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With a lot of inspiration (EADavis's Forno Clamshell, the Little Black Egg mentioned both here and at pizzamaking.com, and the pizzahacker Franken-Weber that made the rounds a few months ago) I've decided to give a grill conversion a go.
There seem to be a broad range of opinions on how these things should work: propane vs wood-fired (with pizzahacker being the only one I've found opting for wood). Insulated (Forno Clamshell and FrankenWeber) vs letting the propane do the work (most of the little black eggs). Radiant vs convective heating to cook the tops of the pizzas (everyone probably falls somewhere a little different on a sliding scale). Side vs top venting. Etc.
My initial desires/design considerations are:
Big: I'd love to be able to cook an 18"-20" pizza.
Lots of BTUs: For minimal time to get from startup to operational temp
Heavily insulated: Both to be stingy with propane and to keep it at operational temp without too much work.
Thermal mass in the top: Because it just feels inauthentic to me if there isn't some heat radiating down from the dome onto the pizza. So what if this project is already super-inauthentic. :-)
Picked up a 22.5" Weber, cheap, from Craigslist. Shouldn't have too much trouble lobotomizing it and affixing a propane burner. Found a cheap high pressure cast iron burner at Academy -- still need a good regulator to pump out the maximal heat.
Also found a 21" cordierite kiln shelf at a reasonable price; laid it in the grill and it looks like it was made for it -- though it is a bit of a tight fit in terms of getting good air circulation. Might have to get a tileworking friend to open up some space on one side. I'll be using a round cast iron griddle
Here's where things get a little more hazy for me. I am a complete newbie to all of this, but I've read quite a bit in the last few days, and here's my thinking:
Insulation: I would like to line the entire assembly with ceramic blanket. Seems it can be affixed to the walls of the grill with Resbond 907GF. Or... could I just feather some sort of mortar in to affix it to? Is there a thinset that can handle the temperatures?
Then I'd need to cover it to keep bits from flaking off and giving my guests silicosis. People generally seem to suggest ITC HT 100 Ceramic coating, but others have mentioned covering with refractory mortar. I know this is completely backwards from the point of view of most oven-builders here, but do you think I could put together a homebrew* mortar to seal in the blanket without compressing it and killing its insulative properties? As I've not worked with any mortar/cement before (seriously, total noob) I don't have a good sense for whether these two materials would play nice together.
The other option is just to cover the blanket with heavy duty aluminum foil. Somehow seems like a bit of a cop-out, and less durable. But I don't think any part that's covered in foil will be nearing the melting point of aluminum, so that should hold up.
Top: Long term: I'd love to build a top like pizzahacker's. I haven't contacted him (though I probably should), but I assume the method to do that would be (if someone corrects any glaring problems, I will be very grateful):
Line the weber top with newspaper (?) or saran wrap (?). Make a fairly strong vermicrete mix (3 or 4:1 ratio?) to minimize crumbling. Fill the weber top, using a large bowl to form a dome shape on what will be the underside. Let cure for a few days.
Coat the inside of the vermicrete layer with a layer of refractory mortar. (Am I way off base here? Will it hold together? Will it handle the hopefully 900-1000 degF temps without losing integrity?)
Coat the outside of the vermicrete layer with something (more refractory mortar?) to smooth and parge (?) it. (Is that even a verb?)
Cast a C-shaped stand on which the dome will sit, with an opening at the front for pizza loading. (Like a first course of bricks, but thinner and made of something castable -- wish I could homebrew that.)
With everything miniaturized, there's going to be a lot more heat escaping through the entirety of the dome -- will the portland cement break down? Clearly it can be done, since I've seen video of it being done -- I'm just not quite sure of how, or whether my ideas are flawed.
Top: Short term: line the top with foil (with ceramic blanket underneath, when I manage to get some), somehow bolt a big kiln shelf to it.
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Wow. I sure can ramble on. My thanks and apologies if you read all of that.
I don't have any pictures yet, but I've got many of the pieces together, so hopefully there'll be something to look at within the week. If I can get the burner attached and the propane tank filled, there might even be shots of it in use.
Any thoughts? Ideas? Accolades? Dire warnings? I am listening. Cheers.
--------
* Can't seem to find the premixed in anything less than expensively large quantities.
