Aceves's Corner 42" Pompeii Build

[Amac]

Re: Aceves's Corner 42" Pompeii Build

Hi Aceves - don't worry I certainly won't take offence and would not like to think I would offend anybody on here. It seems to me the most agreeable forum on the internet - free of the sniping and bitterness you see elsewhere.
I just looked back at your arch pic (attached) again. It seems looking at it that it is taller than a semicircle.

If that is the case then in order to maintain the arch to dome compatibility you would need to raise the indispensible tool the same height above the dome floor - i.e the dome centre is raised (rule 5 above )
regards
Aidan

[aceves]

Re: Aceves's Corner 42" Pompeii Build

Hi Amac,

Very true about me raising my arch; I see exactly where you're going. But if you raise your dome height (dome center), then you lose the dome to arch ratio you need for an efficient burning WFO. Remember that you need an ideal 63% dome to arch ratio. This means that a 42" oven, with a dome height of 21" requires an arch with a height of 13.25".

I raised my arch to meet this ideal ratio as recommended by the FB plans and, specifically, by builders on this site.

Aceves

[GianniFocaccia]

Re: Aceves's Corner 42" Pompeii Build

Thanks, Chris! It's amazing the quality of work one can achieve if one takes twice as long (or longer) as a professional would take!

Aceves, thanks for putting my fears at ease. I felt for sure I was stepping on your toes but was hoping to save Aiden some wasted work.

Aiden, I'm not opposed to your identical-arch-brick design. Whatever design you come up with is yours and you should be proud of it. Your logic is sound: if you make every single brick exactly the same you can build an arch with it and call it a day. You will have problems, but none that can't can be fixed with time and effort.

Because of this, don't take the time to justify your design. Just go ahead and build it. But before you do, make comparisons of two separate measurements you take: Measure the inside-facing angle of an arch brick in one of the first two courses, which are essentially vertical. Then compare that angle to the same inside-facing angle of your top-center arch brick. Because the dome curves inward at a much-shallower angle, these two angles will not be the same. Again, if you wish to adhere to identical-arch brick design, you may overcome this with some creative masonry.

I am most anxious to see how your transition unfolds, so please post lots of pics, especially when completed. My mother's half of the family comes from Knochcroghery in County Roscommon, Ireland, so two Irish blokes bangin' heads on this would be a effort in futility, dontcha think?
John

[aceves]

Re: Aceves's Corner 42" Pompeii Build

Amac,

One other thing that you might be missing, which I know I did, was that the dome slopes in at the top. So if you were to look at your completed arch from the side, then you would see an arch at a 90 degree angle from the dome floor (in profile, standing straight up). However, in this same view, the dome starts to slope in at the top, so even though the dome would butt up against the arch at the bottom, as the dome gets built to the top, the higher courses begin to slope in. This means that the dome bricks begin to move away from the arch at the very top as they slope in towards the center of the dome.

This is what Sharkey and Gianni mean by needing longer arch bricks at the top. Your arch needs to reach in to the sloping dome to meet up with the dome bricks. I couldn't see this until I started building.

Aceves

[Amac]

Re: Aceves's Corner 42" Pompeii Build

Hi aceves

But if you raise your dome height (dome center), then you lose the dome to arch ratio you need for an efficient burning WFO. Remember that you need an ideal 63% dome to arch ratio

You're right Aceves - you spotted the flaw. I was aware of that and maybe I didn't place as much importance on that ratio as I should. But this was my thinking.

I didn't want the arch opening wider that 21" - for a 39" dome. It seemed too wide. To maintain a 63% ratio for a semicircular arch in a 39" dome the arch would need to be 24.56" diameter.

But if I maintain an arch diameter 21" (10.5" height) on a dome of 39" (height 19.5") the ratio will be around 54%.

I did read somewhere on this forum that the ratio is not that strict (was it 59% to 65% someone suggested) but 54% is a bit low and maybe also the arch is a bit low.

When I raise my arch (and dome) by 1.5 " I will improve that ratio a little:

New arch height: 12"
New dome height: 21"
New ratio: 57%

To completely recover to 63% I would have to raise the dome and arch by just under 5" but I don't want a dome that height so what I propose to do is this.

From the course above the arch until the dome apex - I will reel in the height of each course by shortening the IT a few turns at each of the final courses. I would hope to recover at least a half an inch over the latter courses by this. Maybe that's optimistic since most of the height is gained on the lower courses - but anyway I will live if needs be, with 57%

So with an arch height: 12"
"reeled in" dome height: 20.5

which gives a ratio of just a fraction under 59%

Sorry again for these ramblings - you did force me back into googling percentages - and thanks for that - and the advice to get on with it. I am doing some cutting and using your 5" 4" angled single cut for a few rows, but the weather here is well Irish weather. The Latin for Ireland is Hibernia which comes from the word for winter. Legend has it the Romans never settled here because of the weather. They took one look at the weather here, named the place "winter" and headed off for sunnier climes.
Best regards
Aidan

[Amac]

Re: Aceves's Corner 42" Pompeii Build

Hi Gianni

My mother's half of the family comes from Knochcroghery in County Roscommon, Ireland, so two Irish blokes bangin' heads on this would be a effort in futility, dontcha think?

