Hard Substance on Firebrick?

[firebroad]

Just curious, I was cleaning out the firebox this morning, and felt considerable resistance with the shovel on the bottom. I was afrait that my firebricks were cracked, and since the stove was cold, I ran my fingers over it and found a rough, hard substance that would not come off easily, did get a small piece that looked like tan gravel. I suspect that the load I purchased from a dealer that was caked with mud baked it either into a glass or a brick-like material and fused it to the firebrick. I am afraid of trying to remove it for fear of damaging the bricks, but it is annoying. Any thoughts?

 

[tcassavaugh]

interesting.....but i don't have a clue as to what that might be. i don't get down to the firebrick but once or twice a year when i clean it up at the end of season. i normally leave a little ash bed for the coals when cleaning it out. doubt it is anything serious. close the doors...you'll never notice it

cass

 

[ScotO]

Its hard to say, FB. Some refractories are cast in big pieces to fit a stove, what model stove are we talking about here? My NZ3000 has cast refractories, not bricks.......sounds like that possibly could be the case here. Or possibly you have some clinkers developing in your firebox. What kind of wood are you burning?

 

[firebroad]

Tcass, I notice it eveyrtime I clear out the ashes!

Scotty, I have a PE Alderlea T5 insert. The refractories are bricks, which of course makes them cheaper to replace, but they are still pricey. Not sure what a "clinker" is, the wood may have been oak, but with that dealer i found a lot of other stuff in there, maple, pine, even some tulip poplar!

 

[tcassavaugh]

clink·er
[ klíngkər ]

1. ball of coal residue: a hard mass of ash and partially fused coal that remains after coal is burned in a fire or furnace
2. hard brick: an overhard brick that has been fired in a kiln for too long
3. form lumpy burned residue: to form hard lumps of ash and partially fused coal after burning

.....kind of like left overs.....just a hard mass that doesn't burn down and is hard like a rock.

i don't think that you would have to replace them unless they cracked......i have brick in my summit downstairs but have a grate in my little jotul upstairs.

cass

 

[firebroad]

I am just concerned that I will gouge or crack the brick by the scraping action of the shovel. I wonder if I could try to sand it smooth? Do you think that would do more harm than good?

 

[tcassavaugh]

I'm not sure that it would harm it, but is it necessary to remove it? if its a clinker or is just a rough spot and not large i think i'd just work over it and let it remain unless it starterd getting bigger. if is the size of a gumball, i'd probably try and knock it off. try using a brush to get the remaining last bit of ash off the bricks rather than the shovel....at least that way you're not gouging the brick when you clean it. do you have an ash drawer or are you just scooping into an ash bucket? Just wondering, not that it really matters....using the brush might be less aggravating and noticeable to you.
jmho

cass

 

[firebroad]

Yeah, its a good size--not just one chunk, more like several, about 2-3 inches across. I did use the brush. No ash drawer, I just scoop the fine ash into the bucket.

 

[tcassavaugh]

........not being funny, but.....can you flip the brick over? you might try that. it might do the trick for now. at least you won't notice it. if it happens again, it must be something in the wood. just a thought........

cass

 

[firebroad]

Thought about that. Wasn't sure it would lay flat. An option, I guess...

 

[tcassavaugh]

might they fit on the sides? that might be an option. you might try just a thin layer of ash to set them in, on the bottom if they don't lay flat.
good luck.

cass

 

[firebroad]

might they fit on the sides?.

cass

Gol-darn. Okay, let me get my coffee and wake up. Thanks, cass!
Of course, I still don't know what it is. I am going to wait and see if subsequent fires will vaporize it first. Tonight doesn't count, it's supposed to be so warm today.

 

[ScotO]

As long as the bottom of the stove isn't exposed, it won't present a problem. I'd think aboutchipping the high spot off with a chisel or screwdriver, as it sounds like its more of a nuisance than anything. I think you'd also be fine just leaving it the way it is, if you can. Doesn't hurt to ask, though. At least it shows you pay attention to your stove, and that's a good thing to do!

 

[tcassavaugh]

firebroad, let us know how it works out for you.....its like scotty said, its more of a nuisance than a problem. have fun.

cass

 

[firebroad]

Cass, I will let you know by the weekend. I think tonight I will try to sand it off with some course emery paper. Probably be no fire, as warm as it is today!!

