Soldier Course...Full Brick? Half Brick?

[flyfisherx]

I am seeing a mix of starting courses. Full brick, Full brick with a 20 degree angle cut, Full brick no angle, 3 half brick stack with a wedge on top, a single half brick stack. etc....

I am leaning toward a full soldier course but keep reading that this creates a weaker dome. For all the engineering types out there, is this true?

What is the best way to start my first course. BTW, I will have my floor inside the soldier course. Full course with an angle cut or half brick course.

Let the debate begin!

Thanks for the help.

David

[Lburou]

Re: Soldier Course...Full Brick? Half Brick?

If I had do-overs, I'd go with dmun's advice and lay a sailor course from the git go!

A sailor course is easier, with none of the force issues, AND it makes it easier to have the brick ends of the next course right in the middle of the lower bricks. That makes building the dome easier and will likely have fewer cracks in the dome in the end.

No question in my mind! Wish I had listened. You can make the first two or three rings vertical if you want the outer walls to allow working close to the edge of the oven floor, then begin your taper to the top.

[azatty]

Re: Soldier Course...Full Brick? Half Brick?

There are quite a few threads on arch geometry. Bottom line is that a full-brick soldier places the thrust of the arch outside its optimal position. In a large structure, tensioning chains or buttressing would be needed. That said, there a plenty of ovens built with a full soldier course that are still standing. If you have concerns, go with the half soldiers so you don't have to worry about it. It's only a little more work, and you'll have plenty of it to do.

[flyfisherx]

Re: Soldier Course...Full Brick? Half Brick?

lay a sailor course from the git go!

A sailor course is easier, with none of the force issues, AND it makes it easier to have the brick ends of the next course right in the middle of the lower bricks. That makes building the dome easier and will likely have fewer cracks in the dome in the end.

Sailor course? I never heard of that term before. I am assuming you mean something like 3 courses of half bricks layed flat then proceeding with a wedge and begin the curvature of the dome?

Something like Kebwi 36" in Seattle build?


Thanks for the response.

[azatty]

Re: Soldier Course...Full Brick? Half Brick?

There are some strange masonry terms. A brick laid vertically with the "stretcher" (thin side) facing outward is a "soldier." That's what you typically see for the first course on a Pompeii oven. A brick laid vertically with the wide side exposed is a "sailor." So a "sailor" is really just a soldier spun 90 degrees. A "header" is a brick laid on the long, wide side with the shorter, narrow side facing outward. A "rowlock" or "bull header" is a brick laid on the long, narrow side with the small side exposed. A "shiner" is a brick laid on the long, narrow side with the broad side exposed.

The masons here can correct me, but I think what Kebwi has in his oven is really a course of "headers" rather than "soldiers" or "sailors." The "soldier course" in Pompeii parlance is often used to mean the first course of dome bricks.

[Lburou]

Re: Soldier Course...Full Brick? Half Brick?

Whatever you call it....I wish I had put the big side down with the face cut inside, like your picture illustrates. You can taper the bricks, but that is certainly optional.

[GianniFocaccia]

Re: Soldier Course...Full Brick? Half Brick?

I started with a soldier course because it was the conventional (and popular) way to go. I wasn't happy with the joints so I tore them all out and went with horizontal bricks (sailors) throughout. THis is documented in my thread, here:

http://www.fornobravo.com/forum/f8/octoforno-7122.html

The benefits of a horizontal course #1 are:

1. You can can still create any interior dome profile you want (ie: first three or four courses can be built perfectly vertical)

2. You do not subject your dome to the side thrust as outlined by azatty

3. Each course benefits from gravity, making mortaring easier

4. Depending on your soldier height and angle, you may use fewer bricks

5. Keeping a perfectly staggered bond is easier and makes the dome entirely consistent.

Soldiers may make for a faster-built dome, but this wasn't a factor for me. I was looking to put together a precision dome that I could stand to look at over the years and didn't care how long it initially took me since I only have (get) to do it once. If I build a second oven, I'm with Lee, and would build it the same way - with sailors.

