#1  
Old 03-15-2008, 05:53 PM
Laborer
 
Join Date: Feb 2008
Location: Melbourne, Australia
Posts: 60
Default External crack

Oh no!

Fired the oven last night (see pizza photos in photo bragging section) but just as the fire was finished and burning down the oven render cracked. The crack is only in the final waterproofing render that i put on last weekend (7 days ago). So I guess I fired too hot - too soon

Also thought that maybe the render was too thin, only about 1-1.5".

The crack started at the flue and then slowly worked its way all the way down to the arch. It is only hairline down by the arch but about 1/16" up by the flue.

Any advice on how to repair?
Do I need to render the entire oven again or just the front section?\
If I leave the crack and tile the front would that work?

Help!

Thanks
Attached Thumbnails
External crack-crack-1.jpg   External crack-crack-2.jpg  
Reply With Quote
  #2  
Old 03-15-2008, 09:25 PM
Dutchoven's Avatar
Master Builder
 
Join Date: Apr 2007
Location: Mississippi
Posts: 931
Default Re: External crack

I might suggest using the oven for a while...maybe crack will stabilize...mark it with a pencil to see if there is any movement and watch it when the oven is firing and when it gets hot to see what it does...any widening and where etc...then you will have a better idea of what to do.
Dutch
__________________
"Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that's creativity. " Charles Mingus
"Build at least two brick ovens...one to make all the mistakes on and the other to be just like you dreamed of!" Dutch
Reply With Quote
  #3  
Old 03-15-2008, 10:28 PM
gjbingham's Avatar
Il Pizzaiolo
 
Join Date: Sep 2007
Location: Longview, WA
Posts: 2,021
Default Re: External crack

I agree with Dutch. Did you add stain to the rendering material or did you paint afterwards?

If it doesn't get worse, I might be tempted to take a grinder and open the crack up and refill it again. I forget. What's the insulation like below this layer?
__________________
GJBingham
-----------------------------------
Everyone makes mistakes. The trick is to make mistakes when nobody is looking.

-
Reply With Quote
  #4  
Old 03-16-2008, 12:30 AM
Il Pizzaiolo
 
Join Date: Dec 2006
Location: Mishigame & Iberia
Posts: 1,168
Default Re: External crack

Those pesky cracks

I think we're still looking for a dome that has not cracked. I would also be interested in hearing of someone has had good success with grinding out a crack and filling it.

With the continued expansion and contraction of these ovens and fireplaces, are cracks just a part of life?

I had an indoor fireplace and never was able to successfully fill an exterior crack on that one. (never ground it out though) And I do have two exterior cracks on my oven now. I've filled them a few times and painted over. Recently I tried an arcrylic caulk (more flexible).

Reminds me of a song....

Oh, the crack came back
It wouldn't stay away
The crack came back
The very next day

Dutch has it right too, give it time to grow (if it's going to) and stabilize
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Tiempo para guzarlos.....
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
...enjoy every sandwich!
Reply With Quote
  #5  
Old 03-16-2008, 12:46 AM
Il Pizzaiolo
 
Join Date: Dec 2006
Location: Mishigame & Iberia
Posts: 1,168
Default Re: External crack

Then I read Frances post on her Ostrich......

No bacon today,
the bacon's gone away,
sad as it is to say,
the bacon's gone away

...sorry, I was out on the oven today and seem to to have got stuck in singing mode. Let me know what you think if you try it!

>
>
>

Frances, this is too funny.....

I think we were both humming the same tune!!

.....another FB cosmic connection
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
Tiempo para guzarlos.....
To view links or images in signatures your post count must be 0 or greater. You currently have 0 posts.
...enjoy every sandwich!
Reply With Quote
  #6  
Old 03-16-2008, 01:36 AM
Frances's Avatar
Il Pizzaiolo
 
Join Date: Aug 2007
Location: Allschwil, Switzerland
Posts: 2,186
Default Re: External crack

Thats so funny, Jim! Great minds and all that, eh?

About the crack: this subject interests me greatly, as my render will be covered with mosaics which means I probably won't see the cracks if/when they form...