Knockroghery I know it well - it is as we say here just "back the road" about 15 miles. Have they still family there? If so they will know Murrays pub. and a few others but Murrays is the best known. Knockroghery was where they used to make "dudeens" or clay pipes that old women used to smoke at wakes back in victorian times even later because my mother remembers the custom.

Measure the inside-facing angle of an arch brick in one of the first two courses, which are essentially vertical. Then compare that angle to the same inside-facing angle of your top-center arch brick. Because the dome curves inward at a much-shallower angle, these two angles will not be the same. Again, if you wish to adhere to identical-arch brick design, you may overcome this with some creative masonry.

I think I see what you mean but I think about it like this. The bricks are rotating as they climb. The bottom arch brick will be flat so there it is vertical. But as they climb, the angle between the arch itself and the inner face which itself is about 115% (It will vary a litlle depending on the oven diameter) will naturally cause that tilt to occur until at the top it is 115 degrees. It is just that angle sweeping around like a cone segment.

What is changing is not the brick angle cut but where in each brick you measure that angle. At the bottom brick you are looking at a brick laid flat and measuring an angle directly accoss it upwards - so 90 degrees or 0 degrees tilt inwards. As you go up the bricks rotate but you are still measuring the angle "vertically" so it will be varying diagonals across each brick until at the top when you will see the full tilt inwards of about 25 degrees because you are measuring the brick as it is standing up.
Is this what you mean?
regards
Aidan

[SableSprings]

Re: Aceves's Corner 42" Pompeii Build

I did read somewhere on this forum that the ratio is not that strict (was it 59% to 65% someone suggested) but 54% is a bit low and maybe also the arch is a bit low.

When I raise my arch (and dome) by 1.5 " I will improve that ratio a little:

New arch height: 12"
New dome height: 21"
New ratio: 57%

Aidan

I built my 39" (slight tear drop shape) dome and ended up with a 20" internal height to 11.5" opening for a "non-magical" 57.5% ratio. I was a bit concerned initially with the difference between my oven and a "perfect" 63% ratio, but I've put over 1,200 loaves of bread on that hearth and they've all baked beautifully... and all get eaten with glee... and no one asks about the ratio. To paraphrase Charlie Papazian's "relax and have a homebrew" mantra now I just "relax and enjoy my WFO". My oven may not be as efficient as it could have been with a 63% ratio, but it works great for me...and I suspect your WFO will work great for you.

[GianniFocaccia]

Re: Aceves's Corner 42" Pompeii Build

Have they still family there?

Not that I know of. My mother's grandfather left for America and the rest is history, although I'd like to go back one day to see what it looks like.

At the bottom brick you are looking at a brick laid flat and measuring an angle directly accoss it upwards - so 90 degrees or 0 degrees tilt inwards. As you go up the bricks rotate but you are still measuring the angle "vertically" so it will be varying diagonals across each brick until at the top when you will see the full tilt inwards of about 25 degrees because you are measuring the brick as it is standing up.
Is this what you mean?

Yes. The angles of the arch brick face get shallower in each successive course - in your example it goes from 0deg to 25deg. Because the top-center brick has the shallowest angle, it 'rises' the least of all. If one makes all of his bricks the same size, this lack of 'rise' will certainly contribute to droop. To compensate for this each brick face was cut 'taller' as the arch progresses upwards. This is easy to see in the pic with my arm in it. To prove it works, the full frontal inside pic of the arch shows bricks that appear to be all the same size.

Does that help?

Gianni

[Sharkey]

Re: Aceves's Corner 42" Pompeii Build

I spent a bit of time thinking about this and came to the conclusion that Amac is right. If you do have a semi circular arch the bricks can be the same. I finally worked out how to visualise this. In the sketch attached the long side of the triangle is the indispensable tool marking the position of the first arch brick. Now imagine that the red triangle is a solid piece of plywood. If you pick up the left hand corner and flip the board over so that the triangle is to the right of the centre line you will have traced a semi-circle with the corner that is the end of the IT.

From the experience with my oven and the others using similar I know that the arch bricks need to increase in depth as you climb up the arch. But nobody has used a true semi-circular arch and the reason that I came up with has already been mentioned ? you end up with an opening size that is not quite right. But even though we are all following the same set of plans we all end up with very different ovens and they all seem to work ? as long as you end up somewhere in the ball park regarding the opening width and height.

I think it will work in the end, particularly if you do manage to reel the height in a bit. I did the same with mine ? adjusting my IT a couple of times after I had reached the top of the arch. Just remember that once you make the first adjustment the bricks will no longer sit in the right-angle of your IT as you have increased the rate of change of the angle.

As somebody said before ? just start building it. And start your own thread and post plenty of pics.

