Second course angle

[stonecutter]

Re: Second course angle

After you finish your dome, you can wrap the dome with the reinforcement, and trowel your cladding mix into it.

I wrap a layer around the soldiers first ( parallel with the slab ) and then lay strips over the dome..cut to a width that prevents bunching. I cut it in a way that leaves strands on the edges, and that allows me to connect them together without any trouble. That doesn't work with smaller size hardware cloth, but usually the rolls are bound with a wire you can use if you cut it into small ties.

The cladding mix should not contain aggregate other than course sand... called concrete or "B" sand depending on where you are located.

[dmyeli]

Re: Second course angle

Thanks for your ideas, StoneCutter!

If I decide to reinforce my soldiers with hardware cloth, do I simply mortar it to the soldiers?

[stonecutter]

Re: Second course angle

How critical is it for me to buttress the soldiers? I have not seen anyone doing this - perhaps because most people are building higher domes.

You can build the entire dome without the buttress, but you should parge the outer surface of the soldiers first, and then the backs of the dome bricks as you lay each course. A parge (no more is needed than 1/2"), is made of the same material as your building mortar.

As Tscar pointed out, you may not have room for buttressing....this is were a reinforced cladding works well, and it will provide all the necessary support for the soldier course.
There are a few options as to what you use for the reinforcement in the cladding ( a layer about 1") like SS needles, chicken wire, hardware cloth etc...its up to you. But it is a must, as cladding without it is not structural.

Finally, my plan is to use sand to shape the dome. Any thoughts on this would be great.

This is the traditional, easiest and most well known centering ( formwork) used in small dome construction....it's been done for centuries and it is very user friendly.

DM

Hope this helps.

[mrchipster]

Re: Second course angle

Brickie in Oz had a good document on one of the posts regarding butress design. Send him a PM aim sure he will respond.

His real name is Al.

[dmyeli]

Re: Second course angle

Wow! Thanks everyone so much for all this input. I truly appreciate your time and ideas - big time!

Chip - thanks for including the idea about wrapping the dome up with cable. This is something that I am going to look in to.

Deejahoh - I understand the radius diagram now. Thanks! Actually, I am using a sand form so I will be able to use the information from your diagram when it comes time. And the cool thing is that I actually understand it!

I would like to consider using firebrick to buttress the dome - I may have room to do this but need to know some things: How high and wide does the buttress need to be?

For example, my soldier is 9 inches high and the next course will add another 2.5 inches. Does the buttress need reach the top of the second course or to the soldier?

Deejayoh - Would I be able to use the concepts in your radius diagram to determine the length of the base of the triangle buttress?

Thanks again, everyone. I am enjoying learning all this new stuff from everyone!

DM.

[mrchipster]

Re: Second course angle

This thread has a good example of a cable providing the extra support for a low dome oven like yours.

http://www.fornobravo.com/forum/f8/l...and-19449.html

Here is a photo from that thread.

[Tscarborough]

Re: Second course angle

If you use the outer surface to buttress you are limited on your insulation value. I have seen it done several ways, but you WILL have to buttress the soldier course in some fashion.

[mrchipster]

Re: Second course angle

My computer with my cad system took a snooze and decided to destroy the hard drive. I am waiting for the replacement to arrive and will rebuild it from my backup, so back to the old fashioned way pad and pen. I hope they are readable.

[UtahBeehiver]

Re: Second course angle

Mr. C.

I am going to buy you a new pad of paper, you have been doing a lot of drawing the past few days. Much appreciated, I'm sure by the posters.

[shuboyje]

Re: Second course angle

Effective radius will be 26.5", because the walls are high and the dome is so flat. He won't be able to use a string unless he can get the center point under the floor

Agree, my typo from my phone probably made it hard to read, what I tried to say was you can do it in CAD or lay it out on the ground. Doing it on the oven proper won't work, darn pesky floor in the way, lol.

