Keystone CRA|CK Ugh!!!!

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Question:
I thought about opening a new thread for this, but, hey... this is basically my build thread, so... The topic is HEAT RETENTION.

1.) How quickly would your oven cool down with no door in place after getting it up to pizza cooking temps?

2.) When heat is retained the best, are the coals left in overnight with the door closed, or are they removed first, THEN close the door?


I still haven't made a door, but when I get close to temperature... which take A LOT of wood!!... I don't notice any heating on the outside of my dome. Except for right next to the flue, it is cool to the touch all over. But, it just seems like the oven cools dramatically after use. I guess I thought it would retain heat better --even without a door!

Thanks in advance for your answers.

[Les]

Re: Keystone CRA|CK Ugh!!!!

Lars - I posted a thread about my oven's retained heat, but it wasn't without the door. I leave my coals in and shut the door. Makes for an easier removal the next day.

Les...

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Okay,
It has been a while since I posted and it was kind of hard to find my thread!

I made a door for the oven!! Just a quick one.

I decided to just make a heavy wooden door from the ends of some 2x6 pieces.

I also made and OUTER door which I may be able to use while heating.

On the inner door, I faced it with a piece of galvanized sheet metal I had, and bent it around all the edges on top and sides.

Hopefully just stopping the air flow will significantly reduce the heat loss after firing. I am so curious to see if my oven retains heat well enough, so... tomorrow night! Pizza and door experiment.

Lars.

[mfiore]

Re: Keystone CRA|CK Ugh!!!!

Any photos?

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Mike,
I haven't taken any pictures of the door. Just a 2x6 pieces with a cross piece to hold them all together, faced with sheet metal.

I put the door on last night after removing all the coals and fire. Starting temp was only about 450. Overnight it dropped to about 200. ( 12 hrs.)

I am sure if I had left the fire in there it would have been a lot hotter, but this is ... o... k...a...y... I guess. What do you guys think?

Did I under insulate?

I shot the exterior of my dome and it was about 82 degrees while surrounding temps were more like 76, but... not sure how accurate or relevant that is.

Lars.

[RTflorida]

Re: Keystone CRA|CK Ugh!!!!

My 12 hr drop off is in the same range about 200-250 degrees. The starting point is usually much higher for me. I do pizza in the evening at 750 plus degrees, let the coals die down and put the door on while it is still 650 degrees (usually around 9-10 pm). At 10-12 the next morning, the temp is usually around 400-425. IF I were to keep the door on and not roast anything, the temp drops about another 100-150 in the next twelve hours. Morning of day three I'm at around 200, where I have to actually started
a small new recharge fire (and to get some usable coals) to bump the temp up 75-100 for smoking. I can then smoke all day at around 250-275 by adding handfulls of chips every 1/2 hr our so.

I know others have had better results, but I'm happy with mine (4" vermicrete hearth insulation, 2"-4"(top of dome) of 8lb ceramic blanket topped with 2 inches of perlcrete. Still need a good insulated door. the one I made with 2 1/2" of loose perlite inside, really does not retain anymore heat that my 1/4" boilerplate door and I have no idea why.

RT

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Okay,
Here are some pics of my 'doors'

I made an 'interior' door for the first reveal to keep the heat in, hopefully. I just made a wood door and faced it with galvanized that I had laying around.

The 'outer' door is mostly to keep the oven closed off from any number of countryfied vermin that might like a cozy oven nest.

I have used it to just prop into place and keep a strong wind out of the fledgling fires...

Without further ado... I give you... the doors!

[dougrappe]

Re: Keystone CRA|CK Ugh!!!!

Nice doors Lars, which reminds me; I need to get to work on an outer door for nasty weather and especially that lower door for the storage area, I just spent the last year ratproofing the yard, don't want to invite them back just yet.

Regarding that one location shot in with the door photos, where exactly is your oven? Looks like some kind of Greek temple ruin (and that's a good thing as far as I'm concerned.)

Doug

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Doug,
I am building this oven on an area we call the 'flat spot'. It was the first level area on some acres outside of town. The sun can be brutal in the summertime, and I like to design and cast concrete architectural elements, so I decided to, kind of, formalize the area. Eventually I want to anchor a simple 'sail like' shade system to those columns.

The columns are pretty cool looking, and I oriented them in an exact circle--lined up with the 'cosmos', as it were. At first, I thought it may be a bit much, but I am really glad I did that because it makes it easy to find the north star, see at what point the sun is setting, use shadows cast to tell time, etc.

