Help me heal my brick....

This brick (photos below) is from a Serbian-made woodstove imported into the US.  When whole, the brick is about 14 inches long.  Because of the narrow dimensions of the brick, I'm not sure if there is a cement or glue that can fuse the two pieces together to be a strong as new??.......  A local woodstove supplier did not have brick of that length to cut down, so would need to custom order which might be pretty expensive.  I've reached out to the US importer to see of they have a stash of bricks for these stoves, but have not heard back from them yet.  Opinons as to whether this could be repaired?.....and if so, what kind of glue or cement to use for a good bond?  Thanks!

Many of the wood burners here in NZ have cast iron grates and back panels.

Without knowing the location of the brick in your firebox, would a cast iron piece fulfil the function of the brick if it can’t be repaired?

Gluing will rather not work. There is one compound for ceramists that fuses pieces together in kiln temperatures, but I never used it and you need a kiln.
Depending on the function of this brick and temperatures it sustains, you could drill it and tie it with high nickel alloy wire.
It can be easily cut from a large firebrick slab with a right equipment. I cut various bricks and stones to various shapes all the time and I have two 18x18x2.5 slabs at hand and Imer saw that can handle 1 m long cuts. If you really want I could fabricate one for you and you would email me a shipping label.

Is that brick or soapstone? Hard to tell from the photos.

Many of the RMH posse have shown advanced technique with casting refractory slabs and pieces.....would this be an appropriate path to replacement rather than repair?

It's important that the repair fills the gap and prevents damage to the stove metal.

The only "goop" I can think of is the stuff used to attach door gaskets on wood stoves. It comes in a caulking tube and goes a long way. Obviously it can take a lot of heat, though whether it can handle fire directly may be another matter.

Maybe you can stuff door seal fibreglass into the gap and seal it in with stove gasket goop?

My experience trying to patch or mend cracked firebricks and refractory bodies is a 100% failure rate. I don't think it matters how good the adhesive is -- in fact, a really good high-temperature cement might exacerbate the problem. The issue is that these materials experience thermal shock, over and over. Any difference in the expansion of the mass from one area to another puts a lot of stress on any weak spot and pretty much guarantees that a joint will move. So even a carefully repaired defect becomes a focal point that magnifies and concentrates the force across a tight gradient that also has the disadvantage of containing a different substance with its own, and possibly very different, coefficient of expansion.

I think the best chance of success is to use something that flows and has some give to it, like sodium silicate. I have brushed a dilute waterglass solution over hairline cracks in firebrick and they seem to remain stable. It's the same principle as lime mortar in masonry: use a material that can conform to a bit of movement and the structure as a whole is more resilient than one built with hard, but brittle, cement.

In this case, I don't think there's much hope of fixing that break. I would go with the recommendations of Douglas and Cristobal and replace with something monolithic, either cast or cut from a slab.

Thank you for all of these responses.....very helpful in guiding my decision here.  I have reached out to the US vendor of these stoves and they *may* have exact replacement bricks for this stove, so I will hear back from the person responsible for those issues sometime this week.  Thank you for your offer, Cristobal, to cut a new brick or two from your stock piece.....I will let you know what I find out about direct replacement and may still contact you about that if that vendor is not able to provide one.  I'm not sure if the stone is brick or soapstone, ..... only can say it seems rather soft compared to the firebrick I've had in other US-made stoves.  One more option I'm considering is to move this broken brick down in the brick-column within the stove:  The broken one was the top-most brick in the column.  If I were to remove the next brick in line and then replace it with the broken one, by having now a whole brick on TOP of the broken brick may give it more integrity..??..less inclined to pop out of the column as it was doing in its broken state.  I will report back with the solution once that comes to pass.... Thanks again for prompt and expert input!

John Weiland wrote:This brick (photos below) is from a Serbian-made woodstove imported into the US.  When whole, the brick is about 14 inches long.  Because of the narrow dimensions of the brick, I'm not sure if there is a cement or glue that can fuse the two pieces together to be a strong as new??.......  A local woodstove supplier did not have brick of that length to cut down, so would need to custom order which might be pretty expensive.  I've reached out to the US importer to see of they have a stash of bricks for these stoves, but have not heard back from them yet.  Opinons as to whether this could be repaired?.....and if so, what kind of glue or cement to use for a good bond?  Thanks!

The best option would be to get a bag of castable refractory mix somewhere.
They should have it at a shop that specializes in building stoves, fireplaces, ovens, etc.
Since there are many different types of refractory concrete (depending on the temperature rating, processing methods, etc.), you absolutely need to consult with the seller so they can choose the right type for you.
You should also consult with them on how to make the brick.

John.
If you move the broken brick down, there may be a cheap option to try.
Matt Walker told us about a customer who used an automotive product meant to patch exhaust pipes on his core firebricks.
Although intended for metal, he claimed that this product sealed his cracked brick, and it was still holding fine with no reapplication.
A quick look online shows products from JB Weld Extreme Heat, Permatex, and Walker Exhaust.
I do not remember the exact product, but it was a paste, not a wrap.
Certainly worth a try; the price is right.

I have used JB Weld ExtremeHeat. It's a paste with metallic filler - probably stainless steel powder. It has to be mixed well before using as it quickly separates in the container. I have used it to attach square stainless nuts to stainless frame that I used for mounting my oven doors. Originally I wanted to TIG weld them, but I did not have pure argon at the time and the frame sheet metal was very thin, I decided to glue it. I have sanded and de-greased the glued surfaces first, but it did not hold well when I started screwing the bolts and I needed to reapply more glue. On porous surfaces it may work better. It's rated to 1000 F/530 C,

Thanks for extra responses and expert advice.  Yes, I had seen those high temp adhesives for muffler and exhaust work when poking around for solutions to the problem.  I may still opt for one of those to test on the broken brick still.  Nevertheless, the vendor of the stove did get back to me and we made arrangement for a brick to be cut and sent to me from their brick contractor.  Not cheap, and Cristobal I likely will send you a PM to inquire about the cost of cutting two more replacement bricks in the event of potential future breakages.  It sounded from the vendor like this brick was rather "prone to injury" as he noted having received several along with the original shipment of stoves from Serbia and that supply was now gone.  Always much learned here along with getting problems solved.  Thanks again!....