Crumbling mortar?

[eustis22]

For those who mortared their bricks in, do you have problems with your mortar? My refractory cement, from Rutland, is supposably good to 2000 degrees, yet after a few fires the mortar between my bricks disintegrates. Is it me? My cement? my bricks? I am using splits...should I be using fulls?

[NTBugtraq]

Most fire cement is not meant to be exposed to the fire, but where it is, it should be less than 1/4" thick. Did you use too much? Also, did you let it cure? It should cure for at least 24 hours, and I was told that the first fires should be slowly built up. Just passing along advice I received...I choose not to mortar my new arch as I know I am going to be moving it.

[eustis22]

the first time it happened I spread it thin. The second time I pt it on thicker. How can it not be exposed to the fire????

I can't recall if I let it cure or if I built a small fire after curing...I'll try that.

[NTBugtraq]

Well, its meant to hold the bricks to the sides (like a glue), and to fill in the very small gaps between stones to prevent embers from sitting on the arch surfaces...the fire brick is meant to be in contact with the embers. Its not so much that it cannot be in contact with fire, but that the contact should be minimal.

Cheers,
Russ

[eustis22]

It's not I disbelieve you, Russ. On the contrary, I think the mortar crumbles BECAUSE it's in direct contact with my flames. I'm just not sure how I can keep the fire away from the firebrick AND keep a roiling boil.

[NTBugtraq]

You shouldn't be trying to keep the fire away from the firebrick. You just want a minimal amount of mortar exposed. If its crumbling so bad you have significant gaps between bricks, try cutting some shims off a piece of brick and use them to fill in the holes. FWIW, I used no fire cement at all when I bricked my arch, so they will work fine without it as long as the bricks are reasonably snug.

Cheers,
Russ

[eustis22]

basically the bricks loosen up and fall onto the grates during the feeding....also my firewall collapses so the heat isn't all the way up against the back of the pan.

[NTBugtraq]

Well, now I'm really out of my depth, since as I said I didn't use fire cement on my arch.


Did your fire cement ever freeze? They say it becomes useless if it does
Rebricking would probably mean 1 if not 2 days without being able to boil, does it make sense to do that at this point in the season?
Have you talked to your supplier?


Wish I could be of more help...

Cheers,
Russ

[supersapper]

Did you use premixed or powder that you add water to? Refractory mortar should be mixed to a stiff but spreadable consistency. Allow it to dry for a day or two then build a small fire in the fire box to cure the mortar. I did mine this year and had no issues even after moving from the shop to its present location. Also when you spread the mortar on the brick, make sure you have full coverage, not just on the front edge.