Silverton,Or. Oven

[GianniFocaccia]

Re: Silverton,Or. Oven

gmchm,

I'm happy to share the photos if they will help. The Scotch-induced self-portraits I'm not so sure about.

[gmchm]

Re: Silverton,Or. Oven

Mrchipster-I think what I mean't to say was not to use "longer bricks" but allow the cuts proceed from a 1/2 brick size to a longer length of a standard brick. It looks like this is what you are doing according to Gianni's plan. That's a clever idea for adding buttressing to the arch. Thanks very much for your input. Gianni-I think I'm starting to get my "head" around the concept. I once spent a month one summer laying out footings for a deck. I still ended up changing some of them. Luckly we have soft ground here. Thanks for the photos, I'm sure they will help. Finally! A photo of El Maestro.

[mrchipster]

Re: Silverton,Or. Oven

Beautifully done John!!

Chris

I second that. A great piece of work there I hope my oven (patterned after yours - John) will even come somewhere close.

GMCHM - I do not believe you need longer bricks I have been able to accomplish the arch with 8.375 inch bricks and my wall thickness is about 4 inches. I am building a 42 inch oven with a 12.5 inch door height, My first arch brick extends beyond the oven dome about 1.5 inches and progressively extend further and further from the dome as it goes up.

Progress photos are of my build as of today.

You can see in photo 2 that the bricks get longer - the sheet metal strip is the same width along it's whole length and at the bottom it is the length of the bricks and on the top brick shown it is about an inch wider than the metal, by my calculation the keystone brick will be about another .75 longer.

My bricks are even smaller than current standard - mine are 8.375 inches long.

The reason the left and right sides of my arch look different is that I put some triangular buttressing bricks in to the area where the inner arch extends beyond the dome I will be filling in the left sid in similar fashion soon. You can see on the left side there is a brick that I put in at level 2 that extends to the front of the inner arch by itself.

My first three inner arch bricks do not follow the design standard set by John but I was looking for a wider set of base bricks to start out my arch as that is where a great deal of stress is concentrated.

[SCChris]

Re: Silverton,Or. Oven

Beautifully done John!!

Chris

[GianniFocaccia]

Re: Silverton,Or. Oven

My conclusion is that a 42 inch oven, is that the archway needs to be set back from the opening [of say 20 inches] about 2 inchs or 5 centimeters

It took me a while staring at my Sketchup drawings to figure out what angles were at play where the dome walls converge on the inner arch plane, but you're on the right track. Its all about how deep you place the inner arch into the dome. You want to put it back as far as you can and still have the arch front protrude enough to provide you with a plane for the entryway to tie into. However, this is only the first piece of the puzzle.

What really helps in eliminating the droop, IMHO, is to cut the arch bricks to extend backwards into the dome. This way the interior profile above the arch stays intact and keeps the dome in round. Note that as the arch progresses upwards the bricks become deeper, taller, and protrude progressively inwards to match the interior profile of the oven at that level. This I learned from the pic of the fantastic Guastavino (thanks tscar) architecture displayed at New York City's Oyster Bar. These pics kinda show what I mean. The FB plans call for an arch of uniform depth throughout.

For inner arch placement, it may help to read the discussion (Round Shape) here, starting with post #121

http://www.fornobravo.com/forum/8/round-shape-14700-13.html

The drawing I was referring to (post #126 ) shows what the inner arch would look like from both the profile and plan view.

Hope this helps,

John

[gmchm]

Re: Silverton,Or. Oven

Mrchipster- Thanks for your reply. I reread Gianni's thread and downloaded his sketchup drawing, but the answer I was looking for, I think, was Sharky's photo and post where he points out that all you have to do in this arch method, to avoid the teardrop, is to use longer bricks. I had read this before, but that point hadn't registered.

[mrchipster]

Re: Silverton,Or. Oven

I have been puzzling the past couple of days about the positioning of the archway to prevent the "teardrop" effect. My conclusion is that a 42 inch oven, is that the archway needs to be set back from the opening [of say 20 inches] about 2 inchs or 5 centimeters. Is that the consensus of those that have "Been there, done that"? Thanks, gmchm

I am at chain 5 of my 42 inch build using 8.25X3.875X2.25 fire bricks and I have been following the guidance provided by OCTOFORNO - GianniFocaccia

His design seems to be a clear way to provide a nice clean arch to dome transition without developing the teardrop. I am finding that the cutting of the arch bricks it at times tedious but I believe I will avoid the dreaded sharp V bricks others have had to make. I will be starting chain 5 tomorrow and was able to join the chains to my arch for chains 1-4 today, I previously put in chain 1-4 and had not started the arch. As I said it is a little tedious cutting the arch bricks with this method as I only got 22 bricks mortared in today. By comparison I got 68 bricks done yesterday.