I have been noticing a ton of mice. It seems wherever you build a shelter, there will be some form of wildlife to try to take advantage of it.

Yesterday I was shoveling out some old coals from our firepit. (I don't know about the rest of you, but after pizza, I usually transfer the fire from the oven to a firepit with a shovel) ... and I was surprised by a family of black snakes living in the coals!

L.

[cynon767]

Re: Keystone CRA|CK Ugh!!!!

Lars- I had read somewhere here on the forum that the zinc in galvanized steel had a tendency to melt and release toxic vapors at wfo temps; I seem to recall from my welding days that zinc does in fact have a low melting point, which is why brass (copper/zinc alloy) is used for brazing- lower melting point than steel.

I would be very hesitant to use the glavanized sheeting on the inside of the door. Zinc poisoning is reportedly fairly nasty- not necessarily fatal, but very unpleasant:

"Metal fume fever"

another effect of zinc is to lose one's sense of taste and smell, a fate too horrible to consider after putting all this work into creating an oven to make the world's most delicious pizzas!

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Hi Jamie,

Thanks for the warning about metal poisoning. The inner door will not be used during high heat, and I have been having trouble getting my oven up past 700 degrees overall, so I doubt I will ever get to the point of vaporizing the galvanization on the sheet metal.

But, to be safe, eventually, I will construct a stainless steel door, and in the meantime only use this one to try retaining heat just to see how well it will stay hot. Perhaps starting at around 600 degrees.

I learned my lesson about disregarding the power of metal molecules with my sourdough starter this past month. Surely it was a 'wives tale', I thought. ( "Don't use a metal spoon, it will KILL it") Well, after using a stainless fork, and I am guessing here, the acid produced by the bacteria in the starter ( lactic acid) must have bumped some metal atoms off the fork, which go on a yeast killing spree.

The things these ovens cause us to learn about!

Lars.

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Okay then.
A few days ago, I thought I would see if a piece of 'bluestone' sill I had might work for a mantle/hearth. It did look pretty nice in there, but it was only 2" thick and just didn't have much heft. I decided a 5" thick limestone piece might be alot more fitting.

Cut it from a larger slab ( okay, for this I DID use a skil saw--diamond blade) then cut the letters in there ( by hand... chisels) and set it in place!

The fire burned 'white' all the way down to the sides. That part worked good, the pizza making was a disaster! I really wanted to have a smooth night, my in-laws already think I am a little nuts! But instead, I had one bomb after another. To make matters worse, I really had no cornmeal, flour, pam spray, or anything to make my peel less of of sticky disaster! AGGHHH. Out of 5 pizzas, maybe 2 were not sticking to my peel and making a complete mess.

Anyhow, here are some pics of the mantle.

Someday I will get this down.

Lars

Ps. Sourdough crust. Does add an interesting flavor, but... stuck just as annoyingly as the others.

[Rodneyf]

Re: Keystone CRA|CK Ugh!!!!

Lars, Lars, Lars, we have to stop this sticking for you before we all go mad. Have you tried making your pizzas on parchment paper and sliding them of the peel onto the oven floor for a few seconds before lifting them with the peel and sliding them off the paper onto the floor. It sounds to me as if you don't have enough heat in your floor, I cook at between 500F and 550F but I use a fairly dry dough mix that works well for me, but if your dough has more moisture it may require a higher temp than that.

[Lars]

Re: Keystone CRA|CK Ugh!!!!

Rodney,
Thanks for your ideas. The moisture content in the crust is one problem, though, last night I had MUCH heat in the floor. They would have been GREAT, but the transfer is difficult because the oven is a ways out from the house ( 25 min. drive), so I have to make up the pizzas pretty long in advance.

It has worked well in the past to keep them in the pan (aluminum cookie sheet with sides) until they heat up enough to come loose from the surface, then onto the peel, and (keep it shooshing back and forth) then onto the oven floor. I just got a sticky disaster first time out last night, which kept on compounding...

What is "parchment paper"? It reminds me of when we rented a car in London, an "estate car"...which turned out to be what we call a "station wagon".

I REALLY should have used a ton of flour or cornmeal on the peel.

[mfiore]

Re: Keystone CRA|CK Ugh!!!!

then cut the letters in there ( by hand... chisels)
Lars

.

Lars,

You continue to amaze me. Your oven is incredible. I love the hand chiseled limestone. You have tremendous skill.

The pizzas will come. Keep it up.