ThermoJax's 42 oven

[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.

[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

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

[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'.

[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.

[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

[ThermoJax]

getting closer

getting ready to close this puppy up.

[ThermoJax]

Re: ThermoJax's 42 oven

almost closed.

[ThermoJax]

Re: ThermoJax's 42 oven

I will close the oven very soon

[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]

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

chimney is now built. I screwed up and instead of working down from where I needed to go thru the roof with the simpson duratech 8 inch, I just kind of gutted it out, the result is that I just laid the side of the vent landing out about three inches shy of where it needs to be. So, now, as you can see from pic #2, the top of the chimney is 3 inches forward of the top outside of the outer arch.

[ThermoJax]

insulation is applied

I guess it is ok that the chimney leans forward, as the insulation is so thick that only a box could contain it, instead of an igloo. It must be 8 inches at the top and with my hand during a 350 degree fire I could feel no heat. My buddy has some left over house type insulation that he is bringing over now, and we will lay that on top of this inswool. I might even cover up the chimney stack, but certainly add to the dome, even if none is needed. They say you can't have too much insulation. ( I wish I had more below the oven floor, as the pad is pretty warm underneath. I used 2 inches of insblock 19, but wish now that it was 4 inches)

[ThermoJax]

yes, it is pretty tight in there

no much room from the sides of the oven to the plywood (osb) sides of my box like structure around the oven. I know it is a no no, having heat next to combustibles, but here we are anyway. I felt no heat during a 350 fire, so with the addition, soon, of extra insulation, I will close up my box.

[ThermoJax]

view from the front

this shows the plywood surround. I anticipate stucco on top of the plywood, or maybe stone veneer. Got to price that out.