So is a crack in the outside render very serious? If some of you say you left the cracks as is? I thought that even a small crack could wick up enormous amounts of water every time it rains. What about tiling over the top, does that help at all?

Great pizzas btw, talisker!
Reply With Quote
  #7  
Old 03-16-2008, 05:34 AM
Laborer
 
Join Date: Feb 2008
Location: Melbourne, Australia
Posts: 60
Default Re: External crack

Thanks appreciate your support in these difficult times

The insulation material is vermiculite mixed with sand/cement over a blanket.

The top coat is tinted with oxide.

I think the top coat is too thin over the arch, this bit was hard to do and I may have skimped a bit on the thickness

I am having a big pizza party next weekend for Easter. Will report after that.

cheers
Reply With Quote
  #8  
Old 03-16-2008, 05:44 AM
CanuckJim's Avatar
Il Pizzaiolo
 
Join Date: Jan 2006
Location: Prince Albert, Ontario, Canada
Posts: 1,479
Default Re: External crack

All,

I don't think hairline cracks are much of an issue. BUT, exterior cracks on an igloo will allow moisture infiltration, and that is not a good idea. Wet insulators do not insulate. As well, if you've ever seen the face of a house brick that's gotten wet, then frozen, you'll know that the force of the freeze-thaw cycle will kick the front of the brick right off. It's called spalling. Once the cycle begins, in a brick wall or an oven dome, it's virtually impossible to halt. I'd recommend that significant exterior cracks be ground out in a V and filled for just that reason. XJs on the right track with a flexible material of some sort.

Ji
__________________
"Made are tools, and born are hands"--William Blake, 1757-1827
Reply With Quote
  #9  
Old 03-16-2008, 06:09 AM
Dutchoven's Avatar
Master Builder
 
Join Date: Apr 2007
Location: Mississippi
Posts: 931
Default Re: External crack

There is a material used to caulk the joints in log homes...my brother usedit is his...supposed to stretch up to 4 inches I think he said...if it isn't hot it should work because I don't know how it holds up to heat
Dutch
__________________
"Making the simple complicated is commonplace; making the complicated simple, awesomely simple, that's creativity. " Charles Mingus
"Build at least two brick ovens...one to make all the mistakes on and the other to be just like you dreamed of!" Dutch
Reply With Quote
  #10  
Old 03-16-2008, 11:18 PM
carioca's Avatar
Journeyman
 
Join Date: Sep 2006
Location: Charlotte Bay, Australia
Posts: 259
Default Re: External crack

Good to hear others DO have cracks in their render/stucco - I thought I was singularly inept in my cover-up :-)

I've noticed a crack about 5cm (2in) long starting in the two-coat render/stucco at the 'naked' arch near the top of the dome and pointing toward the apex.

I measured the outside temperature at that point when the oven was hot, and it registers 50-odd decrees Celsius (sorry about the missing F, I'm lousy at instant conversions). Perhaps I didn't put down the insulation properly at that point close to the masonry?

Whatever: it hasn't grown in subsequent fires but I agree that it will be best to push some more cement render into that hairline and paint over again.

BTW, the two render coats are covered with two acrylic paint undercoats and two acrylic top coats - I'd have though that stuff is elastic enough to accomodate minuscule movements?!

Cheers,

LMH
__________________
"I started out with nothing, and I've still got most of it"

Last edited by carioca; 03-16-2008 at 11:20 PM. Reason: spelling - why don't I spell check first?!
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Crack in the hearth slab Frances Getting Started 17 01-01-2008 06:51 PM
Crack resistant concrete rlf5 Getting Started 1 07-28-2007 05:09 PM
How much crack is too much crack? aikitarik Pompeii Oven Construction 21 11-21-2005 03:44 PM
Facade Brick Develop a hairline crack tdibratt Pompeii Oven Construction 2 09-07-2005 06:29 AM
? crack resistant, Vemic,& Perlite differences Marcel Getting Started 7 09-07-2005 01:10 AM


All times are GMT -7. The time now is 06:57 PM.

Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
2006/10 Forno Bravo, LLC