36" Pompeii in DC

[rsandler]

Re: 36" Pompeii in DC

After closing the dome on Wednesday, while my in-laws went out sight-seeing, I started working on my vent arch. This ended up being a bit more work than I expected, and I ended up having to finish it in the evening, and left s-curve for the chimney incomplete.

Thanksgiving morning, I took a few minutes to remove the forms, and clean up the mortar from the arches and the debris from around the oven. To my everlasting surprise, the arches stayed up!



Today, with the in-laws having gone home, I finished off the chimney base, such that it's ready for a flue to go on.



I must have mis-calculated somewhere, because instead of the opening being almost 10" across side-to-side at the top, it's only a bit over 5", giving me an opening slightly larger than 5"x6"


Still, since my oven opening is just over 200 square inches, a vent of just over 30 square inches comes to right around the 15% ratio that seems to be recommended. Given that I'm planning on putting a relatively tall flue on top of the thing (haven't figured out whether to go ceramic or stainless, round, square or what), I think/hope it will draw just fine.

If I'm wrong about that, someone let me know! I could still knock the top couple of bricks off and shave them down or something.

Cheers!
-Ryan

[UtahBeehiver]

Re: 36" Pompeii in DC

It is a nice feeling of accomplishment when the plug goes in. Congrats and nice looking inside.

[rsandler]

Re: 36" Pompeii in DC

Haven't had a chance to make a post in a few days, and a lot has happened. First and foremost, *drumroll*

the dome is done!

I got off early on Wednesday ("early release" they call it, I guess for good behavior?) and placed the capstone while my wife and in-laws looked on.




Since this was only moderately exciting for the audience, I followed up with the comedy section of the afternoon and cleaned up some remaining mortar from the inside of the oven.



Totally stoked to have finished, and to have done it by my crazy goal of Thanksgiving. And many thanks to the folks on the forum for all the help--I intend to keep asking for more as I work on the chimney, enclosure, counters etc.

Cheers!
-Ryan

[rsandler]

Re: 36" Pompeii in DC

Went out before work and picked up three rolls of insulating blanket from the local HVAC store. I somewhat accidentally managed to bargain for a good price on them too. Before I headed out, I checked the price with shipping to get 3 rolls of FB Blanket from our host, and worked out that it would be about $350. Got to the store, found that they were charging about $200 (!) per roll for 1" Inswool. I kept saying (honestly) that I'd rather just order it from FB, and the guy at the store kept coming down in price, until he offered all three rolls for $350. Also picked up some ceramic moldable caulk to use for a heat break between my entry and vent arches.

[rsandler]

Re: 36" Pompeii in DC

Finished the 11th full course yesterday (not counting the soldiers), and, upon determining that another full height course was just not going to fit, set about cutting a three-piece plug:



I actually ended up removing the mortar today as I continued to trim the plug to fit, and realized that the 1/4" of the two mortar joints was most of what was standing between me and being done with the silly thing. The pieces fit so snugly that I had a hard time getting them back out after the last fitting, so the lack of mortar between them shouldn't be a problem. I could have mortared in the plug today, but I decided last week that I would make the plug but wait until Thanksgiving to put it in. Seemed festive .

Finishing the last course also meant finally removing my long-suffering, low-budget Indispensible Tool, which looks a little worse for wear now. To give you a sense,
Before:


After:


A couple more pictures of the finished course attached.

[rsandler]

Re: 36" Pompeii in DC

Still seems like you could flip the brick front to back

There probably was a way, but I messed with it a while and couldn't find one. I did end up finding a work-around, where I cut several bricks as far as they would go, then raised the blade way up and stood the brick on end to cut the bit that I couldn't get lying down. I tried to cut the angle so that I wasn't tapering the whole brick, just as much as the saw could cut through. In practice I ended up with some lips, which I mostly decided to ignore. The face with the mortar joint doesn't need to look pretty!

[deejayoh]

Re: 36" Pompeii in DC

Ah, I see. Still seems like you could flip the brick front to back

[rsandler]

Re: 36" Pompeii in DC

The problem isn't the hub (which is easy enough to get out of the way by raising the blade), but the very back of the blade guard, near where the water tubes connect. Not a problem for cutting a piece that's 4.5" front to back, but the full 9" brick hits it. To get the back of the guard out of the way I'd have to raise the blade up as high as it will go, at which point I'm only cutting half an inch of the brick :P.

