Depth of form used to create opening

[CapePizza]

Is there a standard depth for the form that is used to straddle the bricks that create the opening. I was going to plan on it being 9 inches in depth to accommodate the length of the entire brick.
But wondering if it should be not as deep to work with the bricks that are cut to follow the radius of the oven. Any comments would be welcome. Thanks.

[Chach]

It really shouldn't matter. It does not have to be the full length of the brick. The form's extra length will be sticking out the front anyways since you line up the form with the inside of your radius so nothing with be protruding inside the oven.

Ricky

[JRPizza]

I did mine a different way - I indexed the outside edge of my arch form where I wanted the front face of my arch to be and then set my bricks so they were flush with the outside edge of the form to keep all my arch bricks aligned. The outside face of the arch is what your door will sit against so ideally it will all be in one plane, which placing the form forward facilitates. Ricky is right you don't want your arch bricks protruding into your oven but you cut those as you go and a quarter inch here or there would be much more noticeable on the outside visible face. Depth only has to be sufficient to support a brick so it does not tumble back into the oven while your are building I think mine was about 5". What I think is important is having your form equal height at the front and rear so you don't have tipped bricks - this along with forward placement helps keep the face of the bricks aligned and in plane.

[CapePizza]

Thank you both for the reply. I'm spending a bit of time getting familiar with the arch layout since that, at first, seemed like a bit of a mystery. The more I look at it I have a feeling when I get down to actually building it, hopefully, it will all become apparent. Hopefully :-)

[JRPizza]

As long as you get the arch in the right place fore/aft over half the battle is won. If you build it up as you build the dome all the cuts, although custom, are pretty apparent. Cut to fit and like UtahBeehiver likes to say "mortar is your friend"