Effects of high-flow aftermarket fire grates

stlcharcoal

CanDid said:

RRP said:

CanDid said:

Remember, the firebox has a slit in it so that it can expand and contract without cracking. The base does not.

Help me understand how a ceramic fire box expands when heated.

I can't tell if you're being serious or not, but it's called thermal expansion. Look it up. You can start on the BGE website where they state, "This cut allows for repeated heat expansion and contraction without putting stress on the ceramics."

They didn't start putting that cut in there until about 5-6 yrs ago.  It was a solid firebox for 35+ yrs.  There are plenty of fireboxes still cracking, so the cut didn't really solve the problem.  That being said, there are a lot more Eggs in the last 5-6 yrs, so it's hard to track.......but every firebox I have warrantied this year has had the cut in it.

Eggcelsior

RRP said:

CanDid said:

Remember, the firebox has a slit in it so that it can expand and contract without cracking. The base does not.

Help me understand how a ceramic fire box expands when heated.

Determine the coefficient of thermal expansion based on temp and pressure. Then you'll know. It's not much, but most everything has some degree of expansion.

Skiddymarker

HeavyG said:

Methinks the impact (if any) of radiant heat from a KAB (or other grate) would rapidly diminish once even a thin layer of ash settles onto the base.

Which is why I always leave a layer of ash in the bottom of the egg, same as in the bottom of my air-tight woodstove. The ash protects the fire bricks and base, eggs and wood stoves do not need to be vacuumed, ever, IMO.
Primo uses a ceramic plate about the same size as the fire grate that is raised just off the floor of the base. The falling embers are on top of the ceramic "plate", not on the floor of the base. Fire grate in Primo uses oval holes that do not seem to plug as much as the round BGE holes. 

theyolksonyou

HeavyG said:

I use my KAB sans original grate. I just don't buy the notion that little embers have enough energy to harm the ceramic base (which is likely kiln fired at over 2000°F).

Roughly 2450 F

CanDid

@stlcharcoal,  Perhaps they've changed their ceramic mixture or production method to cut costs? Certainly a possibility. But my main objective was to point out that, although on a very small scale, ceramics do expand and contract.

Botch

CanDid said:

...my main objective was to point out that, although on a very small scale, ceramics do expand and contract.

Yes, and likewise, they have correspondingly less ability to "flex", or accomodate, that expansion/contraction.  
  

Focker

Tables have been burning with or without a basket for years.

I know we've covered this before...
The off and on heat, not necessarily high heat, maybe 300, 400 degrees..breaks the wood down over time, making it more combustible, eventually leading to the burn marks. 

It's not a few falling embers.  The high heat is above that.

Best thing I did eggwise was get rid of my wood table.

cookingdude555

All of my fireboxes were cracked and replaced under warranty before getting a KAB or hique (I use both in a cross hatch pattern). They will eventually crack again, and I wont be blaming the new method that wasn't there the first time they cracked.

SSQUAL612

RRP said:

Another vote for removing the grate when switching to a KAB. The wide open air flow allowed by the design of the KAB is why I went that route! I mean...why hamper the air flow? 

They recommend  using the stock grate with the KAB on the XL.
https://ceramicgrillstore.com/collections/kick-ash-basket/products/kick-ash-basket-bge-xl

HeavyG

SSQUAL612 said:

RRP said:

Another vote for removing the grate when switching to a KAB. The wide open air flow allowed by the design of the KAB is why I went that route! I mean...why hamper the air flow? 

They recommend  using the stock grate with the KAB on the XL.
https://ceramicgrillstore.com/collections/kick-ash-basket/products/kick-ash-basket-bge-xl

I'm guessing that has more to do with the shape of their basket for the XL. It has such a large flat bottom that it might need the extra support to keep from warping/deforming with a full load of hot charcoal.

Looking at their pix on the KAB site the plentiful holes of the OEM XL grate are somewhat larger than the gaps in the wire basket so I can't see that any embers falling thru is more of a concern with the KAB.

I don't have an XL (never even looked at one up close in person) but was pleased/surprised by the number/size of the holes in the OEM grate.

Roebuck

I leave the stock fire grate in with my KAB - Having both in place doesn't hamper air flow at all IMO. If anything, the gauge of the KAB wire enhances the air flow. No?

fishlessman

have cracked two large bases and burnt thru a 2 inch thick pine table with just the stock ci grate. with the original ci grate the egg will climb to 1200 degree dome plus/minus, pretty sure thats the same with the KAB. i leave a pile of ash in the bottom of the base now to buffer the heat ........aka laziness and it seems to work

nolaegghead

If you are grilling, no need to open the bottom vent, keep it closed and just leave the lid open.  If you open the bottom vent, the fire dives down, heats the bottom of the egg up more than necessary.  Just throwing this out there.

CanDid

Skiddymarker said:

Primo uses a ceramic plate about the same size as the fire grate that is raised just off the floor of the base. The falling embers are on top of the ceramic "plate", not on the floor of the base. Fire grate in Primo uses oval holes that do not seem to plug as much as the round BGE holes. 

Have not seen that before, but just discovered that Saffire uses something similar too. They call it an "efficiency plate" and claims it reduces heat loss, but it's just a stainless steal plate that sets up a tiny bit off the bottom of the base.

I agree with what @SemolinaPilchard mentioned, about heat radiating down from the fire, and that would explain why a good number of KAB sans firegrate users experienced a cracked base or other unusual occurrence.

Primo and Saffire may be on to something as far as protecting the bottom of the base from extreme heat. I haven't measured my XL BGE yet, but it's possible the L or XL "efficiency plate" may fit an Egg, for all the KAB sans firegrate users out there that might want to add a little extra protection to their base.

bettysnephew

Is the Egg sitting directly on the table? Did not see mention of legs or spacer of any sort but may have missed it in the comments. If it is, you need to isolate it from the wooden table.

OhioEgger

Another data point:
Yesterday I did a cleanup burn in my Large. Up to 700°F for about 15 minutes, and let it gradually die down. I was curious, so I placed the probe of my ET-732 under the Egg, touching the center of the bottom. The Egg sits on ceramic spacers. Even at 700 dome temp, the outside of the Egg's bottom never got above 425°F. I use a KAB with a High-Que grate at 90 degrees beneath it. 

GrateEggspectations

bettysnephew said:

Is the Egg sitting directly on the table? Did not see mention of legs or spacer of any sort but may have missed it in the comments. If it is, you need to isolate it from the wooden table.

Egg sits on the Mini Max carrier, with an air gap between the Egg and the table. 

RRP

bettysnephew said:

Is the Egg sitting directly on the table? Did not see mention of legs or spacer of any sort but may have missed it in the comments. If it is, you need to isolate it from the wooden table.

Howdy stranger! Nice to see you stop by the forum! BTW just this afternoon a shipped a Rutland to a new egger also there in Cedar Rapids.

Canugghead

I recall reading a post long time ago ... someone lined the bottom of the egg with firebricks. 

As for the cut in the firebox, I try to lift it with even pressure on both sides of the cut, the OCD in me figures if helps prevent 'twisting', especially with the weight of XL firebox. Just my 2 cents.