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ThermoJax's 42 oven

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  • #16
    Re: ThermoJax's 42 oven

    Tom,

    How's it going and how are you doing?


    Chris

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    • #17
      Re: ThermoJax's 42 oven

      having just glued in course 2, I am disgusted with my handicraft. Too traumatized by the lumps and bumps that my cutting and gluing, mostly gluing, with the associated gaps from too much mortar, just to make sure it is strong that I don't want to even post pictures right now. I had notions of perfect brick cuts, needing hardly any mortar, I am so disappointed with my build so far. I so wanted to take some time off from work and finish right away, including curing, but according to what I have read, a long slow cure that brings up temps to near boiling to get rid of water, takes some time, perhaps weeks. I have yet to cut course 3, but the arch is in place. I stand firm with the make the arch on the plywood form method. Judging the brick placement, once cut into the arch, including the not yet placed mortar is somewhat voodoo science, but I bet I could do it better if I tore it down and shaved the bricks with the super duper harbor freight multi-purpose tool that shaves excess mud off the brick face. Having taken some glued bricks apart after 24 hours, I am amazed at how easy it is to clean off the mud, with or without the tool. The stuff must need more time to really get tough.

      I am having so much trouble thinking about the compound cuts needed for all remaining courses that the only one that I think that I can reasonably do is this one http://www.fornobravo.com/forum/28/m...me-2985-9.html ( the string method) Do a course,lay an uncut 1/2 brick up there, pop the string, which would account for both the angle and the bevel, mark the brick from the string. Then set a temporary jig just from left over thin slices of brick the wedged under the uncut 1/2 that they accomplish the bevel while the easy cut as marked by the string indicates the angle. Cut a bunch of right side cuts and then re-jig for the right side cuts. Would anyone be willing to look at this string method proposed by MRCHIPSTER is viable. I have looked at the chart proposed by JCG31 but cannot make heads or tails of it.

      Also, would you say that even if I put in my keystone plug by weekend, that I could not fire for quite a while. Perhaps my dream shall if not be denied, it might be delayed in order to cure properly.


      Your thoughts are appreciated.


      Tom

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      • #18
        Re: ThermoJax's 42 oven

        Don't hurry something that can last for decades.

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        • #19
          Re: ThermoJax's 42 oven

          Tom, I figured out a tool to help "me" with the compound cuts of the different courses and posted pictures and an explaination of the thingy.

          http://www.fornobravo.com/forum/f28/...ool-12478.html

          I don't know that you'll want to build one or a variation of one but it might help you.


          Regarding the frustration, It's normal. Very few of us here can imagine that our baby isn't going to be nearly perfect and that it's going to take so much time, that it's going to crack and all of the rest of it. The bricklaying skills are skills that almost nobody here has going into the build and then add in all of the rest of it. It's a lot of new things.

          You'll do fine, bit by bit you'll finish and the pizza will open a whole new set of skills to be frustrated by, but the pizza will be great!

          Chris

          PS. Remember that there is no perfect oven, and my point of view is just one of many here on the FB forum.

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          • #20
            Re: ThermoJax's 42 oven

            I am up to 5 courses, laid freehand, even though "the tool" is right in the center. I didn't use it at first as my soldier course ended up being like 43 instead of 42. My soldiers we cut at 20 degrees, then I cut the cheeks on a half brick and just lined the edge of the brick with the edge of the soldier below it and before I knew it, I was up to 5 courses. Now I have purchased a angle finder from HF and I find that my angle remains 20 degrees. I fear that the roof/dome might close in eventually, but it might be 6 ft tall. I saw a nifty chart from jcg31 for his dome, which says course 6 should have a 34 degree slope, so I cut a half brick with the cheek cuts and some off the bottom at an angle, and when I lay that up dry I have the 34 degrees, but the next course after that wants even more. I could do that 3rd cut from now on, but I suspect the indespensable tool sets them at the required slope,so why bother. The tool is 21 in but in order to use the tool, course 6 would be an inch inward. Visually unappealing. see the second picture. This is my proposed step in. But besides being ugly, is there anything structurally wrong with an uneven inner surface? Those first 5 courses have roughly the same amount of mortar from inner surface to outer surface, so the bond is strong I think. I also think that if I had used the tool, then the mortar would have been thicker on the outer surface and thinner on the inner (like a v that starts the intersection of the two bricks, inner surface of oven, and gets wider as it goes outward) Be nice to have a 19 dome, but that won't happen unless I make it look ugly. Any suggestions. I think I will just cut a bunch of cheeks for now till I hear from somebody.
            Last edited by ThermoJax; 09-24-2010, 02:22 PM. Reason: adding a picture

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            • #21
              Re: ThermoJax's 42 oven

              I have cut a notch in the bottom of row 6 to start moving the ceiling downward. Everyone seems to have a 21 radius and a 19 ceiling, so even if I get an inch drop, it will be better than no drop in height. I wonder that since my tool is fixed in the center and would normally produce a hemisphere, instead of something like drseward's oven, since he used an offset tool that accounted for the lowering of the roof, could I just using the fixed center point, lower the tool for every course, to achieve the 2 inch drop?

