Announcement

Collapse
No announcement yet.

Steel Dome Oven

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • Wiley
    replied
    Re: Steel Dome Oven

    Buckeyebreadman,
    Baking bread is no problem, I usually fire for a bit longer than I do pizza (my WFO is pizza ready in about 40 minutes from match) so something on the order of a full hour and although I haven't tried a second batch I would think that you would not have to fire much longer than that as there is plenty of retained heat at the end of baking one batch....although you would probably have to extend the length of the bake.

    Since the steel conducts heat more efficiently than brick the time needed to saturate the dome is shorter. I inquired of Mklingles (the member who was doing the heat analysis of his oven) about the relatively short heat up time and here's his reply:

    quote:

    You are correct that steel is a much better conductor of heat than fire brick. The conductivity of steel is ~43, and firebrick is ~1.4. So, about 30x better conductor of heat!.

    The steel is probably black. So, it is absorbing and re-radiating heat, not so much reflecting it. It would quickly heat through and radiate the heat into the brick and into the oven equally.

    I agree with your notion that the heat spreads through the steel very quickly then radiates into the brick much more evenly. My dome clears (burns off the soot) first on the top of the oven and takes a while longer to clear down the sides.

    Also that 30x greater conductivity means the steel absorbs heat from the hot gases from the fire 30x more efficiently then the brick. So you have less heat flowing up your chimney.

    Cheers!

    end quote.

    I have had great success heating for a single bake of rolls and then when I pull the fire I save it (keeping it going in a Weber BBQ). After the rolls are baked I allow the oven some time to cool and then I put the fire back in the WFO on one side and place a pork shoulder on the other side. I place two firebricks on their long edge between then fire and the pork shoulder. The bricks were in the WFO during the fireup and left during the baking of the rolls. They form a barrier between the coals and the pork. I then place soaked wood chips on the coals and smoke the shoulder with the door open a bit to allow some air for combustion. When the pork is smoked to my liking I remove what's left of the fire and close up the oven. The next day I have wonderful pulled pork on the rolls I baked.

    I will add that I have yet to build an insulated door, I'm still using the simple wooden one with the pie plate for a window I mentioned in this thread.

    You should have no problem baking bread in a steel dome WFO.

    Bests,
    Wiley

    Leave a comment:


  • buckeyebreadman
    replied
    Re: Steel Dome Oven

    Got my tank (40 incher), cut off the ends, found a split rim and am ready to get started!!

    I have a question though........does your oven maintain temps long enough for Bread Baking?....some of the traditional ovens stay hot enough for Many hours.......just curious..

    Leave a comment:


  • Wiley
    replied
    Re: Steel Dome Oven

    Bill,

    Thanks for the kind words.

    In retrospect the only thing I would change is to make the transition area larger (the area where the smoke leaves the oven and enters the chimney). Once hot and at temperature there is no problem but a larger transition and perhaps a larger chimney x-section (8 inch rather than the 6 inch I used) would eliminate any smoke out the front during fire up. Other than a small amount of smoke at fire up after two and a half years use I have no complaints with the WFO.

    Presently I, like many, are awaiting the arrival of Spring here in the Pacific Northwest. Temperatures this morning were near freezing...what's with this weather?

    With respect to my second WFO: I've managed to clear and level an area for my little FG trailer near the pond site, however, all the rain has made excavating the rest of the pond a non-starter to date. I did order and receive the EPDM liner. That's out of sequence...getting the liner before the hole is finished but the price of shipping is headed upwards. The liner came from Tennessee and the shipping alone was $935, and that was just over a month ago. Just checked and the cost to ship that same order today is $1340. Yikes!

    Bests,
    Wiley

    Leave a comment:


  • buckeyebreadman
    replied
    Re: Steel Dome Oven

    Wiley, I too plan on a campsite oven (moveable if necessary) and another at my home....
    AND I'm a midwest sailor!...I've really loved and been tremendously informed by this site and especially by your thread...can't thank you enough...
    anything to add in retrospect?
    Thanks again, Bill

    Leave a comment:


  • Nic The Landscaper
    replied
    Re: Steel Dome Oven

    In Portland go to Precision Counter Tops for Soapstone. You will get your best pricing on remnants and left over cut outs. Even at remnant prices a 60" oven would be expensive though. Go talk to My Fiance Molly at Precision she'll be happy to help you.

