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-   -   How long to get to temperature? (http://www.fornobravo.com/forum/f17/how-long-get-temperature-18713.html)

man7sell 12-12-2012 07:11 AM

How long to get to temperature?
 
1 Attachment(s)
Yesterday I fired up the pizza oven, probably on it's 10th cycle by now. It took some time to get the mass up to temperature, close to 3 hours. Even used a propane weed burner to help the fire along. The wood I'm using is cherry and I think that this is a good long burning wood but not so high in it's BTUs. Maybe I should start with a hotter burning wood and switch to cherry after.

How long does it take your oven to come to cooking temp?

deejayoh 12-12-2012 09:07 AM

Re: How long to get to temperature?
 
I cook with cherry wood and it takes maybe 90 minutes to get the oven up to temp. Sometimes less.

I don't always use cherry when starting the fire, usually I use fir or scrap lumber (SPF or cedar) and then throw the cherry on when I am getting ready to cook.

But I have always thought that cherry and other hardwoods are pretty high in BTU so should heat the oven pretty well?

Les 12-12-2012 09:21 AM

Re: How long to get to temperature?
 
I can get it to clear around 2 hours if I keep a decent fire going. I usually give it 3 hours and have a moderate fire. My oven is 42 inch.

man7sell 12-12-2012 09:23 AM

Re: How long to get to temperature?
 
Thanks for the replies. Maybe my cheery is not as dry as it could be. Mine is also the 42 inch so maybe 3 hours is what I can expect.

Wiley 12-12-2012 10:13 AM

Re: How long to get to temperature?
 
My 40 inch diameter WFO is steel domed and from match to first pizza takes between 40 and 45 minutes. I'm fairly certain the speed of heat up is due to the more rapid take up of the heat from the fire by the steel as well as quick conduction of the heat to the refractory. Using a draft door also helps with faster firing time. It's been four and one half years since first fire up and no problems so far.

Two nights ago I built a small fire with four pieces of madrone approximately three inch diameter and maybe a foot long with some kindling of alder. It was allowed to burn for one hour and then I moved what was left of the fire off to one side and moved two firebricks I had placed in the WFO before firing to form a barrier wall. With the coals on one side of the wall I slid in a pork shoulder in a S.S. roaster on the other side. Throwing some fresh green alder on the coals the pork shoulder was allowed to smoke for twenty minutes with lid off. I then raked out the coals, covered the shoulder (after pouring half a beer into the bottom of the roaster) and shut up the WFO. Yesterday morning: perfect pulled pork.

WFOs are great!

Wiley

man7sell 12-12-2012 10:34 AM

Re: How long to get to temperature?
 
Interesting Wiley, that a fast heatup for sure. Now a question, what's a draft door? like a door with a small opening?

Paul

Wiley 12-12-2012 12:24 PM

Re: How long to get to temperature?
 
Paul here's a link to a posting on my thread which has a photo of a prototype draft door.

http://www.fornobravo.com/forum/43/s...html#post41508

This was a prototype made in Hardibacker which didn't last long. I used the broken pieces as a pattern to cut one out of 1/8 inch (10 guage) steel plate. Hardibacker did not take the heat, it outgassed a malodorous smell and became brittle within a few firings. The new door had a curious characteristic in that it caused the WFO to "pant" much like a steam engine climbing a grade. The panting goes away after a few minutes with the intake becoming a constant rush of air into the WFO.
Here's a link to my WFO panting:

Panting Wood Fired Oven - YouTube

I could permanently remove the panting by increasing the size of the opening, as simply raising it about a half inch up from the entrance floor causes the panting to stop. I've left it as it is simply because I think it's cool...my oven is alive!

Draft doors are worth the trouble to build as they really increase the air flow causing the fire to catch and burn hot and fast. They do need to be made of metal as they do get very hot. I've measured a surface temp over 500F with a IF thermometer on mine.

Bests,
Wiley

man7sell 12-12-2012 01:21 PM

Re: How long to get to temperature?
 
Love the steam engine Wiley. So I have a plasma cutter and a hunk of steel plate that I was doing to use for the door. It's a disk so maybe I will have enough to build the smaller inner door for when you want to slow roast, and the outer door with the draft slot. Have to measure it up this weekend.

david s 12-12-2012 04:43 PM

Re: How long to get to temperature?
 
Quote:

Originally Posted by Wiley (Post 142796)
Paul here's a link to a posting on my thread which has a photo of a prototype draft door.

http://www.fornobravo.com/forum/43/s...html#post41508

This was a prototype made in Hardibacker which didn't last long. I used the broken pieces as a pattern to cut one out of 1/8 inch (10 guage) steel plate. Hardibacker did not take the heat, it outgassed a malodorous smell and became brittle within a few firings. The new door had a curious characteristic in that it caused the WFO to "pant" much like a steam engine climbing a grade. The panting goes away after a few minutes with the intake becoming a constant rush of air into the WFO.
Here's a link to my WFO panting:

Panting Wood Fired Oven - YouTube

I could permanently remove the panting by increasing the size of the opening, as simply raising it about a half inch up from the entrance floor causes the panting to stop. I've left it as it is simply because I think it's cool...my oven is alive!

Draft doors are worth the trouble to build as they really increase the air flow causing the fire to catch and burn hot and fast. They do need to be made of metal as they do get very hot. I've measured a surface temp over 500F with a IF thermometer on mine.

Bests,
Wiley

There is a downside to using a draft door in that it causes such a rapid rate of temp increase that you then risk damaging your refractory. It creates the same problem as using forced air induction which also shoots the temp up very quickly. Temp differential between the crown of the dome and the sides at the base will be considerable as refractory is not particularly thermally conductive (unless you have a steel dome). I think it is preferable to allow the thing to rise in temp slowly and safely. 400 C / Hr is way too fast and asking for trouble IMO. Most potters try not to exceed 100 C/hr.

Wiley 12-12-2012 09:03 PM

Re: How long to get to temperature?
 
Hey David S and Votavidone, I should probably post this under the Travel heading but thought that you were both following this thread I might take this off topic for a moment or two. Since you both live in Australia you might give better insight than most.

My wife and I are flying to Australia in late March and be in country thru early April. We are flying into Sydney and spending a day or so and then boarding the Indian Pacific to Perth and again spending a day of so and flying onto Darwin. There we will spend another day and board the Ghan to Adelaide. We will be traveling light and wondered what we should be expecting in regard to temperatures...don't want to take more clothes than needed. That late in the season should we be looking at shorts and tees or trousers and long sleeves? Sun screen or rain gear? Shoes or sandals? Any suggestions welcomed.

Thanks,
Wiley


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