Author Topic: I ordered a WFO (Read 28246 times)

Tscarborough · « **Reply #80 on:** July 31, 2012, 07:58:43 PM »

Jet_deck · « **Reply #81 on:** August 01, 2012, 12:24:52 PM »

Any revelations overnight, Tom?

Tscarborough · « **Reply #82 on:** August 01, 2012, 12:44:04 PM »

I think I will go that route, I laid it out with the brick and it looks good.

Jet_deck · « **Reply #83 on:** August 01, 2012, 04:57:25 PM »

Tom, what keeps the refractory from just pushing the soldiers out ? Are the soldiers chamford to fit exactly together or just normal bricks touching on the front, with the gap in the back ?

Tscarborough · « **Reply #84 on:** August 01, 2012, 05:01:28 PM »

They are not chamfered, the refractory cement holds them together, the concrete keeps them from spreading. In an oven like Craig's the insulation and exterior stucco act in compression as the buttress, and they will do the same in this one, but to a lesser extent. The concrete band will act as a tensioned ring.

I hope to get the floor down tonight, traffic permitting....

shuboyje · « **Reply #85 on:** August 01, 2012, 05:47:39 PM »

Quote from: Tscarborough on July 31, 2012, 06:15:29 PM

Yes, I agree that is the way they do it, but also after observing Craig's oven I came to several other conclusions. First, the material they use for insulating is not nearly as good as perlite (the oven was too hot to touch on Sunday), but it is much more dense, they use the insulating material AS the buttress along with the exterior layer of stucco which by my estimation is a good inch (thump test), and is not reinforced by wire (looking in the cracks of the stucco).

That is why I planned to use a belt of refractory concrete (non insulating). With the brick sailored, it will maintain the planned 4-1/2" of thermal mass, and will NOT rely on the insulation/stucco as a buttress.

How did you apply the perlcrete?

I think your plan is a good one, I just misunderstood you and though you were under the impression that is how the Acunto was built.

Very interesting to hear the mix is not very insulating. I've felt for a while Neapolitan ovens are not very well insulated, this just adds to it. It also effects my opinion of the Neapolitan vent...

I built a form out of lath to hold the perlcrete in place on the vertical surfaces. I hand formed the perlcrete over the dome. I then left that lath in place and stucco'd over it. The stucco cracked in both the areas with lath and those without. Once the cracks formed the thermal expansion issue was obvious, the cracks went from hairline when cold to 1/4" wide at cooking temperature.

Michael130207 · « **Reply #86 on:** August 01, 2012, 06:02:22 PM »

Is it just the stucco that cracked or did the perlcrete crack too?

To finish my oven I was going to leave preformed perlcrete panels in place around my oven and then form the outer layer of perlcrete with forms and then stucco as you did. I was hoping the lack of bond between the oven brick and the panels of perlcrete would leave room for expansion. However if the perlcrete outer shell cracks when it expands thats another issue and my concept may not work.

shuboyje · « **Reply #87 on:** August 01, 2012, 06:17:01 PM »

nope, the perlcrete was fine.

Jet_deck · « **Reply #88 on:** August 01, 2012, 08:17:10 PM »

Quote from: shuboyje on August 01, 2012, 05:47:39 PM

... It also effects my opinion of the Neapolitan vent...

Jeff, I'm interested to hear what you think of the vent.

Jet_deck · « **Reply #89 on:** August 01, 2012, 08:18:21 PM »

Quote from: Tscarborough on August 01, 2012, 05:01:28 PM

I hope to get the floor down tonight, traffic permitting....

Me too.

Tscarborough · « **Reply #90 on:** August 01, 2012, 08:57:19 PM »

It sucked, I did get the saw set up and layout and mark the front area bricks, at least.

shuboyje · « **Reply #91 on:** August 01, 2012, 09:56:54 PM »

Quote from: Jet_deck on August 01, 2012, 08:17:10 PM

Jeff, I'm interested to hear what you think of the vent.

My oven has a Neapolitan vent, and with the oven down to the brick I could have easily tore it out. I didn't. It works, in fact it works well, but I don't feel I've seen any magical properties from it a standard vent designed well cannot provide.

For a while I've felt a lot of the properties the Neapolitans link to the vent could be directly related to lack of insulation. Heat travels from hot to cold, always. The bigger the difference in temperature the better the heat transfer from hot to cold. IF you had a poorly insulated oven that is leaking heat out the top of the dome, and you placed a Neapolitan vent on it, you would essentially insulate a large portion of the dome. I'll try to explain. Imagine you have two poorly insulated ovens. Oven A has a standard vent. Oven B has a Neapolitan vent. Let's say the brick at the top of the dome in both ovens is 1200F and the "insulation" is 200F. You have 1000F temperature difference. Lots of heat will leak out of the oven as it moves from hot to cold. That is Oven A. Oven B has a Neapolitan vent, and because of that it has a large portion of it's dome covered by hot Flu gases instead of "insulation". Let's say those flu gases at 800F. You now have 400F temperature difference driving the leakage instead of 1000F. You will lose less heat out of the dome and as a result burn less wood, and the oven will get hotter. Those are the exact things they claim a Neapolitan vent achieves.

In a well insulated oven the Neapolitan vent leads to a large uninsulated area, more complicated build, and more restriction to airflow for what gain? Potentially slightly higher draw in a hot oven roaring for sub 60 second bakes. I have no problem being a guinea pig, but at this point I don't recommend them for home ovens.

Jet_deck · « **Reply #92 on:** August 02, 2012, 10:07:26 AM »

Jeff, I agree 99% with your thinking. The only exception that I would take is that "a large portion of the dome" being covered with flue gasses. From the pictures I have seen (maybe 1) I would say that less than 1/4 of the dome is covered by the exhaust. Otherwise, I think you've got it right.

Jet_deck · « **Reply #93 on:** August 02, 2012, 10:08:17 AM »

Quote from: Tscarborough on August 01, 2012, 08:57:19 PM

It sucked, I did get the saw set up and layout and mark the front area bricks, at least.

At least you got the new saw set up.

Jet_deck · « **Reply #94 on:** August 03, 2012, 11:52:13 PM »

Tom sent an update earlier this evening; he got the floor cut, but not laid. Looks dang fine to me.

Jet_deck · « **Reply #95 on:** August 06, 2012, 08:52:55 AM »

From Tom yesterday :

"Laid the floor with heatstop/perlite at 1 to 1 ratio, the second picture is to give you an idea of the entry, 18"x9" at the outer edges, with a 3/4" revel. Tomorrow I plan on finalizing the layout and cut the sailor course, if not lay it."

Jet_deck · « **Reply #96 on:** August 06, 2012, 01:58:51 PM »

Lookin good.

Chicago Bob · « **Reply #97 on:** August 06, 2012, 02:35:12 PM »

It sure does, you got you a work horse there Gene....very nice Tom.

Jet_deck · « **Reply #98 on:** August 06, 2012, 02:50:46 PM »

Quote from: Chicago Bob on August 06, 2012, 02:35:12 PM

It sure does, you got you a work horse there Gene.

I'll be in over my head till I read the instruction manual.

TXCraig1 · « **Reply #99 on:** August 06, 2012, 03:00:34 PM »

This thread has the potential of turning into one of my favorite on the forum if the pictures keep coming. I can't wait to see the next one and the next one and the next one...