DennisLinkletter Posted April 15, 2007 Report Posted April 15, 2007 Basic thermodynamics and physics dictate that all matter expands when heated.. Ain't no getting around that. Although the dense inner layer is rated for continuous exposure to 2,200ºf it will expand starting at about 800-1,000ºf. As it expands it creates small hairline fractures. These fractures close when the cooker cools and are only in one of two layers but never the less cause concern with customers who have seen their one layer ceramic cookers crumble from this. My solution to this inevitable expansion is to build into my Komodo a small expansion joint. When heated to high temperatures the body expands and the small joints move and then move back. No harm, no foul.. Another Komodo first..
ThreeDJ16 Posted April 15, 2007 Report Posted April 15, 2007 Very cool (or rather hot) idea. People have used expansion joints in masonry work for years, so why not ceramics! -=Jasen=-
Sanny Posted April 15, 2007 Report Posted April 15, 2007 Wow... nice solution to a customer concern. Fish gotta swim, pigs gotta fly, and ceramic's gotta expand. Good idea! Thanks, Dennis! Got any way to plug up a mud volcano?
PaulR Posted April 16, 2007 Report Posted April 16, 2007 I'm a complete newbie at building anything however have some questions: wouldn't the expansion joints weaken the structure of a fairly heavy BBQ? would the heat "seeping" through these expansion joints "damage" the outer layer? PS These questions are because I am clueless re building stuff so please be gentle when flaming me...
Firemonkey Posted April 16, 2007 Report Posted April 16, 2007 The joints do not (at least to begin with) go all the way through the first layer. Typically, an expansion joint is simply a groove that will become "the weakest link" when the material gets to the point of needing to crack. This way, rather than having hairline cracks running freeform around the dome, they will be constrained to the grooves provided. So there is no gap to allow heat to seep out. You have to remember that the cracks these joints are intended to counter only appear when the material is hot and has expanded. When the material cools, everything contracts again and they tighten up. There is reinforcing material inside of the substrate to keep everything held together.
DennisLinkletter Posted April 17, 2007 Author Report Posted April 17, 2007 Puurfect answer from the Monkey.. Right on the money answer.. Could not have said it better myself..
jiarby Posted August 16, 2008 Report Posted August 16, 2008 So do you cut these with something like a box knife while the mix is soft.. then fire it? Are they fired at all??
DennisLinkletter Posted August 17, 2008 Author Report Posted August 17, 2008 Don't need all our tricks to be posted online So do you cut these with something like a box knife while the mix is soft.. then fire it? Are they fired at all?? Yes, they are cut with something but not like a box knife (If you really gotta know, pm me and I'll give you a call and explain how it's done.. Don't need all our tricks to be posted online..) The cookers are heated but not fired. This not a traditional ceramic that requires firing but between 800- 1,000º there is some type of bonding or change that takes place and it gets much stronger.. It's Sunday morning and my pre-coffee brain can't find the term I'm looking for but it's a well know trasnformation.. BTW KOmodos are heated a total of about 20 hours during different stages of production.
U2PLT Posted August 17, 2008 Report Posted August 17, 2008 Thermoplactic Set Point I would guess that your material has a natural thermoplastic set point that requires it reach a certain temperature to occurr.
johnnyboy Posted August 28, 2008 Report Posted August 28, 2008 Thanks for the detailed explination Dennis. I like it!! The low number before expansion even starts is already HOTTER than needed for any cooking I do.
