New KJ Firebox Design

JustineCaseyFeldown

JohnInCarolina said:

This is largely correct, except in your last paragraph regarding the "least dimension."  In brittle materials, the direction of fractures is largely dictated by the orientation of the maximum tensile principal stress component.

The complexity of the shape also isn't the issue here so much as the constraint provided in the circumferential direction of a contiguous piece.  That's what gives rise to tensile principal stresses under a thermal gradient.

re: "This is largely correct, except in your last paragraph regarding the "least dimension."   I was talking specifically about sidewalks here as a simple practical every day example...  whether or not a sidewalk (again, as a practical example of a poured and generally inflexible material) is reinforced by welded wire fabric and maybe some entrained fiber, it's fairly pretty homogeneous in both directions. ...until you make it longer than wide. that's when there's a different orientation despite its being homogenous, for the most part. 

yes, there are other considerations for a slab on grade... but  it isn't really germane to this discussion. 99.99 percent of the time, a three foot wide sidewalk (poured without tooled joints) will crack not only across the three foot dimension (as opposed to down the middle in the long dimension), but it will even tend to crack roughly every three feet.  a four foot wide sidewalk tends  to crack every four feet. 

w/r/t the complex shape.... a curve in two directions, like the one-piece firebox, gives you different amounts of expansion across the piece, the gradient' you refer to.  the one piece box has changing radius dimensions in two directions.  not sure why that wouldn't contribute to "constraint provided in the circumferential direction of a contiguous piece".  more than one of those curves isn't expanding as the same rate as the others, no?  isn't the the perimeter of the firebox rim expanding greater than the convex belly of the firebox lower down?


regardless, wasn't going for a deep dive here. i try to keep things relatable omn a practical level, rather than try to win a footnote war. 

simply trying to explain that the reason KJ fired it in multiple pieces is because a one-piece ceramic firebox of that shape will always tend to break along those stress lines anyway, and they are beating it to the punch.  in our case, usually from hole-to-hole in a circumference, and then into pie shaped wedges, as the stresses try to turn this thing into stable shapes that don't expand (as) differently across their volume. 

in fact, if the KJ firebox breaks at all, i'd bet money it will be at the holes of the wedge pieces, across to the nearest edge

JohnInCarolina

@JustineCaseyFeldown

That's fine about sidewalks, but the relative size of a component in one direction vs another, in and of itself,  has fairly little to do with the fracture patterns that form.  The fractures care about the local state of stress, not which direction is shorter to grow in.  If we tend to see patterns along smaller directions than others it is because that aspect of the geometry is what is adjusting the stress state.  I can provide plenty of counterexamples here.  

Concerning the constraint, the issue I was referring to is that the surrounding material isn't providing a free surface (in the circumferential direction), that is traction free, which would help to limit the extent to which the tensile normal stress can become sufficiently large on the interior.  The confinement that is provided in the direction that is perpendicular to the orientation of the thermal gradient is what matters here.  The change in curvature from bottom to top probably does give rise to some additional stress, sure, but the thermal gradient in the vertical direction doesn't appear to be as large.  Otherwise we'd expect to see more planar cracks in these components.  

So much for keeping things relatable on a practical level, right?    I'm not trying to "win" anything by the way, just sharing my knowledge of fracture mechanics.  

In any case, I agree that the KJ design will probably reduce the likelihood of additional fractures forming.  Although I've never viewed one or two cracks as being all that problematic.  Replacing these things simply because they have a couple of cracks is kind of silly - they still function just fine.  

Legume

Smarty-pants arguments use lots of ink.

Big_Green_Craig

Kudos to KJ for continuing to be innovative with their products. They've got some other stuff in the works as well. 

Their new hinge design is very interesting. There is zero weight to the dome. Anxious to see how that works in the long term. 

yljkt

BGE has changed the banner on this site like twice in the last month. The innovations are coming, relax.   