Transition and arch up to chain 4 completed today.

Not all my time was spent on the transition as I did cut 26 Arch bricks into their V shape and that took a while to set up and do the 4 degree cuts to both sides of a full brick. I also built the Arch form and put it in place.

Photo 1) Start of the day.
Photo 2) Start of Arch Transition
Photo 3) Me Working

Chip

[gmchm]

Re: Silverton,Or. Oven

I have been puzzling the past couple of days about the positioning of the archway to prevent the "teardrop" effect. My conclusion is that a 42 inch oven, is that the archway needs to be set back from the opening [of say 20 inches] about 2 inchs or 5 centimeters. Is that the consensus of those that have "Been there, done that"? Thanks, gmchm

[GianniFocaccia]

Re: Silverton,Or. Oven

Here in Minnesota one went through about 4 weeks ago and there is more wood than you can shake a stick at most free for pick-up

Since I just picked up day-before-yesterday a hand-operated hydraulic log-splitter via Craigslist, all I can say is:

"waaaaaaahhhhhhh"!!!!!!!!!!

[mrchipster]

Re: Silverton,Or. Oven

The real reason I reduced the size of my oven floor from 42" was a fear that the oven was too large and would require more fuel than a 39". A good number of builders here swear by their 36" ovens and the smaller an oven the more likely one is to use it.

After thinking about it, a 39" oven probably uses the same amount of wood as a 42", but cords of oak are still $350-400 in southern california.

What you need is for a tornado to go through your area... Here in Minnesota one went through about 4 weeks ago and there is more wood than you can shake a stick at most free for pick-up. You do need to dry and split it but...

Chip

[gmchm]

Re: Silverton,Or. Oven

Gianni- Wow thats a lot for oak wood. We pay about $180-$200 a cord here for oak. I had an interesting day today, if you call shifting my oven floor four times using a come-a-long as interesting. I think I have it postioned about as well as I can without tearing it part and rebuilding it. The idea I have now is inspired by an oven shown on page 44 of "A new set of WFO photos 7-25-11". [Thank you Forno Bravo folks] The photo shows a corner build with a shallow entryway and the fire brick used as the outer archway. I will have a little more room than that, but some one did a nice job. Is that a soapstone floor? gmchm

[GianniFocaccia]

Re: Silverton,Or. Oven

The real reason I reduced the size of my oven floor from 42" was a fear that the oven was too large and would require more fuel than a 39". A good number of builders here swear by their 36" ovens and the smaller an oven the more likely one is to use it.

After thinking about it, a 39" oven probably uses the same amount of wood as a 42", but cords of oak are still $350-400 in southern california.

[gmchm]

Re: Silverton,Or. Oven

Thanks again John for the concern and quick reply. My inclination is to push everything back and see how I feel after that. I remember wondering what had changed your thinking on the floor size. I intend to use the FB blanket which I think could extend over the edges a bit if necessary. I noticed a photo on the latest page of finished ovens that appeared to have a similar situation and has resolved it pretty well, [Clanton, Alabama]. I also have a photos of Les's floor and Doug's, and one of Les's finished oven.

[GianniFocaccia]

Re: Silverton,Or. Oven

gmchm,

This is a wonderful opportunity to do something you will no doubt encounter several more times over the course of your build: problem-solve. The neat thing is that at this point of your build you don't have to sacrifice much, rather plan on a couple of trade-offs. From my build I know first-hand:

1. Going with a 39" oven (instead of 42") is not only not the end of the world, it may make for a more-often used oven that is slightly easier to fire

2. It makes little sense to shortcut structural properties of your build, especially insulation

3. A less-than 14" deep entryway is very common and makes for easier oven management. I only went this deep because it gets windy at my house and I also wanted a 'holding/staging' area of my oven. Look at Les' build.

Sure, you could incorporate a decorative brick facade to accomodate the overhang just as easily as you could shorten your entryway, shift everything back (or both), or build a slightly smaller oven. Post a pic of the entire structural slab and I'm sure you'll get lots of input on a solution.

John

[gmchm]

Re: Silverton,Or. Oven

Today was another good day to make decisions, however, the day was spent in measuring and remeasuring and finially realising I had a poor idea of were the entry needed to be positioned. Once determined, I realised that I had needed not only to have read the instructions, but to have followed them. In fact there's a reason they don't show a 42 inch oven on a 62 inch corner base; it doesn't fit. Now, assuming a 14 inch minimum for the entry and chiminey, I have a 3.5 inch overhang a the corners of my fire bricks. See photo. [Thanks again Gianni] The options that occurred to me are: disassemble everthing [which is just in fireclay and sand] and move it back 3.5 inches and deal with lack of space on the back and the sides, or include the overhang in a future brick facade which would start from the ground. Does anyone have an opinion on this? Thanks, gmchm