John

[texman]

Re: Soldier Course...Full Brick? Half Brick?

I am trying to decide the proper distance from center of oven to inside edge of the inner arch opening. I am building a 36" oven and an 18" width for inner arch. The inner arch opening can be "pushed into" the oven as close as 13.5" from the center of oven or "pushed out" so far as to not lose any of the actual floor area (see the attached 37.5 plan) So, in my 36" oven that gives me a variance of as close as 13.5" from center to 18" from center.

Is there an optimal distance from center?

Also, it seems reasonable that the vent funnel area should be at least as wide as the flue. I have drawn a 7.5" depth of funnel area for a 6" flue. Is this too much? I cant find a definite answer in the forum or plans. Many suggest to use an 8" flue for a 36" oven instead of the plan recommended 6".

I have attached two jpeg drawings to hopefully demonstrate my variances for the inner arch placement.

Bricks, tiles, and mortar are being delivered today. Thanks for any and all advice on this.

[shuboyje]

Re: Soldier Course...Full Brick? Half Brick?

I'll start with your original question. What type of oven do you plan to build? For a hemispherical oven I've personally never seen much benefit to a vertical course. For a low dome oven a tall soldier is basically a must, as is some form of structural member to support the outward thrust.

As for vent depth, it's gonna be easier to build your transition no matter how you do if the depth is the same as your flue. I agree with going as wide as the door, on my new oven my vent opening is actually wider then the door.

Finally, I would do a sketch intersecting the entry arch with the dome profile before deciding where to put it. It has been discussed before and I think the general agreement would be that is more crucial then distance from the center of the oven. The better your arch fits into the dome profile the easier it will be to build.

[Faith In Virginia]

Re: Soldier Course...Full Brick? Half Brick?

My two cents, I have no problem with my soldier course and my floor is inside my walls. Although I did buttress the exterior so I have no question about my stability.

I like having a flat wall section along the soldiers it makes raking out the coals easier but like I said it's just my two cents.

[azatty]

Re: Soldier Course...Full Brick? Half Brick?

Also, it seems reasonable that the vent funnel area should be at least as wide as the flue. I have drawn a 7.5" depth of funnel area for a 6" flue. Is this too much? I cant find a definite answer in the forum or plans. Many suggest to use an 8" flue for a 36" oven instead of the plan recommended 6".

I assume by the "vent funnel" you mean the area that goes up to your chimney/flue, right? I believe that prevailing wisdom is that you want the vent transition to be at least twice as wide as your flue diameter (be it clay or steel). So for a six-inch flue, the funnel should be at least 12 inches wide (side to side) and taper down (or rather "up") to six inches. If you can make it as wide as the whole door (18 inches in your case), so much the better. How "deep" (front to back) it should be...I don't know. Typically at least as wide as your flue. Dino has some excellent pictures on his thread of the transition to his stainless steel pipe. I have a thread showing how I did it with clay flue liner.

Also, wider flue liner is better. A wider flue can be shorter than a narrower flue and still draw the same amount of air. But if you need to build a tall chimney anyway (six feet), six inches would be o.k. for a 36" oven.

[flyfisherx]

Re: Soldier Course...Full Brick? Half Brick?

I started with a soldier course because it was the conventional (and popular) way to go. I wasn't happy with the joints so I tore them all out and went with horizontal bricks (sailors) throughout. THis is documented in my thread, here:
John

John, Thanks for responding! I have been admiring your flawless build for the past week. While all the builds on this site all offer great ideas, your build is tops in my book. The best and cleanest build in my opinion. I am only hoping to come close to the quality of your build.

I will follow your and Lburou's advice and go with the horizontal bricks (sailors). Thanks again for your help. I am sure it won't be the last question I ask.

Hey John, Did you ever finish the oven? I am anxiously awaiting further pictures of your oven build.

David