    Leave a comment:


  • Wiley
    replied
    Re: Steel Dome Oven

    Hi Kevin,
    First, you're more than welcome for any help I was in the design of your WFO. This forum is great for alternative ideas and mutual sharing of thoughts on our unusual creations.

    I'm not on Facebook so I couldn't view the photos of your finished WFO. Regarding the height of internal dome and height of door: It is my understanding that that ratio (63%) is an emperical one derived from study of lots of successful WFOs. It has do do with airflow and proponets state WFOs with that ratio allow for incoming air to most efficiently supply air to the fire and exhaust the products of combustion (gasses smoke etc). I usually try not to reinvent the wheel and so go with what works adding my own twist on what I'm doing. One does need to keep in mind that with such departures from the norm there is a risk of less than hoped for results.

    As I haven't seen your photos I do not know how difficult it would be to fabricate a temporary structure to lower the door height to see how that effects the performance of your WFO. As for too great an interior height that could be reduced by raising the floor (which would also lessen the door height and change the ratio). Of course that would change the working surface height as well as the heat up times (due to greater mass) as well as the weight of the finished WFO. Lots of factors to consider. But it wouldn't be much work to lay a temporary layer of bricks on top of the existing floor and so test the idea of lessened door and ceiling height. Five foot by five foot is a large WFO, you must have a source of inexpensive firewood.

    My next WFO will be a steel dome as well (yes, I plan on building another, perhaps next year at a campsite/trailer site I'm constructing next to a pond I'm digging right now at the other end of my little five acres). I hope to find a condemmed propane cylinder which has elliptical ends. This will make for a WFO with a lower ceiling. Not that I'm dissatisfied with my hemispherical WFO just the new WFO will be strickly for pizza and other low dishes. However, at the speed of my construction and demands upon my time it may be built the summer after that, but it is in the plans. I've attached two photos of bucking up some of the logs from the trees I've pulled over at the pond site (one gets the root ball out at the same time as one drops the tree if one pulls a tree over), and one of the same logs split.

    I don't know of any source for soapstone here in the PNW.

    Bests,
    Wiley

    Leave a comment:


  • firebug
    replied
    Re: Steel Dome Oven

    Wiley

    It's been a while, my project is done and you can see some pic's if you google kindle kart, It should bring up my facebook account and you can go through my photo's of my wood fire pizza cart in Portland.I think the oven is very well built I love the steel dome for transmitting heat on my oven floor,but I would do a couple things different,the main issue is my dome is 28 inches away from the floor although my floor gets hot enough I think it should be more like 20 inches.
    The oven is big 5ftx5ft inside measurement,also I think my oven opening is to big letting too much heat to escape out the door and up the chimney. Do you think 20 inches sounds correct for floor to top of dome ratio?I plan on taking all my fire bricks out pouring a 6-8 inches more of insulation concrete then putting firebricks back.I really don't care how firebricks cook my pizza so I might add a slab of soapstone on top of my firebricks,Any thoughts on this?Do you know a good place to buy soapstone in the northwest?


    Thanks for all your help....kevin

    Leave a comment:


  • pdhawan
    replied
    Re: Steel Dome Oven

    Wiley,

    I have been reading your thread from the beginning - what an excellent project and well documented from the beginning.

    Lots of great ideas.

    Thanks
    Provin

    Leave a comment:


  • Wiley
    replied
    Re: Steel Dome Oven

    Yes, by volume 1 part calcium aluminate cement to five parts 1/4 minus crushed basalt. Check post number 48 in this thread.
    Bests,
    Wiley

    Leave a comment:


  • firebug
    replied
    Re: Steel Dome Oven

    Wiley.

    You used 5 to 1 ratio for your cladding?

    thanks...kevin

    Leave a comment:


  • Wiley
    replied
    Re: Steel Dome Oven

    Kevin, I formed up as I went. I would bring to your attention the initial form which I made around the base of my WFO. This allowed me to get past the "vertical" (where the concrete is standing and supported upon itself ) and to be forming against the dome (cylinder). The further up the dome/cylinder the more the concrete is supported as opposed to the concrete standing on itself. Casting the ring around the base also allowed me to get a feel for how easily the material works and how soon it kicks off.

    When forming the triangles I created them by eye and placed aluminium foil between the joins. I pressed the foil into the just formed triangles before it fully set off. This mandated the expansion joint occur where I wanted it to occur rather than form (crack) at some perhaps less desireable location. The size of the triangles was determined by the size batches I made...again learned by casting the initial supporting base mentioned above.