 

[tcassavaugh]

there you go....yup, sure is warm its about 66 up on the roof where my weather station is. just got back from a motorcycle ride to and from the store. plan on riding it to work tomorrow at a quarter to light.....supposed to be warm overnight, not getting much below 50 here in Calvert county Md.

cass

 

[firebroad]

Yeah, amazingly, we had a frozen fog here in Finksburg the other night (beware the Pogonip!)

 

[DexterDay]

Yep.. Its a clinker. More commonly found in Pellet stoves, Corn stoves, or Coal stoves. But not limited to just them.

I get them in my Woodstove too. Its a result of several different things. Temp, moisture, sodium, etc.

The ash bed was likely un-stirred or un-touched where you found this "Mass".

 

[clemsonfor]

if it bugs you that much take a grinder and cut it of, or just replace the brick for $2?

 

[Backwoods Savage]

Hey Sue, this does not sound like much of anything and by the size you say it is, I'd bet it would come loose just scraping with the ash shovel. Or if you have a chisel and small hammer, a light tapping should make it come right off.

As for flipping the brick, I would not because it would not sit right on the bottom. It needs to come off or just leave it on and forget about it. I doubt that would do any harm.

 

[firebroad]

Okay, I did manage to get it scraped off. However, in doing so, since I had to get up close and personal, I discovered a few chips on the corners of one of the the bricks. Of course it is the cut brick. They aren't that serious, I think, but at least i am aware of it. I will get my chimney guys to order new for when they clean me. I have a feeling that previous scraping across the lumpy bits might have done it, but who knows. Thanks everyone. I know some thought I was all in a tizzy but I did not consider it a problem, I was just curious what it was.

 

[madison]

I get the same thing in my T6, around the area of the ash chute and "dog house". This is also the area where my firebrick deteriorates each yr. Sometimes a chunk ~ 1/2 inch thick and a inch or so in diameter will peel off when cleaning out the stove.

My personal theory is it is from a small amount of air that leaks into the stove, via the bolts that hold down the ash chute, as well as the ash chute itself. the rest of the theory - which I have not convinced myself - is it is normal humidity from this entrained air - that for some unknown reason, causes the firebrick itself to slowly deteriorate and form this hard, almost like coal/rock like chunks. Another theory of mine is that this stuff is dirt/sand etc from the wood, that consolidates/fuses in this very hot area of the stove.

I purchased some of the heavier firebrick, which in the future I will use in the area this occurs.

In the meantime, at the end of each season, the firebricks in and around the ash chute and "dog house" that deteriorate get flipped, and rotated to other parts of the stove - ie rear corners.

This has happened every yr

 

[firebroad]

I get the same thing in my T6, around the area of the ash chute and "dog house". This is also the area where my firebrick deteriorates each yr. Sometimes a chunk ~ 1/2 inch thick and a inch or so in diameter will peel off when cleaning out the stove.

My personal theory is it is from a small amount of air that leaks into the stove, via the bolts that hold down the ash chute, as well as the ash chute itself. the rest of the theory - which I have not convinced myself - is it is normal humidity from this entrained air - that for some unknown reason, causes the firebrick itself to slowly deteriorate and form this hard, almost like coal/rock like chunks. Another theory of mine is that this stuff is dirt/sand etc from the wood, that consolidates/fuses in this very hot area of the stove.

I purchased some of the heavier firebrick, which in the future I will use in the area this occurs.

In the meantime, at the end of each season, the firebricks in and around the ash chute and "dog house" that deteriorate get flipped, and rotated to other parts of the stove - ie rear corners.

This has happened every yr

Interesting! Thanks for the input. Although I do not have an ash chute, the area is closer to the front, about4-5 inches from the door. Didn't happen last year, but I was burning "cooler" (greener) wood. Also, I burn nights and weekends only, so the bricks are probably being "shocked" by the sudden change in temp.

 

[madison]

The t-6 ash chute is located ~ 4 -5 inches from the front, just left of center. So the build up is generally in the same area. Part of the theory (part b) is I rake everything to the front center into a mound each time I reload, and the "cake" buildup is under this mound.

 

[begreen]

I get clinker build up too, mostly in the center of the stove. I think this is due to the boost manifold output fusing the silicas in the wood and perhaps enhanced by the pumice brick's higher insulating value. And probably because I burn some thick bark on some splits, especially fir and locust.

Use the ash shovel to get under an edge of the clinker and then lever the clinker up. It should rise in one or two pieces. That will prevent gouging the brick. I have pulled 8-10" clinkers out this way without harming the brick.