PS. I tried to post this last week, but it got lost somewhere in the tubes. If a 2nd copy of this shows up, I apologize.
There seem to be a broad range of opinions on how these things should work: propane vs wood-fired (with pizzahacker being the only one I've found opting for wood). Insulated (Forno Clamshell and FrankenWeber) vs letting the propane do the work (most of the little black eggs). Radiant vs convective heating to cook the tops of the pizzas (everyone probably falls somewhere a little different on a sliding scale). Side vs top venting. Etc.
My initial desires/design considerations are:
Big: I'd love to be able to cook an 18"-20" pizza.
Lots of BTUs: For minimal time to get from startup to operational temp
Heavily insulated: Both to be stingy with propane and to keep it at operational temp without too much work.
Thermal mass in the top: Because it just feels inauthentic to me if there isn't some heat radiating down from the dome onto the pizza. So what if this project is already super-inauthentic. :-)
Picked up a 22.5" Weber, cheap, from Craigslist. Shouldn't have too much trouble lobotomizing it and affixing a propane burner. Found a cheap high pressure cast iron burner at Academy -- still need a good regulator to pump out the maximal heat.
Also found a 21" cordierite kiln shelf at a reasonable price; laid it in the grill and it looks like it was made for it -- though it is a bit of a tight fit in terms of getting good air circulation. Might have to get a tileworking friend to open up some space on one side. I'll be using a round cast iron griddle
Here's where things get a little more hazy for me. I am a complete newbie to all of this, but I've read quite a bit in the last few days, and here's my thinking:
Insulation: I would like to line the entire assembly with ceramic blanket. Seems it can be affixed to the walls of the grill with Resbond 907GF. Or... could I just feather some sort of mortar in to affix it to? Is there a thinset that can handle the temperatures?
Then I'd need to cover it to keep bits from flaking off and giving my guests silicosis. People generally seem to suggest ITC HT 100 Ceramic coating, but others have mentioned covering with refractory mortar. I know this is completely backwards from the point of view of most oven-builders here, but do you think I could put together a homebrew* mortar to seal in the blanket without compressing it and killing its insulative properties? As I've not worked with any mortar/cement before (seriously, total noob) I don't have a good sense for whether these two materials would play nice together.
The other option is just to cover the blanket with heavy duty aluminum foil. Somehow seems like a bit of a cop-out, and less durable. But I don't think any part that's covered in foil will be nearing the melting point of aluminum, so that should hold up.
Top: Long term: I'd love to build a top like pizzahacker's. I haven't contacted him (though I probably should), but I assume the method to do that would be (if someone corrects any glaring problems, I will be very grateful):
Line the weber top with newspaper (?) or saran wrap (?). Make a fairly strong vermicrete mix (3 or 4:1 ratio?) to minimize crumbling. Fill the weber top, using a large bowl to form a dome shape on what will be the underside. Let cure for a few days.
Coat the inside of the vermicrete layer with a layer of refractory mortar. (Am I way off base here? Will it hold together? Will it handle the hopefully 900-1000 degF temps without losing integrity?)
Coat the outside of the vermicrete layer with something (more refractory mortar?) to smooth and parge (?) it. (Is that even a verb?)
Cast a C-shaped stand on which the dome will sit, with an opening at the front for pizza loading. (Like a first course of bricks, but thinner and made of something castable -- wish I could homebrew that.)
With everything miniaturized, there's going to be a lot more heat escaping through the entirety of the dome -- will the portland cement break down? Clearly it can be done, since I've seen video of it being done -- I'm just not quite sure of how, or whether my ideas are flawed.
Top: Short term: line the top with foil (with ceramic blanket underneath, when I manage to get some), somehow bolt a big kiln shelf to it.
--------
Wow. I sure can ramble on. My thanks and apologies if you read all of that.
I don't have any pictures yet, but I've got many of the pieces together, so hopefully there'll be something to look at within the week. If I can get the burner attached and the propane tank filled, there might even be shots of it in use.
Any thoughts? Ideas? Accolades? Dire warnings? I am listening. Cheers.
--------
* Can't seem to find the premixed in anything less than expensively large quantities.
PS. I tried to post this last week, but it got lost somewhere in the tubes. If a 2nd copy of this shows up, I apologize.
Actually, thank you - the whole reason I posted my experience was to get people thinking about other ways to cook pizza.
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