Canugghead

Darn, just bought an uuni and spent my 'allowance', no chance I can justify a redesigned KJ Jr. at the next roadshow 

bigbadben

Canugghead said:

Darn, just bought an uuni and spent my 'allowance', no chance I can justify a redesigned KJ Jr. at the next roadshow 

I think the vent caps and hinges are classic and BigJoe only. The jr will eventually get gaskets and FB. 

bigbadben

HeavyG said:

I'm guessing they decided not to go with the cast iron fire boxes they had prototypes of a few months ago.

Their new cantilevered hinge is going to be sweet on their Big Joe. Their new vent cap will be nice also. Hopefully all these improvements will be available this summer.

I think I saw a post somewhere, the CI parts are heavy.  I bet they don't crack...

Ozzie_Isaac

@JohnInCarolina and @St!ke thank you for the cogent discussions.  It made my heart happy.

SoCalTim

A local KJ dealer told me, KJ is thinking of having several Eggfest style get-togethers in 2018 and call them 'Joe-fests' .. boy' they sure are getting aggressive.

HeavyG

JohnInCarolina said:

Maybe next they'll design a forum that doesn't suck.

Well...the "official" KJ forum doesn't suck per se, it's just pretty empty. It's as if nobody knows it's there. 

What's really odd is that the head of the KJ company occasionally posts and informs folks of things going on with KJ over on the kamadoguru.com forum rather than his own KJ forum. KJ has also hired a fellow that was a kamdoguru.com regular and who has been recently asking folks there for ideas on some new things KJ is developing (they're kicking around a neat new cart idea at the moment) and has not also done that over on the "official" KJ forum. 

Canugghead

@bigbadben thanks for the info, I can start working on 2018!

HeavyG

bigbadben said:

HeavyG said:

I'm guessing they decided not to go with the cast iron fire boxes they had prototypes of a few months ago.

Their new cantilevered hinge is going to be sweet on their Big Joe. Their new vent cap will be nice also. Hopefully all these improvements will be available this summer.

I think I saw a post somewhere, the CI parts are heavy.  I bet they don't crack...

As expected they would be pretty heavy. If I remember correctly tho the prototype for the Big Joe was made of three separate pieces so each piece wouldn't be too heavy for most folks to deal with.

JohnInCarolina

HeavyG said:

JohnInCarolina said:

Maybe next they'll design a forum that doesn't suck.

Well...the "official" KJ forum doesn't suck per se, it's just pretty empty. It's as if nobody knows it's there. 

What's really odd is that the head of the KJ company occasionally posts and informs folks of things going on with KJ over on the kamadoguru.com forum rather than his own KJ forum. KJ has also hired a fellow that was a kamdoguru.com regular and who has been recently asking folks there for ideas on some new things KJ is developing (they're kicking around a neat new cart idea at the moment) and has not also done that over on the "official" KJ forum. 

Yeah that was mostly a joke. I've never been to the KJ forum, but I guess I'm not surprised it isn't all that busy.  

I'm not surprised the head does that.  That kamadoguru.com forum is probably the best means for him to get the word out on new stuff.  I mean, it's not like he needs to post anything here...

saluki2007

My fire bowl cracked horizontally and not vertically:


Is mine special?  My fire ring however did crack vertically:

JohnInCarolina

@saluki2007 I don't know if I'd characterize it as "special," but the pattern you saw in your fire bowl is likely to be very similar to what the new KJ designs will exhibit.

You'll notice that the BGE fire bowl has a vertical gap in it already, which provides stress relief (circumferentially), whereas the current KJ firebox does not.   

bigbadben

JohnInCarolina said:

HeavyG said:

JohnInCarolina said:

Maybe next they'll design a forum that doesn't suck.

Well...the "official" KJ forum doesn't suck per se, it's just pretty empty. It's as if nobody knows it's there. 

