Napa WFO dome & hearth build questions

[EricU]

Re: Napa WFO dome & hearth build questions

Got a little further on the WFO, hope to top out the chimney and get the insulation in and the roof on this Saturday.

I really want to start using it again but am determined not to until I finish it -- well at least finish the rock work and get the roof decked in and water tight!

[EricU]

Re: Napa WFO dome & hearth build questions

Turns out I only had room for one full size liner with my transition pieces.

Had to tarp the top yesterday and get ready for our brutal Northern California winter storm that is supposed to be hitting tonight.

The front facade and chimney are taking longer than I thought but I am fired up (bad pun) on finishing this thing now, and it is fun to see some of the other builds going on. No more WFO chicken, lamb or pizzas until I get up over the roof!!!

And Cheesesteak, NICE looking build!

Eric

[Cheesesteak]

Re: Napa WFO dome & hearth build questions

Eric - I don't know the answer to your question . . . but -

I don't think it can hurt to go with the larger sections on the bottom. Fireplaces generally have a larger flue where it meets the firebox - but that's generally to create a smoke chamber. The key is getting a good draft going up the chimney. I would think that the lager flue at the bottom would aid in the initial draw of warm air from the oven - you'd have twice the area (8x17 v 8") to capture warm air when you light the fire.

But - whaddo I know???

[EricU]

Re: Napa WFO dome & hearth build questions

Eric -

You may be past this already - but I originally tried a 6" clay flue liner and ended up removing it and going with a 9x13 liner. It really draws nicely...

I haven't installed my flue pieces yet and will take the 8" diameter section which will be cut down from my 8x17 ovals up above the rafters. Then I will give it a test fire and see what happens???



I do have the option of running two full size uncut 8x17 oval sections then go to my cut transition pieces or just one 8x17,

• Does anyone know if it is better to have a larger flue or to transition to the final diameter as soon as possible?

Thanks, Eric.

[Cheesesteak]

Re: Napa WFO dome & hearth build questions

Eric -

You may be past this already - but I originally tried a 6" clay flue liner and ended up removing it and going with a 9x13 liner. It really draws nicely.

To encase the chimney flue - I wrapped the full length with leftover insulating blanket and made a cement-board sheath that ended up as the outside of the chimney. Just did a stucco finish. Dozens of oven firings and it draws perfectly fine and the outside of the chimney (stucco) doesn't get hot at all.

Nice looking build - by the way.

[EricU]

Re: Napa WFO dome & hearth build questions

[QUOTE=deejayoh;140361]Looks like you've got some cat5, coax, fiber, and about 220volt panel wired into that thing!...QUOTE]

Just a 120V dedicated outdoor circuit and a bunch of switch legs for a lot of different lamps hanging off the thing. I am tired of asking my kids "Where's my flashlight..." as it gets dark early here in Northern California during our brutal winters!! I also wired the upper eaves for speaker wires to connect to a Sonos system.

I really want to get it finished up now that I am working on it again and will not fire up the WFO again until I at least get the chimney stack proud of the rafters. So until then, we are eating chicken off the BBQ, and no pizzas!! (talk about roughing it)

Eric.

[deejayoh]

Re: Napa WFO dome & hearth build questions

Looks like you've got some cat5, coax, fiber, and about 220volt panel wired into that thing!

I like the finish though. And that is quite a chimney design. 8" interior on 42" should draw well.

[UtahBeehiver]

Re: Napa WFO dome & hearth build questions

Eric,

Like the mix use of materials and the outside the box organic look to the panels.

[EricU]

Re: Napa WFO dome & hearth build questions

I got a little farther yesterday. I didnt have time today as I was acid staining my driveway and front walk (why not?)

The two side and rear panel pieces are complete, the rough wiring is in and I got the flue transition pieces kind of figured out.

I was able to get the WFO flue transition pieces to the point that my brick laying is now flat and on the same plane, so I don't have to split bricks, just cut them to size. Got a couple of decent size rocks mounted and supported.

I called one of my local mason's supply yards in town and asked about 8" diameter round clay flue liner. They said they could order it and all they had was some 8x17s, I decided to get them and modify them. There is a pic below, they came out better than I had expected.



I am moving the flue liner riser to the right to clear my ridge beam with a series of angled cut bricks, the angles are more than degrees which is probably more than fuild dynamics would like but;

1. I needed to get it moved over quickly without losing too much height
2. It has been a long time since I was in college and had fluid dynamics and we will just see how it draws!

[IMG][/IMG]

[EricU]

Re: Napa WFO dome & hearth build questions

These photos may help show my situation.


Thanks for any help! Eric

[EricU]

Re: Napa WFO dome & hearth build questions

Soooo... I finally am getting around to (hopefully) finishing up the WFO portion of my backyard. Looking back, I think I started it around May 2010, been using it to cook chicken, pizzas, lamb, vegetables...etc, etc...blah, blah, blah.

Anyway, I am going to try to make the transition to the chimney tomorrow.

Going to pick up some 8x17 oval clay flue liners tomorrow, cut them and put them back together as an 8" circle, then wrap them with the "money shot" bricks/rocks.



Should I:

1. Fill the gap between the flue liner exterior and the inside of the brick chimney with Pearlcrete?
2. Leave the gap empty?
3. Wait another two years to start the chimney?

Thanks for any help! Eric

[david s]

Re: Napa WFO dome & hearth build questions

Soooo.... Would a 6" or 7" flue liner work?

I was thinking of either using;


2) A cheap metal stove pipe (6" diam. single wall) and using it in the same way, basically it would be a form left in place for the pearlite.

Any ideas? Comments? Winning lotto numbers?

Eric.

Be careful, if going for this idea. What will happen when the cheap stove pipe corrodes away? your perlite will pour down the flue if placed in dry. Or if you have mixed cement with it, then it will probably break down, crumble (portland cement is only good for 300 C, perlite OK below 1100 C) and pour down your flue. Your first solution would be a safer alternative.

[Tscarborough]

Re: Napa WFO dome & hearth build questions

I did A, but have seen it done like B, but the metal was removed and the perlcrete was parged with refractory.

[EricU]

Re: Napa WFO dome & hearth build questions

...For an 8x8 OD flue, your actual cross section is closer to a 6-1/2" ID round flue...

Soooo.... Would a 6" or 7" flue liner work?

I was thinking of either using;

1) A clay flue liner and leaving a gap between it and the "Money Shot" bricks, rock etc and filling the void with pearlcrete.
2) A cheap metal stove pipe (6" diam. single wall) and using it in the same way, basically it would be a form left in place for the pearlite.

Any ideas? Comments? Winning lotto numbers?

Eric.

[Tscarborough]

Re: Napa WFO dome & hearth build questions

When calculating the cross section of a flue, you consider them all to be round or oval, and do not count the corners. For an 8x8 OD flue, your actual cross section is closer to a 6-1/2" ID round flue. Flue tiles are normally measured OD for square and rectangular shapes, and ID for round flues (since they are considered pipe, I guess).