Required density of fiberboard insulation

[WJW]

Re: Required density of fiberboard insulation

Actually, I do like the look of a soldier course with a stretcher course running accross the top.

And I just went and looked at your build again and you have four stretcher courses which (if my math is correct) is ten inches as compared to my nine. So it seems it's not a height issue as much as it is an issue of personal preference. Assuming that's the case, I'm good with doing what I think looks best. On the other hand, if there's some structural reason for favoring stretcher courses that I (as a complete rookie) am not aware of, I'd like to know that.

Bill

[brickie in oz]

Re: Required density of fiberboard insulation

And I just went and looked at your build again and you have four stretcher courses which (if my math is correct) is ten inches as compared to my nine.

It was the ruler that gave it away wasnt it?

On the other hand, if there's some structural reason for favoring stretcher courses that I (as a complete rookie) am not aware of, I'd like to know that.

Stretcher bond is stronger in that each course is bonded to the course below.

[david s]

Re: Required density of fiberboard insulation

One of the disadvantages of a dome oven is that anything tall can't be placed near a wall. The soldier course helps that by by making the dome taller. For a barrel oven the end walls and side walls are straight so there is no need for the soldier course. It is also what makes the barrel oven a more suitable form for bread baking, you can fit more in.

[WJW]

Re: Required density of fiberboard insulation

I understand why a soldier course might be needed in a dome and isn't needed in a BVO. I would have assumed that whether you put down three stretcher courses or a single soldier course wouldn't make any real difference ina BVO, but I just happen to like the look of the course running around the oven.

Al says that a stretcher course is stronger because everything is mortared together. I have no experience in these things but that seems counter-intuative to me. Wouldn't the absence of horizontal joints going up the wall make for a greater load bearing ability when it comes to the sheer force pushing outward as a result of the weight of the arch? If the forces are pushing out, isn't the most likely failure point a horizontal joint?

If not, can someone please explain to me why a stretcher course is stronger in this application as compared to a soldier course?

Thanks.

Bill

[brickie in oz]

Re: Required density of fiberboard insulation

If not, can someone please explain to me why a stretcher course is stronger in this application as compared to a soldier course?

Thanks.

Bill

Every 3rd soldier brick will correspond, or very near to, the perpend joint of the stretcher bond going over it, creating a straight joint and weakness.

The ovens are weak enough once heat is applied with out adding to it.

[GianniFocaccia]

Re: Required density of fiberboard insulation

Stretcher bond is stronger in that each course is bonded to the course below

I saw this first-hand when I pulled my soldiers out and replaced them with stretchers. Some of the soldiers were very tightly bonded to each other and some came apart with very little hand-pressure. I believe stretchers provide a superior bond because of the forces of gravity imparted.

One of the disadvantages of a dome oven is that anything tall can't be placed near a wall. The soldier course helps that by by making the dome taller

This is an easy fix. Simply lay the first few courses of stretchers vertically before proceeding inward. The beauty of a dome allows the builder to customize the oven's interior profile in order to address specific needs such as vertical walls, lower ceiling, dome 'shoulder' shape and eliminating uneven heating and cold spots.

[WJW]

Re: Required density of fiberboard insulation

OK... I guess it's unanimous. I like to ask "why", but I'm not dumb enough to refuse to take advice from those who know more than I. Stretcher course it is then.

Thanks guys.

Bill

[david s]

Re: Required density of fiberboard insulation

I understand why a soldier course might be needed in a dome and isn't needed in a BVO. I would have assumed that whether you put down three stretcher courses or a single soldier course wouldn't make any real difference ina BVO, but I just happen to like the look of the course running around the oven.

Al says that a stretcher course is stronger because everything is mortared together. I have no experience in these things but that seems counter-intuative to me. Wouldn't the absence of horizontal joints going up the wall make for a greater load bearing ability when it comes to the sheer force pushing outward as a result of the weight of the arch? If the forces are pushing out, isn't the most likely failure point a horizontal joint?

If not, can someone please explain to me why a stretcher course is stronger in this application as compared to a soldier course?

Thanks.

Bill

Bill,
The reason the stretcher courses are stronger is that with a soldier course and a stretcher course on top of it you will end up with a coinciding vertical join, giving you 12" for a crack to follow vertically. it is the vertical cracking thats more likely and more problematic.That's my understanding anyway.
Dave

[WJW]

Re: Required density of fiberboard insulation

It's funny how you can think you have a good understandoing over crap that you have no idea what you are talking about whatsoever. I'm a relatively competent guy when it comes to certain subjects...so I often think I know more than I do in other subjects. Sort of an occupational hazard of being a self-proclaimed know-it-all.

I was pretty sure that a soldier course would be stronger than a stretcher in this application, but in short order I heard three perfectly good explinations why I was thinking about it ass backwards. It's rather obvious when you think about it...gravity, 12 inch joints, etc...but it just goes to show you there's no substitute for actually knowing what you're talking about.

Bill

[brickie in oz]

Re: Required density of fiberboard insulation

Dont beat yourself up Bill, we are all still learning, its part of getting older.

I had another bricklayer work with me some time ago, he was 20+ years younger than me so was on the mixer making the mud and laying, and doing general labouring as I do.

There was nothing I could teach this guy, he seriously flew off the handle the moment I tried to suggest a new way or technique, he scared me and Im not easily scared.
He would rant about how he has done his time and no one can tell him how its done.
Ive done 40 odd years in the trade and if I can pick up a new way or technique Ill use it no questions asked.
In the end I had to tell him to go away.

[GianniFocaccia]

Re: Required density of fiberboard insulation

It's all good, Bill. Isn't this a cool site, though?

[WJW]

Re: Required density of fiberboard insulation

This is a cool site. People from all over the planet discussing all things pizza ovens.

Bill

[WJW]

Re: Required density of fiberboard insulation

I think I'm going to put a light in the oven. I was reading the thread about what people would do different if they were re-building their oven and noticed the two things that were most commonly mentioned were to add extra insulation and about adding a light.

I think I have the insulation covered...but a light would be very cool. One of the guys (I forget who) posted a link to One Day Glass and they have a product called Neoceram. It's a transparent ceramic designed for use in wood stoves and can take continuous exposure to temps as high as 1470 degrees. I went through their online order program and a custum cut piece 4.5 by 4.5 inches is only twenty-nine dollars.

It seems like it would sure be easy to place a half brick just below the frontmost arch (near the chimmney transition) pointing toward the back of the oven.

What do you guys think and where would you put the glass? What kind of light would you use?

Here's the link
Neoceram?



Bill

[brickie in oz]

Re: Required density of fiberboard insulation

I use old fashioned wood and flame for the light.
The glass being near the front would probably stay black from soot?

[WJW]

Re: Required density of fiberboard insulation

Good point...I guess it needs to be someplace where the carbon will burn clean Is 1470 degrees F a high enough rating??