7 years in the waiting i get to start my 42" pompeii

[SteelandStone]

Re: 7 years in the waiting i get to start my 42" pompeii

I have to agree with NCman, Gulf and the others about the width of the vent area being the key factor. My vent area is only 8" deep inside but it is 20" wide and 12"tall and I get no smoke out the front. I can only tell you what my personal experience is with my oven as I have not seen anyone else's in person to compare it to.

[Gulf]

Re: 7 years in the waiting i get to start my 42" pompeii

My oven?s throat was also designed to help carry the weight of a firebrick lined chimney/flu around the double outside arches to the vcrete layer. In a recent discussion on another thread, Stonecutter commented that he thought that it was the reason that my oven drew real well. (My 44" oven has only, roughly, a square 8? X 7 ?? ID brick liner) That may be the case, but I really think that the "double outside arches" may also be the key to this.

A recent example (without the massive throat) is SteelandStone?s double outside arch design. The "double outside arch" makes the smoke jump up a full 4" before it can exit the outside (outside arch). I'm looking forward to see how his works out .

EDIT: Looks like the verdict was already in. Check this out!

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

Yes maybe he will shed a bit more light on it for me I really don't mind the work it's going take to rebuild it if it comes to it I can't really fire it up yet either to test as my temporary roof is plastic and the weather here at the min would not like my bare firebrick dome torrential

[NCMan]

Re: 7 years in the waiting i get to start my 42" pompeii

Well....if it is important to you that it draws real well and get little to no smoke out the front, then you may want to rebuild it while you can. Without an actual throat area, you are apt to get some smoke out the front, but every oven is different, in different conditions, so there is no real way of saying for sure. See if you can get Gulfs' take on it.

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

Yes I was looking through gulfs photos (again ) ha today plus others with a wide tapering vent which is what go me worried !

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

Thanks for your help Carl every opinion is a valid opinion! I suppose if doesn't work that well I could always go down the grinding route just to open out the bottom of the vent

[NCMan]

Re: 7 years in the waiting i get to start my 42" pompeii

But would you agree that the vent size is maybe on the small side being only 8x8

Yes. I believe the vent size is technically ok, but a wider throat area is what would help, leading to the vent. A tapered/shelfed throat area helps alot. It gives the smoke a place to collect prior to being drawn out the actual vent. Take a look at Gulfs' Build. It's a great example of this. There's lots of others, I'm sure.

[NCMan]

Re: 7 years in the waiting i get to start my 42" pompeii

Lee.....in my opinion, after getting the dimensions and looking at your photos, I think you'll be ok. It would be better, I think, if it was wider. Not that it is too small in area, it's just that a wider vent can sometimes draw better and some smoke can escape a vent that is too narrow, even a deep one. Just my opinion, though. I'm still building my first WFO, but, like you, I do alot of reading and research, seen quite a few ovens in action and have been using my WFO for awhile now. My opinions are based on that, as well as prior masonry experience. Hopefully, you'll get a few more. I wouldn't tear anything down until you get some knowledgeable and experienced folks also give you some advice. Just my 2?.

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

But would you agree that the vent size is maybe on the small side being only 8x8

[NCMan]

Re: 7 years in the waiting i get to start my 42" pompeii

Lee.....in my opinion, your tapering is fine. On an outside oven, it's good to have your opening increase, as opposed to decrease in size. I think that part of it is ok.

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

The outer arch with the vent is 600mm x 360mm 23.1/2 x 14.1/4

[NCMan]

Re: 7 years in the waiting i get to start my 42" pompeii

Page 10 has some photos of the vent opening NCMan. Looks like it is deeper than wide, with the opening 3 bricks wide. Maybe you can grind the bottom of the brick to each side and make those a bit more funnel shaped? An opening 5 bricks wide along the bottom would give you another couple inches on the opening width on each side. I think it would help catch much more smoke exiting the oven towards the outsides of the arch. Chimney height will also make a difference. Plus you are outside so a little smoke out the front isn't the end of the world

I saw the photos. I asked for dimensions on both the oven opening and the vent.

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

Yes tony I did think about grinding the inside but it would proberly look ugly and proberly take longer than maybe just cutting out maybe 4 course on each side and start again

[leetheldc]

Re: 7 years in the waiting i get to start my 42" pompeii

I've just had a measure and the inside arch is 500mm 19.3\4 x310mm 12.1/4 and the vent is 200x200mm 8 x 8 at the bottom (tapering the wrong way) to 300mm x200mm 12x8

[Tonyp]

Re: 7 years in the waiting i get to start my 42" pompeii

Page 10 has some photos of the vent opening NCMan. Looks like it is deeper than wide, with the opening 3 bricks wide. Maybe you can grind the bottom of the brick to each side and make those a bit more funnel shaped? An opening 5 bricks wide along the bottom would give you another couple inches on the opening width on each side. I think it would help catch much more smoke exiting the oven towards the outsides of the arch. Chimney height will also make a difference. Plus you are outside so a little smoke out the front isn't the end of the world