Arch to Dome Transition

[strobes]

This has been asked many times. There is even a thread with the same title started back in 2007. Still what is the Conventional wisdom in 2014 about arch building?
What is best way that yields good result with least labor?

[stonecutter]

Re: Arch to Dome Transition

A rough (voussoirs are not cut to shape) semi circular arch is the easiest to build, and is structurally better than a segmental arch.

[strobes]

Re: Arch to Dome Transition

I'm building 32" oven, 20.5" outside radius. Top of the arch estimated on the fourth layer of bricks, with outer diameter of 16". So looks like arch has to extend in direction of the dome for about 4" to make right connection? Should I use brick full length bricks? Build the arch as dome's layers added or finish it first? With semi circular arch there going to be a straight vertical run between arch and dome prone for cracking?

[wotavidone]

Re: Arch to Dome Transition

This works

http://www.fornobravo.com/forum/8/ne...tml#post167578

[cobblerdave]

Re: Arch to Dome Transition

I'm building 32" oven, 20.5" outside radius. Top of the arch estimated on the fourth layer of bricks, with outer diameter of 16". So looks like arch has to extend in direction of the dome for about 4" to make right connection? Should I use brick full length bricks? Build the arch as dome's layers added or finish it first? With semi circular arch there going to be a straight vertical run between arch and dome prone for cracking?

G'day
Building the arch first of full length brick usually you'll find that you will marry the arch at the top but have a lip protruding into you oven at the bottom. An ash catcher.
Building an arch first of 1/2 bricks usually results in the dome not meeting the arch bricks and you get the "teardrop shape" in you dome. Some slivers of brick can be used to bring it back to round, and no one is the wiser.
I mulled over this when building mine and used a slightly longer brick and ended up with a small lip on the inside but just married my dome at the top with the dome brick just inside of the entrance. Works but...
Seems the better way to go is to build the arch as you build the dome.
In this way you can increase the length of your arch brick as every ring of brick gets smaller . A bit more complex but really it's what you as the builder feel you want.
Having helped someone to do it this way . Don't start every ring of brick at the arch but rather at the back . That the bit you'll see at completion. Solve the angles at the junction as you get to them at each ring of brick.
Hope this helps in some way
Regards dave

[strobes]

Re: Arch to Dome Transition

Dave, Thank you for sharing knowledge. Yes all this make perfect sense.
This is the arch I plan to build. The template for the arch on the right side of the hearth. It's about 6" long in total.

Finally I felt comfortable to start cutting brick today.
And plan to cut 5 degree angle off each solder. Is this correct?
Also all my cutting will be based on this calculator. Are there some details that I need to be aware of?

[cobblerdave]

Re: Arch to Dome Transition

G'day
Yes cutting an angle of the soldier course is a good plan.
Its great you have a calculator for the angles but in the real world they are sometimes not as accurate. Cut one brick for each course and test it first before you commit to cutting more brick for each ring.
Mortar gape will make a big difference. We all build the same oven same brick same size but the keystones are all different sizes.....
Regards Dave

[strobes]

Re: Arch to Dome Transition

As I found 5 degree angle was to small, I bumped to about 12.
this is the link to calculator
https://docs.google.com/spreadsheets...=1#gid=2430978
This tool worked well too
http://www.fornobravo.com/forum/f28/...ble-16780.html