Share your crack stories

[brickie in oz]

Re: Share your crack stories

Another crack story.
We went and stayed at my wifes brothers place for a few day for Easter, the ground is so dry after summer, he showed me a fence post that is traveling as the ground dries.
The reference point is a steel post that is concreted in to a corner of a large concrete slab.

The traveling post has moved about 50mm and has stayed perfectly vertical and plumb.

[Tscarborough]

Re: Share your crack stories

Oh yeah, a crack story. When I poured the water table around my oven, I was in a hurry to peel the forms to finish the edge, so about 3 hours after I poured it, I cracked off 4" of one corner. %$@#%&!!!!

[Tscarborough]

Re: Share your crack stories

It is 3/16" HDG ladder wire. The rebar is grouted into the concrete slab through the hearth, and the wire was pre-tensioned with the shims that center it.

To say that sailors/soldiers are inherently weaker is true. That is not an opinion, it is physics. They are, in this instance, also desirable, so the key is to be cognizant of the fact when they are used.

That oven did not crack on it's 200 mile journey, and still hasn't in use.

I hate to see anyone get mad and leave, especially over a discussion in which no one was right or wrong.

[cobblerdave]

Re: Share your crack stories

Shit...........

[stonecutter]

Re: Share your crack stories

David, nothing you said caused that. If we can't discuss and reason (like adults) even if we can't see each others point of view without attacking each others character and getting inflammatory, then that's a personal issue.

To the op, sorry this derailed the thread a bit...hopefully it goes back to crack stories.

[david s]

Re: Share your crack stories

What a pity. Seems Mick has deleted all his posts on this thread and no longer wants to discuss. I enjoyed this discussion and his contributions. I now feel bad that I raised the initial doubt about the inherent weakness of using soldiers if it has produced a casualty.

[brickie in oz]

Re: Share your crack stories

Originally Posted by wotavidone
Can you assist? How does one de-register

Just unregister from subscriptions, or, ask admin to unregister you.

[stonecutter]

Re: Share your crack stories

That's one way to put it.

Tscar, is that ladder wire you are using?

I am considering the use of banding on my current build. I have never used it before, even on the Neo domes with soldier courses, but I have some SS termination bar and SS Seismic wire that would work perfect....just for some extra reinforcement and because I have it. How did that Neo travel on your friends trailer? Any cracks?

[deejayoh]

Re: Share your crack stories

Well.... that was interesting.

[stonecutter]

Re: Share your crack stories

Also, and I have said this before on this board. I am a professional in the industry, so I am limited to best practices on any advice I give. Crazy ideas might work, but unless I personally have done it, or it is considered an industry best practice, I will not recommend it. Obviously you (royal you) can do what you want, but you will not get anything else from me than best practices or personal experience.

X2..'nuff said.

[Tscarborough]

Re: Share your crack stories

Also, and I have said this before on this board. I am a professional in the industry, so I am limited to best practices on any advice I give. Crazy ideas might work, but unless I personally have done it, or it is considered an industry best practice, I will not recommend it. Obviously you (royal you) can do what you want, but you will not get anything else from me than best practices or personal experience.

[Tscarborough]

Re: Share your crack stories

The problem with using un-reinforced cladding is that when it cracks (because it WILL crack), then the cladding is no longer working as a tension ring, and is thus no longer supporting the dome. That is why the Italians use the reinforced shell to buttress the non-reinforced cladding of tufa.

Edit-Also note that with a sailor course, you only have 2.5" of refractory mass, so the cladding is refractory concrete to build the mass up to a total of 5".

[stonecutter]

Re: Share your crack stories

I am not looking for validation of my construction method. The validation of my method is that it is staying up and not cracking. I'm not even advocating the use of my method to anyone else.

I was just offering the point that every little bit helps, and I do know how an arch works without your endless repetition of something every half decent school kid knows.

You guys seem so rigid. Not at all open to ideas.
For example, with regard to Tscars pictures below, might it not have been just as simple to clad that ring of bricks with some scoriacrete which has insulating properties and is as strong as the proverbial brick outhouse? Probably wouldn't need to drill re-bar in. and the bottom section of that dome wouldn't have layer of extra thermal mass that Tscar's method undoubtedly added.

You can help me with something though. I've seen so many poor newbies discouraged and confused by all the so-called experts, that I've decided that people like you make this forum too irritating, but I can't seem to find out how to remove myself from it.
Can you assist? How does one de-register?

Sorry you interpret it that way. The repetition was there because it doesn't appear that you do how forces in an arch work. I never got inflammatory, never said I wasn't open to new ideas..but apparently feelings are hurt when reasoning was used to show how something won't work to prevent cracking.
BTW, sarcasm doesn't really encourage new builders to ask questions either.

[Tscarborough]

Re: Share your crack stories

Plus a tension member is used at the spring line. The vertical brick (sailor/soldier) has the line of force through the top of the brick, not the base. A sailor/soldier with cladding works just fine, but is only as strong as the cladding.

The classic Neapolitan design uses the insulation to buttress the sailor course against the reinforced stucco shell and no cladding. The downside to this is that the insulation used (tufa) is not that good of an insulator. A better method is a cladding that is reinforced by some method to allow it to act as a tension ring. The difficulty here is that it is not a closed ring because of the entry. Here is how I solved it:

[stonecutter]

Re: Share your crack stories

No, your replies relate to not understanding the point I was trying to make.
I'm trying to make the point that, given I have apparently used a brick layout that is unstable, the fact that I have mortared it to a substrate that isn't friable, may be helping to hold it in place, by helping to counter the outward forces you speak of.. If the same course of bricks was mortared to a layer of vermicrete, and these outward forces were applied, I reckon the vermicrete would fail where the mortar joins it, since it is brittle and friable and has little flexural strength, according to Tscar.
Perhaps the high strength of the substrate consititutes the "tension member tying the bottom of the arches together" that Tscar also mentions.
Anyway, I was merely offering an alternative, and I am beginning to suspect you blokes are being deliberately obtuse, so I'll say no more on the subject.

Obtuse, not at all....practicing the art of futility more like. The explanations are trying to make you understand that.....


1) Mortaring the base coarse to substrate wont stop cracking no matter what it is made of...mentioned before, and explaining the way forces work in an arch should have cleared that up.

2) A slab is not a tension member. Banding(with straps), buttressing, and Cladding(what you said you have done) IS. Mentioned before, several times.

It seems you never got what you are looking for, which is validation of the method you constructed your oven.