Fireplace Firebox Repair

[TeeMan]

What is the main difference in these two products? Which is the best for use to repair cracks at the bottom of a fireplace firebox?

MEECO'S RED DEVIL Refractory Cement:
Product Description
A pre-mixed, fiber-reinforced, high temperature silicate mortar for setting, coating or repairing firebrick. Used extensively as the mortar between firebricks when building fireplace fireboxes. Will withstand temperatures up to 3000-Degree F. Requires heat to cure. Buff color.


MEECO'S RED DEVIL Furnace Cement and Fireplace Mortar:
Product Description
Premixed, ready-to-use high temperature silicates. Multi-purpose cements for bonding and sealing both masonry and metals with working temperatures up to 2000 deg. F. Designed for patching or repairing cracked or chipped firebrick and mortar. Effective in resetting and cementing furnaces, stoves, chimney colars, boilers, and duct work. Not intended for exterior use. Gray.

 

[Ted Jenkins]

My opinion is you are going the wrong direction. Both products will work as the manufacture intended. Why not replace all the lining at the same time. When I was repairing fireplaces and wood stoves during my off seasons making sure that the lining was perfectly intact was a requirement. There are many companies that stock high heat concrete cast panels. Order some sections that are larger than what you need and cut them to fit and sit back and enjoy your wood heater. Clay fire brick is easy to trim to fit also. Fire brick that is well fit into your unit will stay in place for years. For me trying to repair brick that has lived past its useful life is not the wise thing to do. For less than $50 you could buy brick, tools, and anything you need to make your fire box good to go. Thanks

 

[TeeMan]

Replacing the entire firebox bottom is an option, I agree; but which one of these would cover small cracks the best. For $5 it is worth a try...I assume the Furnace Cement and Fireplace Mortar would be the one best suited for that as the other seems to be for actual setting (constructing) with firebrick? I've got a high heat concrete cast panel as the bottom currently.

 

[TeeMan]

I went with the Furnace Cement and Fireplace Mortar to repair the small cracks since this seemed to be the best fit for the application. After burning some fires, I cleaned out the ashes and did not notice any cracking on the repair.

 

[Fireaxman]

Thanks for this post, very timely. I had my entire firebox replaced last year, but one brick has slipped out of the mortar somehow. Just noticed it yesterday and was wondering what to do about it. Will take your suggestion.

 

[TeeMan]

Thanks for this post, very timely. I had my entire firebox replaced last year, but one brick has slipped out of the mortar somehow. Just noticed it yesterday and was wondering what to do about it. Will take your suggestion.

If you had a brick come lose from the mortar your application may actually need the other product: MEECO'S RED DEVIL Refractory Cement, "Used extensively as the mortar between firebricks when building fireplace fireboxes." Note, they say this takes heat to cure. I assume you could set, let dry, then light a fire? I didn't have any firebricks, just the high temp stone, so that's why I chose the other product. Both of these products were under $5 at the local hardware store.