How long ?

[Pizza Julian]

So how long should I keep the indispensable tool on each brick before move to the next one?

[joeykramer]

until it sets enough that you dont need the support... as you go higher up, gravity kicks in and you'll need to rely on it more. but for the lower chains, it only needed to be on there 30 secs or so.

[JRPizza]

Joey is right - I found 30-60 seconds to be a sweet spot in timing - if I waited too long to remove the IT I occasionally dislodged the brick. What worked best was to butter up the brick and use the IT to hold it in proper orientation while I pressed down and squeezed out the excess mortar. By the time I scraped off whatever extruded I could work the IT loose and move to the next brick and still maintain a good bond. It might have been a slight problem with my geometry but I had some very slight binding with the IT bracket against the brick for a few courses. By the time I got to the top of the dome I had my mortar consistency and brick moisture figured out pretty well and was able to use the press and hold method without having to clamp the bricks to the IT or use any supplemental holding method.

[Pizza Julian]

Joey, JR Pizza thank you very much for the good tips.