What's really odd is that the head of the KJ company occasionally posts and informs folks of things going on with KJ over on the kamadoguru.com forum rather than his own KJ forum. KJ has also hired a fellow that was a kamdoguru.com regular and who has been recently asking folks there for ideas on some new things KJ is developing (they're kicking around a neat new cart idea at the moment) and has not also done that over on the "official" KJ forum. 

Yeah that was mostly a joke. I've never been to the KJ forum, but I guess I'm not surprised it isn't all that busy.  

I'm not surprised the head does that.  That kamadoguru.com forum is probably the best means for him to get the word out on new stuff.  I mean, it's not like he needs to post anything here...

What do you bet he is watching?  He posts his email all over the web.  I bet he would be open to talking grills with anyone who reached out. 

dgaddis1

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

Photo Egg

dgaddis1 said:

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

I bet the KJ dealer that is super happy dealing KJ is not living next to a Costco who runs a KJ Roadshow 3-4 times a year under selling his store prices.
Hard for a dealer to stay in business competing against a KJ Factory sponsored event.
Not saying BGE has been any better letting their product "leak" into Sam's Club all the time.

bigbadben

Photo Egg said:

dgaddis1 said:

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

I bet the KJ dealer that is super happy dealing KJ is not living next to a Costco who runs a KJ Roadshow 3-4 times a year under selling his store prices.
Hard for a dealer to stay in business competing against a KJ Factory sponsored event.
Not saying BGE has been any better letting their product "leak" into Sam's Club all the time.

While I know it sucks for dealers, atleast KJ is open honest and warrenties the grills sold at Costco.  BGE just ignores the pallets of grills that magically appear at Sams. 

pgprescott

I will say that there is a lot of activity over there. This could be interpreted many different ways I suppose.

 I don't really have issue with the hinges on any of the Kamados. I also don't have a problem with the new gaskets. The one in the KJ pic looks similar to the Weber one. The divide and conquer is the bests innovation IMO, but you can do these thing with the egg too. In fact it's just a rip off of some stuff that is available either through BGE or the aftermarket. Granted, they are extra. The Joetisserie seems kinda cool I guess. The nest for the KJ looks much less stable and i don't see any "handler" with theirs. To me, sure the innovations are great, but its much to do about nothing. The prices are about the same @ here. I also feel Egg and the ancillary vendors for the egg drive the market, including most of the innovations. I just don't see anything that is even close to a game changer for me, personally. The new Weber summit grill is way cooler IMO. Like BB Maniac says, its his favorite unit. Note he has a Kamado Kamado and eggs etc..

dgaddis1

Photo Egg said:

dgaddis1 said:

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

I bet the KJ dealer that is super happy dealing KJ is not living next to a Costco who runs a KJ Roadshow 3-4 times a year under selling his store prices.
Hard for a dealer to stay in business competing against a KJ Factory sponsored event.
Not saying BGE has been any better letting their product "leak" into Sam's Club all the time.

As someone in retail, I know all too well the pains and frustrations with trying to compete against prices below my costs.

Photo Egg

bigbadben said:

Photo Egg said:

dgaddis1 said:

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

I bet the KJ dealer that is super happy dealing KJ is not living next to a Costco who runs a KJ Roadshow 3-4 times a year under selling his store prices.
Hard for a dealer to stay in business competing against a KJ Factory sponsored event.
Not saying BGE has been any better letting their product "leak" into Sam's Club all the time.

While I know it sucks for dealers, atleast KJ is open honest and warrenties the grills sold at Costco.  BGE just ignores the pallets of grills that magically appear at Sams. 

I agree about the BGE and Sam's Club and I knew someone would throw it back at me that's why I put it in my post.

And of course KJ honors the grills sold at Costco...they sponsor the event...that's my exact point...they undercut their own dealers.

