[Gentcpa]

I might not be fully understanding the problem. However I would pull the forms and cut the remaining bricks in thirds. You can clean up what you have so far and work with dome through the top hole that you have now. Use enough mortar so that you squeeze out extra mortar on the next courses so that you don't have to go back and fill in gaps afterwards. I have been using C-Clamps to hold the top bricks in place for a few minutes. Everyone else is correct in that the smaller bricks stay in place better and will hold after a few minutes. Also the smaller brick will reduce the size of open wedge between the bricks.

Also I do not believe mortar is designed to fill such a large area as the top of the dome and could be very susceptible to cracks. If you do go that route you would want to use the castable stuff.

Hope what I said makes sense and try C-clamps it has worked very well for me and I am almost done.

Good luck


Julian