Customer Reviews for Harvey 32 oz. High Temperature Furnace Cement

This product is horrible. It completely disintegrated after the first use of my fireplace. I followed instructions precisely, but it did not matter. It just fall apart. See the pictures. Now I have to remove this somehow and find a really good product to install.

If you own appliances or fixtures that use open flames such as gas appliances, fuel fired heaters with fire boxes or other gas, coal, oil or wood fired appliances, you should have a pale of this on hand. It it a high temperature cement that can fix cracks, bind fire brick, etc. It's a thick paste that you apply to such a surface and the low heat actually cures the cement. However, in my case, I found yet another use for this product. My gas BBQ pit has a H-burner which consists of a pair of intake pipes, and two pieces of stamped metal that is attached together with a folded seam. The bottom piece has many tiny holes for the gas to escape. The problem is that every manufacturer makes their own specific size and shape burner so buying a generic is usually very difficult. This means you pay the long price for a replacement. I noticed this year, my BBQ was heating unevenly and getting far too hot near the valves. Looking closely, I could see the heat had rusted through along the seam allowing lots of gas to escape there. The rest of the burner was in good shape, but rather than chucking it, I repaired it with the furnace cement. After firing up to cure, I once again saw the gas coming out evenly around the entire burner. I will hopefully get 2 more years out of it.

This cement worked out perfectly for the cracks that I had around my fireplace. As you can see in the photos, the crack here was from the entire length of the fireplace. I'm not sure, but either hot or cold air could have been entering the house from that crack. I simply applied the cement along the wall and chimney to seal the crack. Now, no cold or hot air will enter through that crack.

So I got this to see if I could fix a cracked chiminea that we use as a pizza oven. I figured that it gets pretty hot & after reading about this I figured I had nothing to lose. I followed the directions & everything went fantastic. The sun was out & great weather was predicted through the rest of the week & weekend. I was so hopeful that I’d found the solution to our problem & get back to wood fired pizza again. NOPE. The next morning I woke up & it was pouring outside. I hadn’t covered it as there was no indication that it was going to rain. I quickly ran out with a large trash liner & taped it around the top part to protect where I’d spread the cement. Needless to say, it rained for 3 days & then today I finally took the plastic off to find all the cement cracked & crumbling down. So honestly I have no idea if it would’ve worked under other circumstances The product itself is easy to use (wear gloves, eye protection & read directions for safety precautions), but I’m really unsure if this would have fixed our issue for good.

Problem: The Pizza Oven is built with fire brick in a dome configuration. Under extreme temperatures the dome expands to form initial cracks following the brick lines. Solution: Hercules Furnace Cement was applied to theses expansion cracks, following the directions for application. A low temperature fire first, then a full blaze normally 1200 degrees. Hercules held up to the temperatures without the joints reopening. This is more than expected because the expansion occurred without cracking again. These bricks have been under high temperatures for about 6 years and the cracks appeared on day one. This product does everything that it claims. 5 stars...

I have used this Hercules Furnace cement to fix my wood pellet stove inside the house and outside. I needed to use this as my pellet stove heats up and regular cement just kept cracking up. on the outside, all the way to the end of the chimney I have used it as well so I can seal around and not worried about the heat cracking the cement and the water coming into my chimney.

The furnace cement spreads very easily. It cover's equally great. It doesn't crack or shrink. I used it around the surrounding area around the hot water exhaust as it connects to the concrete foundation and into the chimney. Buy this product because it works.

This is a fine product for boiler flue collection dome seating. It's not as viscous as Boiler Putty, but that's no longer available. For thick, vertical applications, it'll sag and run down. The (tedious) work-around is to apply thin layers and thicken the layer with a heat gun. Then the next layer can be applied. The Harvey's Furnace Cement adheres very well to clean, damp surfaces & cures quickly with moderate heat.The product has no detectable odor and washes off tools with water. It's too thin to use as brick mortar as the weight of the brick will squish it out. Apply in about 1/4" layers and heat gun it to give it strength. If it were thicker in consistency, this would be an ideal all-around product. PS: Don't ask Oatey (the manufacturer of Harvey's) a question. They won't answer but will spam your e-mail to death!

Would not harden after a week.

Product was what I expected. It turned into cement after application and allowed to dry. Plugged the hole in the furnace nicely.

The cement worked good

Great for repairing the cracked bricks in my woodstove, very easy to apply, large tub for a very good price.

It says this 6” vent cap was delivered today. I did not receive it. What gives?

Great product!! Seals rock hard and very easy to apply! Well worth every penny

Needed this to seat and seal replacement ash door in fireplace and separately to reseal a furnace flue going into chimney. Put on gloves and placed cement into openings and smoothed after installation. Worked well for me.

Works great on kiln bricks

Application went well. Haven't applied heat yet.

Simple to achieve good coverage and seal.

The product is easy to work with. It is smooth, like peanut butter, not gritty like mortar. it is best to apply small quantities in layers otherwise the drying time can be a few days.

I used to patch around hot water heater vent where it goes into chimney. Worked great

Didn't do anything. Did not stand the high temperature it said it would just fell apart.

Used Harvey Furnace Cement to seal exhaust vent after cleaning out chimney debris. Slightly gooey to start but remained firm as I applied the cement around the vent. Took 2 days to fully harden and am pleased with the outcome.