No announcement yet.

Oven on wheels

  • Filter
  • Time
  • Show
Clear All
new posts

  • Oven on wheels

    Well, I've made a start, sort of.
    I've studied hard, read lots of posts, and checked out lots of commercially available ovens. In an ideal world, I'd probably grab a FB Primavera 70 (28") and be happy, but the FB Oz website doesn't list them and I doubt I'd be able to justify the outlay if they did sell them here.
    Still, I like the look of the primavera ovens. I've given it lots of thought. I realised that pizza is the main concern, bread and roasts almost nil priority.
    So the general plan is this: steel framed stand, on heavy duty castors. Aiming for an oven 700-800mm internal, so the stand will be 1200mm across, giving about 200mm/8' either side for dome wall and insulation.
    Vermiculite insulating layer.
    Clay paver floor.
    Fire bricks are a horrendous price, ones at work seem mostly the insulating type, house bricks with no holes in them seem rare as bunyips, so adobe dome, as per Better Homes plans. 1 part fat sand, 1 part terracotta clay (fire clay unprocurable in South Oz except for one mob in Adelaide who quoted $115 + freight for a 15 kg/33lb bag) 1 part crusher dust, mix it then add 5% cement (optional). May substitute lime for cement.
    Vermiculite insulation over the dome, followed by render. As mentioned, I'm in country South Oz. Therefore, there is another resource available that no-one seems to mention on the forum. I've been thinking, next time I drive past a farmer renewing his fences, I shall jump out of my ute and beg some used barb wire from the old fence. I believe old barb wire will make an ideal shapable reinforcing for a dome. There may even be a part roll in my mums shed.
    $57 worth of steel tubing duly sourced from bro-in-law.
    Just scored enough white brickies sand to fill two 55 litre garbage bins. Free, from a guy who trucked it 150 miles so he could have white mortar between the bricks of his new house. Cost him an extra $800 over using the local yellow stuff. Beautiful sand, never quite understood the expression fat sand, til I saw this stuff.
    In proper Oz outback style, the frame will be tek screwed together, and the supporting sheet under the vermicrete will be corrugated roofing iron left over from my new chook house.
    Due to the size of tubing available, vermicrete layer will be 76mm/3". Not perfect, but it won't have to stay hot for days.
    Pavers - leftovers, $25 per square meter from local contractor. Haven't bought them yet. They are 2 inches thick, and they seem heavier than any of the firebricks at work, so, if you want to do mostly pizzas and not radiate heat for days, they should be enough thermal mass.
    Crusher dust is cheap as, as little as $18 for a bobcat bucket (half a cubic yard) I believe I may achieve a workable oven for around $3-400.
    They tell me adobe isn't waterproof hence the frame on wheels. Perhaps a decent addition of lime might help. I did wonder if the FB homebrew mortar recipe would work with terracotta, instead of fire clay.
    Anyway, the job is on. Can only work at nights, due to painting house on weekends as per instructions from She Who Must Be Obeyed.

  • #2
    Re: Oven on wheels

    Haven't done much yet, due to being a bit crook. Still can't find a supply of fireclay which is actually affordable. Found a mob in Sydney who can send it via Australia Post for $50/bag postage, which makes it only $65 /bag. I envy some guys on the forum here who can walk into a hardware shop and buy it for $15/bag.
    I'd still like to do the dome from the FB homebrew mortar rather than adobe. Anyone know of a hardware shop in Western Victoria that might stock Blue Circle or Cement Australia Brickies Clay? Got a mate going on holiday soon, who says he wouldn't mind picking it up on the way home.


    • #3
      Re: Oven on wheels

      Progress report. 2 by 100L bags of vermiculite ordered on evil-bay (about 7 cu ft) $89 including delivery to my door. Castors turned up. 4 x 5 inch castors rated at 100kg/220 lbs each. $50 including postage. May follow the example of another builder on the forum and add a couple extra to spread the weight, but I'm intending to keep track of the weight and keep it under 400kg/880 lbs. Smallish oven, pizza mass only.
      Just went down to the local contractors yard to buy the left over pavers. "Sorry mate, bloke came in and bought all of our odds and sods. We are closing down and the guy made us an offer for the lot." Bugger. Then I spotted the left-over pallet of high end stuff. "Yeah that's the display stuff. You can have a square metre of that for $25." Could not load them (42 bricks) into the ute quick enough. Why? Well they are made by a certain company that shall remain nameless but markets an almost identical product as fire brick. No bevelled edges as most pavers have. We'll see how they shape up.


      • #4
        Re: Oven on wheels

        I have a bit over 2 bags of fire clay available if you want some.
        Email me when you come down to Adelaide.
        Your vermiculite is also available from Thermal Ceramics at Beverley if you want some.


        Prevention is better than cure, - do it right the first time!

        The more I learn, the more I realise how little I know

        Neillís Pompeiii #1
        Neillís kitchen underway


        • #5
          Re: Oven on wheels

          "the frame will be tek screwed together" I hope you didn't mean the stand, I don't think tek screws are strong enough.
          Lime will not make it waterproof, in fact it will make it more porous I think. If your oven is on castors it may be better to wheel it out of the weather
          when not in use. Being porous is an advantage in that moisture is easier to get out.
          Barbed wire is great idea and is the standard reinforcing for mud brick construction.
          Good luck, sounds like you're on a mission with a vision.
          Kindled with zeal and fired with passion.


