Marino's 42" oven

[GianniFocaccia]

Re: Marino's 42" oven

Marino,
You're welcome. I just went through the same thing you did. I mortared my soldier course together in 101F heat and the bricks sucked up all the moisture. Therefore I didn't get a very good bond and they kind of fell apart. I ended up soaking my bricks and redoing it. Right after I finished it started to mist and the weather turned drizzly for three days. The soldier course is now wonderfully welded together!

You can find Les' Build by doing a forum (or Google) search. If I come across it sooner I'll shoot you over the link.

I am not knowedgeable on the proper method of securing the entryway base bricks to the floor. I was so concerned about the outward thrust of the arch on the entryway walls that I decided to go with a hemispherical arch. I will not be mortaring the base bricks to the floor.

Hope this helps. Where in CA are you?

John

[Dino_Pizza]

Re: Marino's 42" oven

Marino,
So sorry about the tear-down but you're on the right track for a better oven.

I know you said you'll do better off-setting the joints now. It will get harder to do as you go up and close up the dome. There will always be a joint that could be better, so do your best.

My oven floor (that I did not mortar to the insulation below it; I just used sand, fire clay, water and a very small dusting of mortar just as a base to keep the floor flat) ran under my side arches. So my 1st of 3 bricks for arch walls was mortared to the fire-brick floor below it.

If you are putting your 1st arch wall brick OUTSIDE your oven floor bricks, it shouldn't be necessary to mortar it in but many recently did mortar their floors down and it wasn't a problem. So brick to brick always gets mortared. Your bottom level bricks (that attach to the FB rigid ceramic insulation board OR the perl-crete insulation mix) according to the online pdf book only gets fire-clay and water, possibly sand to re-level it if needed. But you could put a very thin amount of mortar to "set" it. That bond will likely break anyway once your oven hits 900 deg and expands.

The whole thing will turn out so massive and heavy, it will never move or tip so there are no worries there.

take care, Dino

[Marino]

Re: Marino's 42" oven

It's finally starting to smell like pizza!
Sorry about the long silence. As you can see above, last October I had a major set back with the mortar and had to tear the oven down, clean the bricks and start over. I got new mortar from Forno Bravo, mixed it as instructed (or so I thought) and mortared away. The mortar seemed to be OK and by mid November I was a little farther than before; I covered the oven with a tarp and left for a 2 week vacation. I returned to the coldest, wetest fall in the Central Valley in recent memory, so it was a while before I looked at the oven again. Imagine my dismay when in mid December I uncovered the job to find that the mortar had dried to dust and there was no adhesion whatsoever between any bricks; I could just lift them up and blow the dust away, see the pictures below

[chidding]

Re: Marino's 42" oven

Wow thats terrible, Have no real idea on the causes behind mortar spalling(?)... but you should really try to find out whats going on there..

Could there be something in the water?

sad to see such issues.. i'd be destroyed if mine did that..

[Marino]

Re: Marino's 42" oven

So I spent the winter blues pondering the next course of action, like weather the oven stand would make a nice dog house with a planter on top. By late march, with nice weather again, I contacted Forno Bravo once more. This time they send me premixed mortar (just add water, about the degree of complexity I can handle in this project), and I am happy to report that this time it went well and today I finished the firebrick work after setting my 3 piece keystone. I have lots of pictures of the process that I can post if anyone is interested; here are the ones I found most interesting

[Marino]

Re: Marino's 42" oven

and a few more

[Marino]

Re: Marino's 42" oven

and more still, since there is a limit of 5 per post

[Marino]

Re: Marino's 42" oven

and finally today

[Marino]

Re: Marino's 42" oven

I found, incidentally, an easy way to cut compound angles for the different brick courses. At the beginning I used a string to measure the angles, but as the courses went up that did not work well. I set up a laser level on a tripod and marked a line on the front and back face of brick as the beam passed from the center of the oven floor to the lower outside corner of the brick. The angle is the same for all the bricks on any given course. I then aligned the laser contraption with the saw blade and platform so that the laser beam marked the blade's exact path. It is easier to do than it sounds. I used a small brick wedge to match the marked line on the brick with the beam and made the cut. My explanation sounds confusing but hopefully the pictures will clarify it. I could cut with amazing precision 20 bricks in less than one hour. Crazy complex cuts like the oven-arch transition become manageable with the same system (but are still a lot more work)

[oggi]

Re: Marino's 42" oven

Hey Marino
I just read threw this thread for the first time, you got off to a rough start but your dome is looking great, I really like your laser solution.
Chuck

[Aegis]

Re: Marino's 42" oven

Build is looking great and I am jealous of the laser technology being employed! I personally have a crooked eye ball, and I eyeballed everything! LOL So my brick joints aren't the best.
Nice vent transition, what kind of flue will you be using? Duravent or clay? And will you be building a chimney?
Again great build!
Thanks John

[Marino]

Re: Marino's 42" oven

Thanks everyone for the kind words.
I am going to go with Duratech without a brick chimney, but I am right now stuck in what to do after the FB blanket. Despite having spent months trying to decide on the type of enclosure, I still can not make up my mind. My wife likes the igloo, but I read that a lot of people have had problems with water leaking in and besides I would think the house enclosure is better for insulation; as far as a house enclosure, I really would like a flat roof but have no idea how to make it waterproof (in my mind it is like an expanded square igloo). In either case I can not see how to avoid water getting in around the steel chimney.
Another area I am having problems with is how to attach a decorative arch and face (regular red brick) to the firebrick . Any suggestions would be greatly appreciated. Thanks.
Marino

[ggoose]

Re: Marino's 42" oven

You and I are at about the same phase of construction, though I have yet to complete the chimney transition (today I hope). I will also use the Duratech. Have you drilled the holes for the fasteners yet? If so, did you have any problems with that or driving in the screws? These fire bricks seem a bit fragile to me; it seems the force of the screw would split the brick open.

Thanks, and looking good,
gene

p.s. To your question, why can't you simply build a decorative arch against your outer arch? Just mortar them together (perhaps with refractory mortar just to be safe). Seems as though it should work. That is what I plan to do after I add framing and cement board.

[eprante]

Re: Marino's 42" oven

Everybody worries about drilling the holes for the anchor plate. Just go easy and they won't crack.
Eric

[Aegis]

Re: Marino's 42" oven

Here is a link to Dino's duravent transition.
http://www.fornobravo.com/forum/8/di...html#post56009
He also has a pdf with a sketch it detailed drawing.

He opted for not drilling the firebrick for the reasons of immediately craking with either the drill and or screws. Then there is also the different rates of thermal expansion between the screws and the firebrick. Once covered and sealed, no easy way to repair!