Announcement

Collapse
No announcement yet.

Cast Refractory Pizza Oven Build

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

  • #31
    Re: Cast Refractory Pizza Oven Build

    I guess I'm just worrieng too much, the aggregate is from dense fire bricks, and maybe is not as weak as I imagine just dont have the experience and I only get one shot at this so really don't want to get it wrong..

    There is no other way than to keep adding water untill it becomes workable so I'm going to just go for it and hope for the best

    Thanks for your reassurance though..

    Comment


    • #32
      Re: Cast Refractory Pizza Oven Build

      Below are some pics for the basalt mine..

      Comment


      • #33
        Re: Cast Refractory Pizza Oven Build

        I don't know if you can notice the difference, but been "correcting" and refining the cutting of the bricks. This is the best I can do as I am using a hand held saw that is not easy to cut right on the marked lines..

        Also, I took some bricks to a shop that has a huge cutting knife for the entry bit. I needed that to be as good as possible. So now I think its ready for the next step

        The other pic is a cut section of a concrete sample with the basalt and crushed fire brick in it.. Hopefully it will be strong enough when its 7cm wide..

        Comment


        • #34
          Re: Cast Refractory Pizza Oven Build

          By the way, the entry form should be ready by the end of the week, and I'm planning on using galvanized steel sheets for the wall form. If all goes well I should be pouring my oven this weekend Would any of you recommend using reinforcing steel in the concrete or would that be a bad idea?? Maybe, reinforcing stainles steel bars or mesh??

          I have heard pros and cons on this site about this issue, but dont know if just using my concrete mix would be sufficient. I have tried to look for the staineless steel needles but it's not available here..

          Any thoughts or recommendations? has anyone had a bad experience on just using concrete without reinforcing??

          Appreciate the advice!

          Comment


          • #35
            Re: Cast Refractory Pizza Oven Build

            If you can get the stainless needles, use them, though I reckon you have to be careful you don't have any sticking out of the surface anywhere. I don't personally like the sound of using mesh or bars.
            But I have never tried it so my opinion isn't worth much.
            I would say though, if you would sleep better knowing its reinforced, do it.
            But if you do, make sure the mesh/bar is place very carefully in the mould.
            In particular, if I was doing it, I would make very sure that the mesh is not too close to the inner surface (the hot face) of the dome.
            The expansion coefficients are not very different, i.e the mesh and the refractory will both expand by the about same amount when they get to the same temperature, but the rate of expansion might be different, so put the mesh deep in the castable, so that the castable is trying to stretch the mesh when it expands, rather than the mesh trying to stretch the castable.

            Comment


            • #36
              Re: Cast Refractory Pizza Oven Build

              Thanks for the advice Journeyman!

              If I do end up adding the mesh I will keep that in mind, but still need to figure out what type of thickness the mesh should be to actually make a difference. I went to a firplace shop today to buy the vents and saw what type of mesh they use. Although its nothing like chicken wire, it looked pretty light and thin, and not that heavy-duty..

              gotta make a decision soon, we'll see what happens..

              Comment


              • #37
                Re: Cast Refractory Pizza Oven Build

                Its a tough decision. In concrete, reinforcing is there to provide tensile strength. It stops big beams and slabs bending and cracking by refusing to stretch on the outside of the curve. It does very little for compressive strength.
                In the context of stopping castable from cracking due to expansion and contraction duiring the heating/cooling cycle, it might be counter productive. I'd be very much guided by what the experts say - for example I guiess the fireplace shop has to guarantee their product so they'd be using what ever works I suppose.
                Thin might be better.
                For example, imagine if your reo wants to expand by 2%.
                If you have a wire of 1mm thickness expanding by 2% on heating, then your wire is going to try to be 1.02 mm thick.
                A 10mm wire is going to try to be 10.2 mm thick. So the pressure exerted on your castable is going to be a lot more.

                Comment


                • #38
                  Re: Cast Refractory Pizza Oven Build

                  Thanks for your advice Journeyman! I do get your point which is why I'm so reluctant :s

                  On a good note, I got my entry forms and the galvenized sheets for the walls.. Wohooo

                  Also, got 3 sacks of fondu which should be enough and lots of crushed firebrick. Things are finally moving

                  As soon as I got back from work today started working on my oven. I wrapped the first side of the steel around the coocking floor and put the entry form in place. Been applying lots of silicon to seal any small gaps..

                  Didn't manage to place the second bit of steel for the outer wall but prefer to do things slowly and make sure I've done everything right.

                  I hope by Saturday I can pour the entry and the walls, but we'll see what happens..

                  Comment


                  • #39
                    Re: Cast Refractory Pizza Oven Build

                    Make sure you use a release agent on the mould before you start making your casting. I use 50/50 motor oil, kerosene.
                    Kindled with zeal and fired with passion.

                    Comment


                    • #40
                      Re: Cast Refractory Pizza Oven Build

                      I sure will do that David. Just hope I didn't glue the entry forms too much that I will be able to remove them without breaking them..

                      Got everything done today in regards to the forms, so should be able to pour the walls tomorrow

                      The only remaining thing to do is place some deviders so that the walls are not one piece. Planning on putting three deviders, two beside the entry and one in the back (oposite the entry).

                      Comment


                      • #41
                        Re: Cast Refractory Pizza Oven Build

                        Guys do you think a 15cm or 6" flue pipe be sufficient for the oven?? and how long, 2m??

                        Comment


                        • #42
                          Re: Cast Refractory Pizza Oven Build

                          Yes a 6" internal diam flue would suit your 1m diam oven well. If it were mine I'd be making the flue height ( from the top of the oven door) approx. 1.5m.
                          Kindled with zeal and fired with passion.

                          Comment


                          • #43
                            Re: Cast Refractory Pizza Oven Build

                            Is there any reason why just 1.5m?

                            Comment


                            • #44
                              Re: Cast Refractory Pizza Oven Build

                              Originally posted by abulsamman View Post
                              Is there any reason why just 1.5m?
                              No, I just feel 1m is not enough to provide a powerful enough draw. The rest is really aesthetics. Basically the taller you go the bigger the draw you get.If it's really tall then you also need a bracket to secure the flue near the top. If it's 1.5m you won't need one, the flue height will look right in proportion with your oven and it should work well.
                              Kindled with zeal and fired with passion.

                              Comment


                              • #45
                                Re: Cast Refractory Pizza Oven Build

                                Ok, so it's trying to balance between amount of draw, while not having to place supports.. Thanks for the tip..

                                Comment

                                Working...
                                X