    The stuff goes off quickly and one is advised to have a plan and have tools laid out etc. Not to panic you, but figure 20 minutes from mixing to unworkable, so not a problem with a reasonable size batch but no time to go looking for that trowel or aluminium foil. By the end I found I enjoyed working with the material, it easily and quickly assumed an initial set and allowed one to hold shapes with a trowel in one hand and shape with a trowel in the other; after a few moments the held material would stay in place (allowing it to be smoothed and faired into the rest) where with regular cement/concrete it would have slumped when released.

    I also found that I had good results by mixing a batch and then cleaning up the wheel barrow (where I mixed it) with a hose and brush. Then starting a new batch. By the time it was mixed and ready to go the previous batch was quite hard and I could form against it without damage. You should have no difficulty alternately working one side and then the other of your cylinder.

    Hope this helps, looking forward to some photos...
    Bests,
    Wiley

    Leave a comment:


  • firebug
    replied
    Re: Steel Dome Oven

    Wiley,

    I went back and looked at you pic's,and wanted to know if you formed up your cladding triangles? or did you form the triangles against the steel dome as you went. how long does it take to set up? I'm going to start on Friday and hope to be done on Sunday,Thursday (tomorrow) I'm going to build a fire and hope it vent's well. I used a 6 inch chimney from home depot.we will see thanks again...kevin

    Leave a comment:


  • firebug
    replied
    Re: Steel Dome Oven

    Wiley

    Makes sense,1/4 basically has the caricature of sand,and now that i think about it i think the basalt supplier said 1/4 inch minus that will save me a step thanks,I followed up on the lime, I guess you only want to use lime with normal cement the lime help's keeping the cement from burning out.so if I use fondu I won't need it....thanks again.

    Kevin

    Leave a comment:


  • Wiley
    replied
    Re: Steel Dome Oven

    Kevin, I'm not as sharp as I once was (was I ever?), however, something about your mix sent me searching for something I remember reading. Back in 2008 there was a thread about casting and a proper mix; David S. in Australia had this addition:


    Originally posted by david s View Post
    Lime and calcium aluminate together are not good. I've tried this and the lime acts as an accelerant to make your brew go off much faster. The calcium aluminate is also quite temperature dependant. On a cold day it takes ages to go off (use warm water) On a hot day it'll go off really fast (use chilled water or some ice) don't mix product that's been sitting in the sun. It's also quite thixotropic ie It'll start going hard but if you give it more mixing or vibration it liquifies again weird stuff.
    So you might want to keep that info in mind when you start mixing your brew. Calcium aluminate goes off pretty fast on it's own. Also I would see if your source for basalt has it in something smaller than 3/4 inch. My thinking is you would want something more like "xx minus". The minus in crushed rock terminology means it will have finer/smaller particles of the same material intermixed in the load. Having the fines of the same material would make for a final mix with more consistant characteristics throughout, as opposed to adding sand of unknown composition. My personal choice was 1/4 minus as a simple one step mix. I didn't have to add or measure out anything but the Fondu to the stuff. It's your WFO and so you will do as you see fit (as to be expected and hoped).
    Bests,
    Wiley

    Leave a comment:


  • Wiley
    replied
    Re: Steel Dome Oven

    Hi Kevin,
    Finally I have a working and hopefully safe, virus free computer system. I just got back online using this machine this evening and of course the first place to check...Forno Bravo!

    Regarding your question: If I am understanding correctly, you are asking whether you should place some kaowool between the steel and the basalt fondu concrete mix. I would say no. I would suggest you simply place a layer of aluminum foil between the two. The kaowool goes on after the cladding.

    The aluminum foil wil create a slip surface so the steel can expand and contract and whatever movement should be accommodated. I suggest that when you apply the concrete that you create some larger polygonals so that the pieces of heat sink can act as individual plates. We've discussed this before, the idea is sort of like a snake skin. The actual scales in a snake skin are rigid. The expansion needed as the snake respirates is accommodated between the individual scales. The plates are held to the steel liner by the steel spikes.

    Great to learn that your project is coming along...some pictures would be nice:-) That seems like a good price for Fondu, compared to traditional portland cements it is fairly expensive but IMHO, worth the cost.

    Hope this helps,
    Wiley

    Leave a comment:

Working...
X