[Amac]

Re: Aceves's Corner 42" Pompeii Build

Hi Gianni
I never stop being impressed with that dome of yours. It won't be surpassed.
I think I know what you mean by this "droop" . Is it caused by a sort of optical illusiom. I am expecting to have some tricky cuts when I come to attaching the wall bricks to the arch - especially higher up.
BTW I went ahead and cut all my arch bricks identically (well as identically as I could manage with the angle grinder - no tapers so a lot of mortar will be used, but - and don't laugh when I say this - all identically wrong I used a template from a life sized sketch like this attached which illustrates the system I used to get the "correct" pentagon shape.
It doesn't look like much and I could probably work away with it. I couldn't face cutting another set!
Pardon the picture quality - I use the phone cam and bluetooth is handy to upload. I made the red one instead of the shaded pencil version and it changes the angles which are not right angles one gets smaller and the other gets bigger.
Sorry for bugging you guys on that arch stuff. I will need your help later on more critical thiigs - and like someone else said here - I'll make a bunch more mistakes to contribute to the learning process
thanks again
Aidan

[Amac]

Re: Aceves's Corner 42" Pompeii Build

Hi Sharkey

I spent a bit of time thinking about this and came to the conclusion that Amac is right

A convert I don't think it is really much of a deal to be honest. I was looking to make as easy cuts as possible. But it is all very well in theory, but I still messed up in practise, as I said to Gianni above, although the mistake was the opposite of what I described - I have no idea how I managed to do it, but I think I can recover it.

What convinced me immediately and unshakeably was to visualise a completely spherical dome with a completely circular "arch". Then you see immediately that every part of it must be the same. Somehow dividing it in half makes it confusing.

It follows then that many of the problems that show up are actually due to the arch getting "pushed out of its integrity with the dome.

Just remember that once you make the first adjustment the bricks will no longer sit in the right-angle of your IT as you have increased the rate of change of the angle

Good point - I hadn't thought of that. There is always something. It won't come as a shock to me then.


And yes I really must start building - and my own thread - but weather here is still a bit unsettled - and today I am going to look for some tarpaulin and maybe a chaep Gazebo.
Next

[Amac]

Re: Aceves's Corner 42" Pompeii Build

Hi Sharkey

I spent a bit of time thinking about this and came to the conclusion that Amac is right

A convert I don't think it is really much of a deal to be honest. I was looking to make as easy cuts as possible. But it is all very well in theory, but I still messed up in practise, as I said to Gianni above, although the mistake was the opposite of what I described - I have no idea how I managed to do it, but I think I can recover it.

What convinced me immediately and unshakeably was to visualise a completely spherical dome with a completely circular "arch". Then you see immediately that every part of it must be the same. Somehow dividing it in half makes it confusing.

It follows then that many of the problems that show up are actually due to the arch getting "pushed" out of its integrity with the dome.

Just remember that once you make the first adjustment the bricks will no longer sit in the right-angle of your IT as you have increased the rate of change of the angle

Good point - I hadn't thought of that. There is always something. It won't come as a shock to me then.


And yes I really must start building - and my own thread - but weather here is still a bit unsettled - and today I am going to look for some tarpaulin and maybe a chaep Gazebo.
regards and thanks for the comments

Aceves _ I am officially handing back this thread - and my next comments will be on my own - must get a good name mmm...
regards
Aidan

[GianniFocaccia]

Re: Aceves's Corner 42" Pompeii Build

I spent a bit of time thinking about this and came to the conclusion that Amac is right

I agree. Sharkey, the graphic of your approach to building a hemispherical arch with identical segments (you too Aidan) is spot on. This is the approach that I used to build the outside of my inner arch. Where I ran into a boatload of challenges is in designing the inward-facing arch bricks to match both the horizontal and vertical curves of the oven, essentially becoming a convex extension of the dome itself. This is where I believe each brick must be different, and not applicable to arches that are built in a single plane.
Gianni

[aceves]

Re: Aceves's Corner 42" Pompeii Build

Here's an updated photo of my build. Finally covered the roof with cement board and finished all my electrical. Not the cleanest board cuts, but stucco will cover all my errors!

The box you see on the right will house an amplifier and my MP3/iPhone for music. The piece of board on the top left covers a round opening where a marine full-range speaker will go, and below left is an outlet. I will be installing 2 marine speakers (all-weather), 2 outlets, and one switch for my lights. I'll be doing the walls in stucco. Haven't decided on the roof materials yet.

Aceves

[aceves]

Re: Aceves's Corner 42" Pompeii Build

So I have a few extra firebricks left over from my build (quite a few extras actually!).

I decided to "mod" my WFG - Wood Fired Grill - that will be incorporated into my outdoor build of the WFO.

Here's a pic of my "mod": I lined the bottom of my grill with firebricks. The idea is that once I fire up my grill, the bricks will soak up the heat from the fire and keep my grill going hotter, longer. That's the idea, anyway.

I have seen a few grills on the internet that are lined with firebricks, so I'm not too far off course, right?

What do you all think?

Aceves