ThermoJax's 42 oven

[ThermoJax]

vent landing starts

I had to flare and extend. the vent landing out to correct for too small of a inner arch (10.5 instead of 12.5) Since it is so wide, I kind of have a eyebrow shaped outer arch, as seen here

[ThermoJax]

Re: ThermoJax's 42 oven

Here, I finally close it up. Notice the teardrop shape that seems to have developed. Oh well, I guess my next oven will be better, plus that whole thing is going to be buried under insulation and an outer housing structure, and on top of that , any guests won't have any idea how sloppy this thing is.

Last night I shimmied into the oven and applied homebrew into some places that badly needed to be filled in. Now I have an electric skillet set at 200 in the oven and then normal house insulation plugging the hole. Perhaps a week of this curing before firing, or maybe increasing the temp on the skillet to 300 for a while.


Tom

[ThermoJax]

Re: ThermoJax's 42 oven

I will close the oven very soon

[ThermoJax]

Re: ThermoJax's 42 oven

almost closed.

[ThermoJax]

getting closer

getting ready to close this puppy up.

[SCChris]

Re: ThermoJax's 42 oven

Anyway you twist or turn you’re going to spend money on the chimney. I decided that the Duravent was what my best choice was. I wanted to put in one chimney and not have to replace it, if possible. I wanted the double wall insulated because it’s safe heat wise and earthquake wise. It’s stainless and guaranteed for many years of use and in the coastal area corrosion is a problem. It’s also what’s best understood in the building trade, real estate trade, if and when one of these needs people get’s involved.

I used 8” DV. I don’t know that if you push your chimney up 10 feet if you could go with 6” because of the better draw. You might save money here.

In the hardest, most extended burns, the exterior of my chimney is only warm. I can and have held my hand on the exterior surface during these burns and only needed to remove it because of the discomfort of holding my arm extended.

Dmun is right about the aesthetics of a SS chimney, they're not pretty and I'll likley hide mine.

I know that I would make sure that I get the chimney up for safety sake, whatever it costs.

Chris

[dmun]

Re: ThermoJax's 42 oven

I wouldn't use single wall stove pipe anywhere near your beautiful new wooden structure. Even if you had the presence of mind to replace it every couple of years, it still gets REALLY hot on the outside, and you have the problem of how to safely get it through the roof.

A masonry chimney is marginally less expensive, material wise, than the duravent, but you still have to build and support the surrounding masonry, and there is a lot more labor involved.

I built the largest masonry chimney that I know about on FB, but I mostly did it because I think stainless chimney systems are as ugly as homemade sin. That's just my personal taste: other people like them fine.

[Millstone Man]

Re: ThermoJax's 42 oven

I ran my chimney through the roof and used a double wall stainless. I think you could get by with a single wall and a couple of 30 degree bends. In order for it draw properly you need to be 2' above anything within 10'.

[ThermoJax]

Re: ThermoJax's 42 oven

It is time to plan the chimney. As you can see from this side view, my vent is under my roof. If I went straight up from the vent, I would have 5 feet before I hit the plywood bottom of the roof. Some have done a 3 foot straight chimney, but that would leave 2 ft to disperse the heat. Can I vent under my structure, or must I do something like 2 -15 degree turns and not shoot the heat under my structure. Also, I get the feeling that a clay flue liner is way cheaper than steel. But I wouldn't guess that you could put 2 bends in a clay liner, plus I would guess that clay is heavy and it might be tough to support. Can I go with something cheaper than the duratech stainless steel double wall system, which pizzabob says costs 863 for his. How about single wall?

Thanks for your advice


Tom

[SCChris]

Re: ThermoJax's 42 oven

Bravo on the attitude! You're going to find, once you finish and have a bit of time to cook and reflect, that you're putting great food out.

Best to you and your family!

Chris

[ThermoJax]

Re: ThermoJax's 42 oven

Have you ever heard the definition of an expert. it is someone who, in a narrow field of study has screwed up in almost every conceivable way. At this rate, I will soon be a WFO expert. But, it doesn't matter. I am having fun, and learning alot.

[ThermoJax]

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

[Tscarborough]

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.

[ThermoJax]

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

[fxpose]

Re: ThermoJax's 42 oven

... 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.