Arch crack

[egalecki]

I have no cracks visible in the oven itself yet- but I have one in my outer arch, to the right of my keystone. If if look upward, I can see daylight all the way through, so it isn't superficial. I guess I'll have to figure out how to buttress the sides, since I'm pretty sure that's the problem. I was hoping to get out of it, since I'm going for an igloo and the buttress will interfere with the shape.

I'm thinking now of getting something decorative which will remain showing on each side. What should it be made of? Where to find it?

Or would it be better just to add another vertical course of brick to each side and have a fatter entry to my igloo?

[christo]

Re: Arch crack

When I had arch problems - I went the low tech approach and mixed up an 80lb bag of concrete (one per side) and made a crude form to butress the side wall of the oven.

I thought it would be a terrible heatsink, but it does not seem to be that bad - one - my side walls were stacked thin side - two the concrete butress did not go all the way to the oven it's self - so conduction has to go through the relatively thin cross section of the brick - or at least that's what I tell myself.

My oven enclosure is a box - so I was able to pour vermiculite over the entire oven and the cement butresses.

Oh yeah, hindsight - after I was done I had some of the ceramic board left and kicked myself for not placing that on the side wall and pouring the butress against that - but I had done the pour before I thought of that.....

BTW I rebuilt the part of the arch after the walls were restabilized with the butresses - I found where the side wall had failed and broke a brick (actually a few came) and put it back together a day or two after the butress had firmed up.

Good luck!!!

Christo

[Les]

Re: Arch crack

Elizabeth,

I plan on using cores on the sides to beef it up. I am going to run rebar throught the cores and into the hearth concrete. I would think that this will suffice. I was also thinking of using the isol board between the two as Christo mentioned, but I think it will make it to "fat"

Les...

[egalecki]

Re: Arch crack

I have a lot of 3 hole bricks from my in-law's recent house build- I could use them on the sides with the rebar. That's a great idea.

I don't know that I need to add blanket or board between- it's the arch and the neck of the igloo, after all. I don't think it matters as much there anyway, heat-wise. I do have extra blanket I could sandwich in, and then it wouldn't be too much extra thickness. Have to think on that one.

[Les]

Re: Arch crack

I don't think it matters as much there anyway, heat-wise.

I concur - it's pretty much up and out at that point.

Les...

[christo]

Re: Arch crack

my butress is right up against the wall and my oven seems to retain heat well.

I put the door in with a few coals in the back and 10 am the next day it is still over 500 degrees.

Christo