              Comment


              • #22
                Re: ThermoJax's 42 oven

                Originally posted by ThermoJax View Post
                ...could I just use the fixed center point, lower the tool for every course, to achieve the 2 inch drop?
                Yes, that is one method used here so you'll end up with your desired dome height.

                I were you I would remove a couple or three (or four) courses and start over. You should be able to easily pry each brick loose with a screwdriver or something.
                Last edited by fxpose; 09-24-2010, 06:01 PM.
                George

                My 34" WFO build

                Weber 22-OTG / Ugly Drum Smoker / 34" WFO

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                • #23
                  Re: ThermoJax's 42 oven

                  Take it down and start over? I am really, really tempted. My new harbor freight multipurpose tool can really shave that expensive mortar, but I am on my third tub of pre-made fire mortar, which I am assured by a third party who I definetly the Man when it comes to hot things like boilers and kilns here in Jacksonville, better than homemade refmix. There are areas on the lower course that just kill me to look at them. On the other hand, I can just ignore the obvious and finish the dome tommorow...

                  hard to decide. My wife says this build is not going quickly or well. Mostly me standing around thinking.


                  Tom

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                  • #24
                    Re: ThermoJax's 42 oven

                    You'll have such steep angles there I don't know how structurally sound your dome will end up being, with a near flat dome top. I wouldn't do it.
                    George

                    My 34" WFO build

                    Weber 22-OTG / Ugly Drum Smoker / 34" WFO

                    Comment


                    • #25
                      Re: ThermoJax's 42 oven

                      Well, the five courses so far seem strong, especially since they are almost brick on brick, the mortar being fairly even from inside to outside. I suppose that if I had used the tool earlier, that each course would have thicker outsides, flush insides. But I think that this course 6 with the notch cut out of the bottom will spread the force from courses 6-14 in the downward fashion that 1-5 require. Maybe i can continue shortening the tool, not have a super smooth roof, and get the heat down to a shorter level.

                      As always, everyone's advice is appreciated.


                      Tom

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                      • #26
                        Re: ThermoJax's 42 oven

                        I would not tear it out. A flattened dome is bueno, but you may have to cut a couple of wedge courses. Do not try and make it up all in one course, use several to get the height to where you want it.

                        Comment


                        • #27
                          Re: ThermoJax's 42 oven

                          Originally posted by ThermoJax View Post
                          ... But I think that this course 6 with the notch cut out of the bottom will spread the force from courses 6-14 in the downward fashion that 1-5 require.
                          Actually, subsequent courses above that will create more lateral force than a downward force.
                          I would at least wait for others to chime in on this matter.
                          George

                          My 34" WFO build

                          Weber 22-OTG / Ugly Drum Smoker / 34" WFO

                          Comment


                          • #28
                            Re: ThermoJax's 42 oven

                            Thank you. I do have to tell you that even my soldier course has some 1/4 inch gaps here and there, but it is the burning chamber, and so far, far away from the outer arch, that with judicious use of mortar here and there, perhaps ,I won't be my own worst critic over the years to come. My favorites are the second ovens for the builders. The second oven is apparently so much sweeter, as the builder has learned a thing or two about a thing or two.


                            Tom

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                            • #29
                              Re: ThermoJax's 42 oven

                              The reality of the forces involved is almost inconsequential for the mass and size. The thickness of the dome and the bond strength of the mortar allow a huge amount of leeway. This is the only reason that so many non-mason/structural engineers are able to build a dome structure. This is, in fact, the beauty of the FB design.

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                              • #30
                                Re: ThermoJax's 42 oven

                                The oven had numerous problems. Looking at the arch from the inside showed problems. The left side was doglegging left, not curving inward. Then, there was a number of joints lining up (apparently one of the causes of cracking later) and then there was the problem of the oven staying on a 20 degree slope. My soldier course was cut at a 20, and I cut a 5 degree angle on both cheeks, no bevel and no slope cut. So 6 courses up, it was still on the 20. I have doubts that the thing would ever close up.

                                So, I used my harbor freight multi purpose tool and took down a number of levels, as well as certain offending sections that had joints that lined up, and rebuilt. My contact here in Jacksonville who works on all things high heat tells me to use premixed mortar, so I have. It is expensive. Like in the ninety something dollar range for a tub. By Friday morning I had purchased my third tub (three trips) and was sure that this third tub would do me. Well, it is Sunday morning and after the rebuild, I have 7 courses complete (that includes the soldier course), and am out of mud. If I had mud, I am sure that I could finish the dome today. I guess I should just cut today, plus shave off grunge from the inside.

                                I would also like to sing the praises of that multi-purpose tool. It cut right thru the semi dried mortar. I think it would have kicked butt even on cured mud. I declared a "Dad Emergency" and drug my 11 yr old daughter and 14 yr old son out to help with the tear down. My daughter had to shave all the bricks that had mud on them. My son had to butter up the bricks and hand them to me. As you can imagine, they were thrilled. (not) I took the opportunity to put a slop cut on the last 3 courses and started using the "tool" as a guide, and now the oven seems to be back on track towards closing up. Obviously, this will not be a drseward oven. But, kay sara sara, what will be, will be.

                                Tom

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