          • #6
            Re: Oven on wheels

            Pavers weigh 6 pounds for a 9"x4.5"x2" brick. Good density I think.
            I was bemoaning availabilty of clay when I was loading bricks. The guy said, you know that big hole out the back is a clay pit? This used to be the brick kilns. Bloody hell I said. I might jump the fence with a shovel and a bag. Might as well, he said, the bank gets it next week. Another victim of a shrinking housing market, rising interest rates and consumer belt tightening. We are hostage to outrageous fortune. Doesn't matter how clever you box, there's always something to clean you up and put you back in your corner. I wished them "all the best".
            Neil thanks for the offer on the fire clay-may just take you up on that..
            DavidS, the point of the wheels is indeed to wheel it out of the weather when not in use. As for Teks, well I have indeed bought the big monster ones they use for assembling steel frame houses, but have just about persuaded myself that when I get it all assembled and square I might just wheel it down to the high school for my 16 year old to MIG it all together in tech class.


            • #7
              Re: Oven on wheels

              Definitely weld it and make sure you have some diagonals.
              Kindled with zeal and fired with passion.


              • #8
                Re: Oven on wheels

                make sure you have some diagonals.
                Of course. That is one thing that has puzzled me on lots of steel stand builds I have seen here. To me, no diagonals = no strength. People leave the diagonals out, and use massive cross-sections with massive wall thickness. I don't want my build to end up so heavy. Hope this message looks alright when I post it. Chainsaw the cat just walked over the keyboard. I'd shoot him, but I'm afraid he'll take the rifle away from me and belt me with it.
                Have you seen the stand soild with the primavera 60? Not massive, considering how much the oven weighs.


                • #9
                  Re: Oven on wheels

                  P.S. I have 500 Litre tank, which is full, since its winter time. Being 500L, it weighs a minimum of half a ton. It has been standing on a frame made with tek screws for 10 years. Still might weld my pizza oven stand, though.


                  • #10
                    Re: Oven on wheels

                    Vermiculite turned up today. 3 days from ordering to my door. Very coarse, which I think is a good thing.
                    Consulted a bloke today who used to build steel framed houses in the Pitjantjatjara lands, then spent time welding at an engineering firm. He advised me to use the TEKS!!!
                    All the houses were put together with TEK screws and he said the material would tear before the TEKs pulled out or broke. Had an interesting discussion on how the cross bracing should be done. He said look at it this way - if you and I can sit on this frame, then its supporting about 450 pounds. (I weigh 230 pounds. He's taller than me, but I'm fatter) And I'm certain we would be able to sit on it. How much will the oven weigh? Well I intend it to be smallish and lightish, around 30 inches, 2 inch floors, 2 inch poured homebrew refractory or stabilised adobe, steel flue, 3 to 4 inches of vermicrete, etc. So, relatively light. And, still thinking. I deliberately chose fairly thin wall steel tube, because I want to roll this thing away.
                    He was adamant that getting welds on thin stuff that both looked good and had good strength was a challenge. Neither of us owns a mig welder, only ordinary arc. Quite a bit of info around for building for high wind conditions, hard to knock screws really.
                    Decisions, decisions. I'm mostly frustrated by the availability of things. Freight charges kill everything, so its been a compromise from day 1.


                    • #11
                      Re: Oven on wheels

                      The first steel stand I built for my oven was made with welded thin wall rolled hollow section 38 mm square. Thought it would be plenty, but there was too much flex in the stand and the oven weight was only 250 Kg I'm sure way lighter than what you are proposing. MY oven is only 21" int. Diam. The oven was screwed to the floor and does not move around on wheels.I now do a steel stand using 4mm thick 50 mm galv. Angle welded and there is absolutely no movement. Just make sure it's stronger than you would thinknit needs to be.
                      Kindled with zeal and fired with passion.


                      • #12
                        Re: Oven on wheels

                        "Anyone know of a hardware shop in Western Victoria that might stock Blue Circle or Cement Australia Brickies Clay? Got a mate going on holiday soon, who says he wouldn't mind picking it up on the way home."[/QUOTE]

                        Be careful of using bricklayers clay, sometimes also labelled as fire clay. This stuff in Australia is not fireclay. I have contacted Cement Australia who say that it is not refractory and is only designed as an addition to mortar in small quantities. On complaining that it is mislabeled they said sorry, but are unlikely to change it with only one complaint. The stuff may be suitable, but as they were unable to tell me what it contained I've decided to avoid it and use, the more expensive real fire clay from refractory suppliers.
                        Kindled with zeal and fired with passion.


                        • #13
                          Re: Oven on wheels

                          Mine is 50mm square tube. Not 4mm though. Man that's heavy duty. Intention is full width cross bracing. I am not worried about the steel actually supporting the weight. I AM worried about flex. Where can I find a pic of your stand? I don't seem to do to well with the search function.


                          • #14
                            Re: Oven on wheels

                            PS on the fireclay - I'm thinking its all about the proportions of alumina and silica? I can get that assayed. Cement Australias material data sheet DOES look a bit generic doesn't it? We write MSDS like that too. If you get too specific about the contents, then you are in all sorts of strife an individual batch falls outside the ranges you quote for each ingredient.


                            • #15
                              Re: Oven on wheels

                              Hi hows progress?

                              Just checking things out with your build and I noticed an older post has just poped up intitled 'Cast oven on a shoestring'. Basically a cast oven of Forno style homebrew mortar on a steel frame formwork which has now seen service for two years. Only problem is of course it uses the dreaded Fireclay in the mix...seems like your going to crush up a few house bricks yourself.. how.. the only thing I have come across is to use the slurry left in the brickcutter?

                              Regards Dave
                              Last edited by cobblerdave; 09-25-2011, 04:56 AM.
                              Measure twice
                              Cut once
                              Fit in position with largest hammer

                              My Build
                              My Door