[deejayoh]

Re: 36" Pompeii in DC

Raise the blade up a bit, and you should be able to get through most of the 4.5" brick before hitting the hub.
Then what I did is flipped the brick around and eyeballed the bit that was left.

[rsandler]

Re: 36" Pompeii in DC

Quick question for the forum: I started trying to taper the bricks for my vent arch, and discovered that my saw can't handle a 9" long, 4.5" tall brick--the top of the brick bumps the back of the blade guard before the blade has made it all the way through the brick.

Occurred to me that I could just cut the bricks down, make them 9"x3" or so, and then both the brick would fit under the guard and I could probably do the tapers with one cut. This would mean that my arch was 3" thick rather than 4.5" thick, however. Any reason that would be a terribly bad idea?

[UtahBeehiver]

Re: 36" Pompeii in DC

Looking forward to seein the final product. If I remember right, Tscar posted some info on vent opening to vent size ratios. I just can't remember the exact link.

[ATK406]

Re: 36" Pompeii in DC

I like the 'S' curve. It looks very elegant. I acheived a similar though less sensual shape by cutting a single brick (for each side) at an angle (lengthwise) and then used the two peices to form a smooth transition to the flue. I think the fact that the two pieces had complimentary angles helped the aesthetics and it required minimal mortar to create the transition I wanted.

The 9" x 6" openning should be ok - maybe a little smaller than mine. I used a an 8" x 12" rectangular flue liner which measured 7 3/4" x 11 1/2" on the inside so I made my vent openning more or less the same size. However I built a 42" oven so I don't know if that has any bearing on the flue size...I doubt it should change too much. BTW my chimney vents very well with barely a puff of smoke escaping when I first fire it up. As soon as the chimney starts to warm up (5 seconds later) up the chimney she goes. She being the smoke of course.

I can't give you any advice on the buttressing though. I did not buttress my arch/chimney but I only have the weight of the clay flue liner resting on my arch. I will support the exterior brick of my chimney with a block and steel structure (next year .)

Whatever you decide to do I'm sure it will turn out very nice - based on the work you have already done. You're in the home stretch now. Can you say WFO Turkey for Thanksgiving?

[rsandler]

Re: 36" Pompeii in DC

Probably getting ahead of myself, since the next course should be a doozy, but I'm thinking ahead to the vent and chimney design.

I've had it in my head for a while that I wanted to do an S-curve sort of transition, (See attached pictures, front, top and back, respectively). As pictured, this would give me a roughly 9" by 6" opening to put a flue on top of. I'm planning on the chimney being at least 5 feet high to allow smoke to clear the deck.

Questions: Is that too large of an opening?? Or rather, is that more than necessary, such that I could have the full arch in front be thicker and thus stronger? If I go with this S-curve idea, will I need to buttress to support this arch, whereas if I just had an opening and built on top of it this wouldn't be necessary?

Cheers!
-Ryan

[ATK406]

Re: 36" Pompeii in DC

Your build looks alot like mine. At this point I abandoned the props I was using to hold the brick in place and used an inflatable rubber ball to hold my final course (which I cut to half thickness). I was fortunate to have a 12"x12" piece of FB left over from my hearth. So my keystone was a large plug. It took a few hours to trim it down to size with a taper to fit the hole in the top of my oven but that included time spent to put an inscription on the side that would be facing the inside of the oven.

Like so many other parts of this project, there are many ways of getting it done and it basically comes down to the materials you have on hand, your preference and most importantly - execution. Good luck on the rest of your build.

[Les]

Re: 36" Pompeii in DC

My rough measuring tells me that I could either do one more course and a large plug, or two more courses and a really tiny plug. I'm leaning toward the former--if I do a 12th course I don't think I'll be able to use my IT, and I've really come to rely on the thing!

Ryan,

I went up 12 then the plug - it looks like you will need to do the same. Again, great work!

Edit... it looks like you are at course 11 right now - 1 more and you are golden.