided to git it a DIY try. This stuff really works. The tricks are to chisel out all the old mortar and wire brush all the soot and ashes away so you have a solid base for it to stick on. Then put it on in _thin_ layers, like 1/8 inch and let each layer dry for 24 hours before the next one. When you make your first fire, build a small one. Low heat lets it cure slowly. Yes, it takes a few days but this process worked very well for me. The cement is easy to use--buy a smaller cheap trowel and a tuck pointing tool at a big-box store--and there's lots of it. I've been using my fireplace for two months now. I build big, hot fires from oak and hickory wood and have had no problems.

I wish I did a bit more research before buying this stuff to line my forge with. The stuff is still a good product, but for a mortar. I coated my kaowool with it, let it dry for quite a few days, then heated it super slowly, over the course hours. Once it started getting to forging temps, it bubbled up like crazy. Now.... it turns out the bubbles can be busted off and there is still a thin layer of this material on the other side of the bubble, over the wool.. so it's usable. Ive been using it that way for a while now, but it's starting to break down. You want "castable" refractory cement, for your forge, btw. I still use this stuff to cement firebricks back together that have broken and if i'm doing a hamon.

Arrived in a sealed plastic tub inside of a tied plastic bag. I assume for freshness. The product warnings are a little scary, but the product is a wet paste. No fine particles were flying around. It did require a little mixing, but that was expected and addressed on the packaging. It sealed up the small gaps between the fireplace brick panels very easily. Once it was mixed, it went on like a thick paste. It did not slide down the vertical gaps. It stayed in place quite easily. Once the panels were squeezed together, the gaps were less than 1/8” just like the instructions recommend. Even though the product says it doesn’t need to cure, I let it sit for a day to dry. The next day I lit a fire with a duraflame log and let it burn out. There was no bubbling or anything else like some have complained of. I suppose reading directions prior to use helps. 🤷🏻‍♂️

I'm using this, some old firebrick from a kiln, and a hacksaw to construct a pair of forges with arched ceilings. It's working great to repair broken bricks and hold the bricks together. Of, course I won't know how well it works till I've fired them up a few times: I'm sure it'll hold, but it's not porous, so I'm being careful not to seal up too much of the brick faces, so I don't trap air that could burst out. It is also very susceptible to water, even after it has set, but that may allow me to smooth out rough spots, since it easily forms little dingleberries that are hard to remove dry. My last thoughts are that this is not really an insulator, and it would be expensive to apply thickly.

Just what I needed to fix the inside of the fireplace

Product would puff up when heated and crumble away. Had bought two tubs and one was dried out more than the other. Messaged manufacturer but did not get a reply. Will not buy again.