is all firebrick the same

[sgcsalsero]

Maybe this is a newb question but I bought four bricks to replace broken ones on an 18 mth old insert. Feeling a weight difference, took to a scale. The brick on the right is original and weighs 1lb 11oz. Brick on left is 2 months old and weighs 3 lbs 13 oz. Why the difference, also I am thinking right that I should replace all if the ones I just bought are better quality.

Thanks

 

[SlyFerret]

Hmm... so the new brick weighs more than twice as much? Thats a big difference in density. My first thought would be that a denser material would hold more heat energy for a longer period of time. I'm waiting for some of the other guys to chime in, but it seems the replacement bricks would be more desirable.

-SF

 

[EddyKilowatt]

Industry has many different grades of firebrick for use with all different kinds of process applications ranging from pizza ovens up through blast furnaces. Google around for "firebrick" and "refractories" and "refractory brick", and as I recall you'll turn up some educational reading, or at least a glimpse into a seldom-seen world that helps keep the wheels of industry turning.

I realize that in no way answers your question, though... but I wouldn't call myself qualified to do so. If someone knowledgeable here doesn't step forward, I would consider calling the stove manufacturer for their take on it. I am just speculating here, but I am thinking that the lower-density (lighter) brick might have a higher insulating value (R-value) which would affect (probably improve) the burn properties of the stove somewhat... even while being a bit more fragile than a heavier brick.

The thermal tiles on the Space Shuttle are probably the highest art that the refractory industry has produced... firebrick that is basically about as light as styrofoam yet able to operate at a cherry-red heat. But they can't fly the Shuttle thru even a rain shower or it will damage the brick...

Eddy

 

[Corie]

There are two general types of firebrick (technically three).


(What your stove has) Pumice - Lighter weight, higher insulating properties.



(What you bought) Refractory Cement - Heavier weight, less insulating ability, easier to find. This is the type of firebrick you can usually buy at the hardware store or stove shop.



(Irrelevant) Compressed Vermiculite - Generally used only in some European stoves like Morso, these are fairly light weight and impossible to buy anywhere but from the manufacturer. You don't have these.


Since the pumice bricks are better insulators, you should stick with them if that's what came with your stove. Although its doubtful you'll see a HUGE difference in performance, you should always trying to get the stove loaded with parts that are the same as original.

 

[sgcsalsero]

Thanks Corie, I picked up a few pumice bricks for $3.95 each at a local fireplace shop.

 

[Jimbob]

One thing to consider, the lightweight bricks break a LOT easier. At least that's what I found with the different stoves I had.
When I need bricks in my stove, I'll be using the heavy duty ones in the back of the stove, as they'll take more abuse.

A few years ago I toured the PE factory in Duncan, while there I asked the guy (I wish I could remember his name) if I could use the heavier bricks in my Summit, and he said it wouldn't be a problem.

IIRC, he also said they use the light bricks for 2 reasons:
1) Slightly quicker warmup for lower emissions.
2) Lower shipping costs.