[texman]

Re: Second course angle

Buttressing - I have looked this term up and would love clarification on how it relates to building an oven. My assumption is that buttressing in this situation is a process by which an edge is cut into a brick and then the next chain / brick is set partially into this edge to promote some downward force as opposed to complete horizontal forces pushing outwards. I'd love it if anyone out there could clarify this definition for me.

How critical is it for me to buttress the soldiers? I have not seen anyone doing this - perhaps because most people are building higher domes.

Finally, my plan is to use sand to shape the dome. Any thoughts on this would be great.

Again, thanks everyone for taking the time to comment.

DM

I agree with Chip and DJ on the buttress. Those 9' soldiers and a low slope oven change the dynamics and stress of your build. It will work, it just needs some help around that first course to hold the dome as well as your arch. You may me able to incorporate the buttress into your outer wall. I will be honest though- I am not sure that you have much room to buttress that first course looking at the size of you stand. Hopefully someone has some ideas for you.

Texman

[deejayoh]

Re: Second course angle

Chip and Deejayoh - thanks so much for all your ideas - though I really don't understand the way dj boiled "it down to the basics" with the slick little diagram. Any further explanation on the "radius issue" would be wonderful.

Deejayoh - Thanks for putting the work into putting together that wonderful program. It will save me loads of time I'm sure. However, I don't understand some things....

For example, you suggested that I input minus 10.5 inches for the IT height. Can you please explain where you got this number from? My diameter is 36 inches and the distance from the radius to the top, inner edge of the soldier is 20.25 inches.

DM

Hopefully I can break this down - What the graphic I posted showed is the shape of your current build - the diameter of the oven and the height of the walls - as the rectangle in the middle. The circle that goes around them represents the effective radius of the arc (circle section) that you will in order to connect the sides of your dome and still get the correct roof height (assuming I am right that you are targeting 16"). The thing you should take away from the picture is the rectangle + the arc at the top. That's the profile of the inside edge of your finished dome.

The reason that you need to input -10.5 in the spreadsheet is because that's the way the math works out for you to get a dome that is that flat. Don't worry about it, you aren't going to use an IT anyway. But if you decide to use a plywood form, you will want to base it on a 26.5" radius circle.

[mrchipster]

Re: Second course angle

Because your walls (soldiers) are so tall and the forces related to the dome you are building are outward your soldiers will tend to crack apart. Or worse fall over.

Many builders have created cable or chain systems around the soldiers to hold them in. Others have built secondary walls around them.

With a hemispherical dome the force is translated into the floor in your case it is translated into rotational force into space on the tops of the soldiers.

[dmyeli]

Re: Second course angle

Thanks everyone for all the information. I really appreciate it, and appreciate that I am probably well in over my head on this project - but I'll carry on!

Chip and Deejayoh - thanks so much for all your ideas - though I really don't understand the way dj boiled "it down to the basics" with the slick little diagram. Any further explanation on the "radius issue" would be wonderful.

Deejayoh - Thanks for putting the work into putting together that wonderful program. It will save me loads of time I'm sure. However, I don't understand some things....

For example, you suggested that I input minus 10.5 inches for the IT height. Can you please explain where you got this number from? My diameter is 36 inches and the distance from the radius to the top, inner edge of the soldier is 20.25 inches.

Buttressing - I have looked this term up and would love clarification on how it relates to building an oven. My assumption is that buttressing in this situation is a process by which an edge is cut into a brick and then the next chain / brick is set partially into this edge to promote some downward force as opposed to complete horizontal forces pushing outwards. I'd love it if anyone out there could clarify this definition for me.

How critical is it for me to buttress the soldiers? I have not seen anyone doing this - perhaps because most people are building higher domes.

Finally, my plan is to use sand to shape the dome. Any thoughts on this would be great.

Again, thanks everyone for taking the time to comment.

DM

[david s]

Re: Second course angle

You can make some plywood templates for support or fill with sand to required form.