Hans61

As an egg owner I'm not in the market for another kamado. If you only have one egg and no other grill, a simple cheap dependable Weber kettle makes a fine companion for a kamado 

stlcharcoal

dgaddis1 said:

Photo Egg said:

dgaddis1 said:

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

I bet the KJ dealer that is super happy dealing KJ is not living next to a Costco who runs a KJ Roadshow 3-4 times a year under selling his store prices.
Hard for a dealer to stay in business competing against a KJ Factory sponsored event.
Not saying BGE has been any better letting their product "leak" into Sam's Club all the time.

As someone in retail, I know all too well the pains and frustrations with trying to compete against prices below my costs.

Here in STL they have a dealer within walking distance to Costco.  Couple summers ago that dealer had backorders for KJ's, yet they were available at Costco for just a little over their dealer cost.  They considered going across the street to buy every single one at the RoadShow just to fulfill their orders, but then mysteriously those orders were cancelled about the same time.  Wonder where those customers bought their KJ's?  They called to complain and were told that that particular Costco wasn't supposed to be on the list because of the proximity......yet their rep was staffing the booth. 

But like someone else said, since BGE won't honor the warranties on the Sams/Costco ones, they go in and buy them back in order to protect their dealers.  That's what I would do if my product ever showed up there.

dgaddis1 said:

BGE had seriously better watch out.  I've talked to several dealers who recommend the KJ over the Egg, and I know one who dropped BGE because warranty issues were more frequent and a much bigger hassle.  If I were buying a grill today I'd go red.  Only reason I have an Egg is because it came with the house we bought last year...but after having one, I don't ever want to live without a komodo grill again!!

As a BGE dealer, you're not allowed to have any other kamados for sale.  There are so many others at better price points and margins, some are seeing the opportunity to jump ship and bring in multiple other brands.  You also have to maintain a BUNCH of the eggessories, which not everyone wants to mess with--especially since Smokeware, CGS, and other companies all make better ones now.

dgaddis1

stlcharcoal said:

As a BGE dealer, you're not allowed to have any other kamados for sale.  There are so many others at better price points and margins, some are seeing the opportunity to jump ship and bring in multiple other brands.  You also have to maintain a BUNCH of the eggessories, which not everyone wants to mess with--especially since Smokeware, CGS, and other companies all make better ones now.

I've seen BGE and KJ available for sale side by side several times, and sometimes others as well, like Primo. In fact I don't think I've ever seen anywhere that carried BGE and not also KJ.  I've only been paying attention for about a year though.

It's lame when manufacturers try and restrict their dealers to only carrying their product.  If one of my manufacturers had that requirement I wouldn't carry their stuff, that's for sure.

chuckytheegghead

In my opinion, the new gasket is pretty sweet. The firebox, couldn't care less- it doesn't the way it cooks and will be warranty anyways. The cap is a rip off of the smokeware cap but looks silly. I just don't understand the new hinge. I've never had the need to leave my dome open just ever so slightly. Sorry guys I just don't see what all the fuss is about. 

HeavyG

chuckytheegghead said:

In my opinion, the new gasket is pretty sweet. The firebox, couldn't care less- it doesn't the way it cooks and will be warranty anyways. The cap is a rip off of the smokeware cap but looks silly. I just don't understand the new hinge. I've never had the need to leave my dome open just ever so slightly. Sorry guys I just don't see what all the fuss is about. 

Not everybody has Popeye arms and the dome of a Big Joe or XL is rather heavy. The cantilevered hinge also prevents the dome from slamming shut and can be opened with a couple fingers.

I'm also betting that it is a much sturdier hinge assembly and will lessen problems with alignment.

Win win to me.

Wolfpack

Photo Egg said:

JohnInCarolina said:

Maybe next they'll design a forum that doesn't suck.

How many years did it take BGE to take over and run their own forum?

Different time- Gore hadn't even invented the internet with the egg was created. 

chuckytheegghead

Was that an issue with the Joe? I've never had an issue with the domes slamming down on any of my egg.