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-   -   4 courses up... and a big question (http://www.fornobravo.com/forum/f2/4-courses-up-big-question-3333.html)

Throw Deep 02-09-2008 07:34 PM

4 courses up... and a big question
 
I'm having a "sinking spell" and need some advice asap.

As the title says, I've got 4 courses up on a 36" oven and it is looking great. This is my first attempt to lay brick and am coming on up the learning curve...but I'm feeling pretty stupid at the moment. Somewhere along in the third course I started noticing gaps between the bricks (the invented "V" so...I started buttering the side of each brick with Heat Stop in addition to the bottom before setting it.

Now showered and tired after a full day of laying brick I've been thinking about those cracks. So I go out and set a light in the center of the oven and, dang it, I can see the light shining through those cracks between some of the bricks.

My question...is this a problem...meaning I have to tear it all out and start over or will the insulation coating render my problem...not a problem at all?

Ken524 02-09-2008 07:36 PM

Re: 4 courses up... and a big question
 
Throw Deep,

Can you post some pictures for us to look at?

Dutchoven 02-09-2008 08:48 PM

Re: 4 courses up... and a big question
 
Definitely post some pictures...there very likely is a workable solution other than tear down...Dutch

Throw Deep 02-10-2008 10:28 AM

Re: 4 courses up... and a big question
 
I'm not sure if this link gets you to pictures but I think it will. Thank you for your help.

Bob


Picasa Web Albums - Robert - Pizza oven

Acoma 02-10-2008 10:43 AM

Re: 4 courses up... and a big question
 
Cracks between bricks, not within the bricks is nothing. Yes, mortar those areas, clean them after a few minutes, but do only a couple bricks at a time or you will be further frustrated. As for the inverted V, you will need to photo a spot so that proper advice can be given. With the inverted V, Ken has posted ways to handle it, I believe after his 7th course? Let's say you have the V, eyeball the gap and bevel the top to bottom of each brick connecting them. Example is .25 gap at bottom needs to have .125 shaved from each top corner wall. Again, check out Ken's gallery for further clarification too. Lastly, photo these issues for us to better help you.

Acoma 02-10-2008 10:48 AM

Re: 4 courses up... and a big question
 
Sorry, just saw your Picassa. You don't need to sweat things. Do go back and mortar the inside areas to create a flush wall, and clean as you go.

As for the outside wall, I prefer to have my mortar flush with bricks as I go as well, and you can do that too. You have 1-2 days of clean up to do with this.

Give the mortar a day to cure, then find your dome floor center. Once found, be sure your dome is circular for each course. You may not be at the arch, but worry about that later. For now, you can use a marker, or whatever, with a string for consistancy, and mark irregular spots. Once done, use your grinder and carefully shave the walls to create the nice round dome wall. Trust me, better now, then further issue later. I have done it on my 6th and 7th course and am glad I did.

Throw Deep 02-10-2008 05:53 PM

Re: 4 courses up... and a big question
 
Thank you Acoma, Dutch and Ken...it's a relief that I don't have to knock down and re-build the walls. I pointed the gaps inside and out and worked on the "high spots" with my new grinder...which Acoma gave me an excuse to get...I've wanted one for a while. I've been using the string method from a center pivot so I'm fairly round and level. I'm planning on marking and grinding inside edges as I go up on each course.

The cuts on the bricks are okay so far but cutting out that "inverted V" may be beyond my capacity.

The current plan is to use 2 or 3 FB insulating blankets and add a few more inches of vermiculite/portland mix over the resulting dome. Hopefully that will seal up any small air gaps if there are any left.

One other question for down the road...when curing through a progression of fires...should it be cured before the insulation is put on or after...or does it matter?

Bob

asudavew 02-10-2008 05:58 PM

Re: 4 courses up... and a big question
 
Quote:

Originally Posted by Throw Deep (Post 23939)

One other question for down the road...when curing through a progression of fires...should it be cured before the insulation is put on or after...or does it matter?

Bob

Probably the most debated question on Fornobravo.
Either way is just fine.
But if you want to patch any cracks that could form during curing, just use a blanket so that it can be removed for repairs.

Dave

Ken524 02-10-2008 06:29 PM

Re: 4 courses up... and a big question
 
Looks like you have it under control, Bob.

Just remember to butter the sides of the bricks from here on out so any "V's" that you have are filled with mortar. When I did mine, I would butter the top of the previous course then the side of the new brick. Tap the new brick into place until mortar oozes out those cracks then clean it up with damp sponge after it sets for an hour and you'll be good to go.

(Beautiful pool back there!)

gjbingham 02-10-2008 06:47 PM

Re: 4 courses up... and a big question
 
I buttered the bottoms and both sides of each brick when I laid them, but I did not custom cut the majority of my bricks. I look at mortar as just being a solid space filler that mimimizes the possibility that a brick can move in any direction. I may be totally wrong, but I believe the actual bond strength of mortar to brick is very very low. Therefore, at least in my small mind, full mortar joints reduces possible brick movement problems related to thermocycling. (That said, you could easily make an arguement for leaving spaces to allow for brick expansion/contraction and I might believe you :) )

Make sure that if at all possible, you don't allow mortar joints to line up anywhere between rows. Almost all my cracks occurred at areas where the mortar joints were within an inch or so of the next row.

As far as the existing gaps in the mortar, I'd make a wetter mix and finger it into those voids, or spend 5 bucks on a grout bag and attempt to force it into the bigger ones.

The lower courses are almost vertical, so it may be that their strength due to the sheer weight of the bricks in a downward didrection will not be affected by voids, especially if you use cladding on the outside. There's a couple of discussions in this forum about failures of arches. If memory serves, it's somewhere in the middle third. That is where I'd get serious about structural integrety. - my advice, to be taken with a grain or two of salt.


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